Post on 31-Aug-2019
Hindawi Publishing CorporationApplied and Environmental Soil ScienceVolume 2013 Article ID 252861 11 pageshttpdxdoiorg1011552013252861
Research ArticlePhysicochemical Properties and Surface Charge Characteristicsof Arid Soils in Southeastern Iran
A H Moghimi1 J Hamdan1 J Shamshuddin1 A W Samsuri1 and A Abtahi2
1 Department of Land Management Faculty of Agriculture Universiti Putra Malaysia 43400 Serdang Selangor Malaysia2 Department of Soil Science Faculty of Agriculture Shiraz University Shiraz 7915847669 Iran
Correspondence should be addressed to A H Moghimi moghimiabolhasangmailcom
Received 2 March 2013 Revised 15 May 2013 Accepted 20 May 2013
Academic Editor Davey Jones
Copyright copy 2013 A H Moghimi et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
The majority of previous studies on surface charge characteristics were done on tropical and subtropical soils Information of suchstudies in the arid regions is limited A study was conducted to investigate the relation between soil chemical and mineralogicalproperties and surface charge characteristics of an arid region in Southeastern Iran Eight soil pedons representing the alluvialand the colluvial deposits were described and their mineralogical and physicochemical properties were examined The commonclay minerals in the studied area are smectite palygorskite kaolinite chlorite and illite The point of zero charge (pH
0) values
are low (285ndash335) in all soils mostly affected by organic carbon (OC) and free iron oxide (Fed) pH0 has a significant negativecorrelation with pH under field conditions (119903 = minus045lowast 119875 lt 005) The point of zero net charge (PZNC) levels for all the soils werelt2 due to the excess negative charge in these soils The estimated PZNC values were less than pH
0in all soils because of the high
permanent negative charge in these soils The permanent negative charge (120590119901) of the soils studied is high and it has a significant
positive correlation with pH CEC Na Mg SAR clay content palygorskite OC and Fed
1 Introduction
Soil surface charges affect the chemical properties of soil byvarying the quantity of electric and surface charge densitySurface charge properties have an important bearing on themigration of ions in soil the formation of organomineralcomplexes soil structure plant nutrition and the dispersionflocculation swelling and shrinkage of the soil fractions [1]Based on differences in the surface properties soils can beclassified into two basic categories permanent-charge soilsand variable-charge soils [2 3]
Point of zero charge (PZC) often denoted as pH0is one
of the most important parameters used to describe variable-charge surfaces [4] Uehara and Gillman [5] indicated thatpH0is the pH where the amounts of negative and positive
charge of variable charge components where these are equalThe pH
0value for the temperate region of Iran was reported
in the range of about 26 to 375 [6] Anda et al [7] reportedthat the pH
0of three Oxisols in Malaysia was about 39 to
57The previous studies showed that the pH0values decrease
with increasing organic matter content and increase with
increase in sesquioxides [6ndash8] Taubaso et al [9] reported thatthe pH
0values of Argentinean provinces soils were smaller
than the pH in water indicating that these soils had negativecharge under natural conditions
Gonzales-Batista et al [10] reported that for systems freeof permanent charge the point of zero net charge (PZNC)should coincide with pH
0 but for systems where permanent
and variable charges coexist PZNC may differ from pH0
Usually in the young soils (Entisols or Inceptisols) PZNCis lower than its pH
0and higher than pH
0if the soils are
highly weathered such as Oxisols [9] In addition the modelof Uehara and Gillman [11] and Yu [2] predicts that in soilshaving permanent negative charge the PZNC value is lowerthan the pH
0and vice versa
Most studies on soil surface charge properties wereconducted in tropical and subtropical regions where the soilsare poor and low in negative charge In Iran Sharami et al [6]conducted similar study for temperate soils of the Northernregion but no studywas done on arid regions of Southern Iranor elsewhere in the world The electrochemical properties ofsoils are useful fundamental knowledge in solving the fertility
2 Applied and Environmental Soil Science
problems of soils of the arid regions For example in thearid regions the NH
4
+ fixed by soil particles and leachedout as NO
3
minus form due to high permanent negative charge inthe surface of soil particles [12] in comparison with highlyweathered soils whereNO
3
minus leaching because of high positivecharge present in the soils [13] The objectives of this studywere to determine the physicochemical and mineralogicalproperties the pH
0 PZNC and permanent negative charge
(120590119901) and to determine the relation between pH
0and 120590
119901with
characteristics of arid soils in Southeastern Iran
2 Materials and Methods
21 Description of the Study Area The studied area is locatedin the province of Hormozgan Southeastern Iran betweenlatitude 28∘81015840 and 28∘151015840 North and longitudes 56∘51015840 and 56∘151015840 East (Figure 1) The climate is arid with an average annualprecipitation of about 162mm and evaporation of 4243mmBurdon [14] reported that the estimated potential evapotran-spiration could be in excess of 50 times the mean annual pre-cipitation The temperature regime is hyperthermic with anaridic and usticmoisture regimes [15]The sedimentary rocksaccompanyingmarine deposits of the Tertiary age formed thecatchment area which is predominantly composed of thickalluvial and colluvial materials occasionally deposited by theDehshaykh River for the past thousands of years The riveris dry most of the time except during heavy downfall Thecatchment is currently cultivated with wheat maize potatoand watermelon as important agricultural crops [16]
Eight pedons were selected among the dug profilesrepresenting alluvial fan and colluvial deposits along theslope area of the catchment by geopedology approach anddifferent soil horizons were sampled for laboratory analysisThe morphological properties of the soils were described inthe field [17] and were classified according to the USDA SoilTaxonomy [18]
22 Methods
221 Physical and Chemical Analyses Field study and sam-ples collectionwere carried out in the summer season of 2009(August to September) The soil samples were air-dried andsieved with a 2mm sieve and kept in plastic bags prior toanalysis
The particle size analysis was carried out by the pipettemethod [19] Organic matter content of the soil was deter-mined by the wet combustion procedure of Walkley andBlack [20] and Fe
2O3was estimated by the dithionite-citrate-
bicarbonate method [21] The pH was measured in thesupernatant suspension of 1 1 soil water suspension pH [17]1 25 liquid 001M CaCl
2solution (pHCaCl
2
) [22] and 1 25soil H
2O (pHH
2O) and 1 25 soil 1MKCl solution (pHKCl)
[23]Thebulk density (120588119887) was estimated by coremethod [24]
and the electrical conductivity (EC) analysis wasmeasured inthe saturated extract [25] The calcium carbonate equivalent(lime) was measured by acid neutralization [26] exchange-able cations content and the cation exchange capacity (CEC)of the soils were determined by the 1M ammonium acetate
40∘
35∘
30∘
25∘
45∘
50∘
55∘
60∘
65∘
N
Paki
stan
Afg
hani
stan
Turkmenistan
Study area
Bandarabbas
Caspian Sea
Tehran
Iran
Shiraz
Persian
Turk
ey
Iraq
Kuwait
Saudi ArabiaGulf
Figure 1 Location of the study area
(pH 7) method The exchangeable cations (Ca2+ and Mg2+)in the leachate were determined by atomic absorption spec-trophotometer (AAS Perkin-Elmer 047-1705) whereas K+andNa+ weremeasured by flame spectrophotometerThe soilsolution data (Na+ Ca2+ Mg2+ given in cmolckg
minus1) was usedto calculate the sodium adsorption ratio (SAR) where SAR =Na+[(Ca2+ + Mg2+)2]minus05
222 Determination of Point of Zero Charge Point of zerocharge (PZC) denoted as pH
0 is defined as the pH at which
the net charge on the variable charge components is zeroand was determined according to the method of Gillman andSumner [27] Six portions of 2 g of 2mm air-dried sampleswere weighed into 50mL plastic centrifuge tubes and shakenwith 20mL of 01M CaCl
2for 2 h to saturate the soil with
Ca The suspension was centrifuged (3000 rpm 10min) andthe supernatant was discarded The Ca saturated soil waswashed twice with 20mL of 0002MCaCl
2and after the
third addition of 20mL of 0002CaCl2 the pH was adjusted
to six values of 01MHCl in the range of 35 to 6mL bydropwise addition Equilibration of the pH took several daysWhen equilibrium occurred for 0002MCaCl
2 the pH was
recorded as pH0002
then 05mL of 2MCaCl2was added
to each sample and shaken for 3 h and pH was recordedthereafter and designated as pH
005 For each tube 120575pH was
calculated as (pH005minus pH0002
) The pH0was obtained from
the plot of 120575pH against pH0002
The pH0was identified as the
point where 120575pH was zero
223 Determination of Point of Zero Net Charge The pointof zero net charge (PZNC) the pH at which net surfacecharge of the whole system (taking into account both per-manent and variable charge colloids) is zero was obtainedby interpolation of the data from the measurement of chargevariation with pH Charge variation with pHwas determinedby the fingerprint method of Gillman and Sumner [27]Two-gram air-dried soil samples in 50mL preweighed plasticcentrifuge tubes were shaken with 20mL of 01MCaCl
2
for 2 h to saturate the soil with Ca The suspension was
Applied and Environmental Soil Science 3
Table 1 General information on the studied pedons
Pedon Soil classification Relief Physiography Land use Parent material Drainage
1Fine loamy mixed(calcareous) hyperthermicCalcic Haplosalids
Flat Piedmont alluvialplain Saline pasture Calcareous alluvium Imperfectly drained
2Coarse loamy mixed(calcareous) hyperthermicAridic Ustorthents
Almost flat River alluvial plain Bare Calcareous alluvium Well drained
3Fine loamy mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Plowed Calcareous alluvium Moderately well
drained
4Loamy skeletal mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Harvested wheat Calcareous alluvium Well drained
5Sandy skeletal mixed(calcareous) hyperthermicAridic Ustifluvents
Almost steep Alluvial-colluvialfan pasture Calcareous alluvium Well drained
6Coarse loamy mixed(calcareous) hyperthermicAridic Ustorthents
Flat River alluvial plain Plowed Calcareous alluvium Moderately welldrained
7Fine loamy mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Plowed Calcareous alluvium Well drained
8Sandy skeletal mixed(calcareous) hyperthermicAridic Ustorthents
Almost steep Alluvial-colluvialfan Pasture Calcareous alluvium Well drained
centrifuged (3000 rpm 10min) and the supernatant wasdiscardedTheCa saturated soil waswashed twicewith 20mLof 0002MCaCl
2and after the third addition of 20mL of
0002MCaCl2soil suspension was recorded and thereafter
the pH was adjusted to different values by dropwise additionof 01MHCl or saturated Ca(OH)
2 The equilibration of the
pH took several days After the pH was stable the suspen-sion was centrifuged and the supernatant was collected todetermine Ca Al and Cl in the entrained solution Thetubes were then weighed to estimate the volume of entrained0002MCaCl
2
The soil was then extracted with 20mL of 1m NH4NO3
and Ca Al and Cl were determined in the extract Allowingfor entrained Ca Al and Cl the amounts of cation (Ca2+ +Al3+) and anion (Clminus) adsorbed were calculated and equatedwith total negative (CECT) and positive (AEC) chargerespectively The amount of Ca adsorbed was equated withbasic cation exchange capacity (CECB) Aluminum and Cawere determined by AAS and Cl measured by silver nitratetitration method [28] The PZNC was identified as the pHvalue where total negative and positive charges are equalThepermanent charge was estimated as the difference betweenAEC and CECT values at pH
0[29]
224 Mineralogical Analyses Removal of chemical cement-ing agents and separation of the different size fractions ofsoils were carried out according to Mehra and Jackson [21]Kittrick and Hope [30] and Jackson [31] Organic matterand carbonate were removed with 30 H
2O2and 1NHCl
respectively X-ray diffraction (XRD) studies were carriedout on both fine and coarse clay fractions while equalconcentrations of clay suspensions were used for all samplesin order to allow for a more reliable comparison betweenrelative peak intensities for different samples Two drops ofthe prepared suspension were used on each glass slide Theclay samples were finally examined by XRD analysis usinga Philips diffractometer with Co K120572 radiation in order toallow for a more reliable comparison between the relativeheights of peaks in the XRD data The K-saturated sampleswere studied both after drying and heating at 500∘C for4 h to identify kaolinite in the presence of trioctahedralchlorite and samples were also treated with 1NHCl at 80∘Covernight Semiquantitative estimation of clay minerals wasmade by directly converting the diffraction peak areas usingthe method of Karanthanasis and Hajek [32] Selected driedclay particles of the soils were studied under a transmissionelectron microscope (TEM LEO 912 AB) The samplesdispersed in 100 alcohol and 100 120583L of the suspension wasdropped on formvar-coated Cu grids
The soil chemical and mineralogical properties and theirrelationship with the surface charge characteristics wereanalyzed by multiple and simple linear regression using SASand Excel softwares
3 Results and Discussion
31 Field Observation and Soil Classification The soil chem-ical data are shown in Table 1 Pedons 1 3 7 and 4 are soilsdeveloped on the piedmont alluvial plains while pedon 2
4 Applied and Environmental Soil Science
Table 2 Some physical properties of the representative profiles
Soil number Depth (cm) Clay Silt Sand Texture+ Structurelowast 120588119887(g cmminus3) Gravel ()
()
1
0ndash25 34 56 10 SiCL WP 154 mdash25ndash78 14 36 50 L Ma 150 mdash78ndash110 32 48 20 CL WG 153 mdash100ndash150 12 22 66 SL Ma 151 mdash
2
0ndash20 10 40 50 L WP 152 mdash20ndash50 10 8 82 LS Sg 153 mdash50ndash100 12 16 72 SL Sg nd 35100ndash150 8 2 90 S Sg 136 mdash
30ndash30 18 38 44 L WG 144 mdash30ndash80 16 37 47 L WG 140 mdash80ndash150 16 12 72 SL Sg 149 mdash
4
0ndash20 10 16 74 SL Sg nd 3020ndash70 8 16 76 SL Sg nd 5070ndash95 14 12 74 SL Sg nd 1095ndash150 12 4 84 LS Sg nd 50
5 0ndash45 18 20 62 SL Sg nd 8545ndash150 24 20 56 SiL Sg nd 65
60ndash42 16 34 50 L WG 141 mdash42ndash88 10 12 78 SL Ma 137 mdash88ndash150 12 26 62 SL Ma 141 mdash
70ndash36 24 42 34 L WG 135 mdash36ndash86 30 50 20 CL WG 139 mdash86ndash150 26 38 36 L WG 141 mdash
80ndash30 12 14 74 SL Sg nd 7030ndash70 10 8 82 LS Sg nd 7570ndash150 14 14 72 SL Sg nd 80
Texture+ SL sandy loam LS loamy sand L loam S sand SiL silty loam SiCL silty clay loam Structurelowast Ma massive Sg single grain WP weak platy WGweak granular nd no determine
and 6 are formed on river alluvial plains Pedons 5 and 8are formed on alluvial colluvial fans and sited on a higherslope area All pedons were dug with a maximum depth of150 cm and obvious textural changes throughout the profilewere observed Since the plain is part of an alluvial andcolluvial fan the deposition of materials from the alluvialand colluvial wash varies from time to time creating differenttextural layers This was observed in all the soils studiedwhere the soils textural changes were extreme particularlyfor the silt and sand content There were also variations intheir structures which is also associated with the amountof sand and silt in the soils The soils tend to be massivewhen the silt content is high otherwise the structures wouldbe single grain when the sand content is high The roundednature of these gravels suggests that they were washed anddeposited along part of the plain All soils were weaklydeveloped and evidenced by weak horizon formation in theprofiles Under the arid environment with annual precipita-tion value of less than 200mm and evaporation of more than4000mm one would surely expect to see slow rate of soilpedological development because of very low rate of PET0[33]
The eight representative profiles were classified usingthe USDA Soil Taxonomy [18] All soils are young anddifferentiated by their moisture regime They were identifiedas Calcic Haplosalids Aridic Ustorthents and Aridic Ustiflu-vents (Table 1)
32 Physical Properties The soil physical data are presentedin Table 2 None of the soil physical characteristics showany clear trend with depth In pedon 1 the clay contentdistribution was irregular In pedons 4 5 7 and 8 clayincreases with depths while in pedon 2 it increased onlyuntil the top 100 cm In contrast to the above observationspedon 6 exhibits a remarkable decrease in clay content withsoil depth In pedons 3 and 4 the silt content decreases withdepth The sand size particles are dominant in all pedonsexcept for pedons 1 and 7 but their distribution throughoutthe profile was very irregular The results are consistent withthe nature of alluvial and colluvial deposition that variesfrom time to time Khresat and Qudah [34] also observeda similar deposition trend on studying the Azraq Basin inNortheastern Jordan which is also formed from alluvial andcolluvial deposition
Applied and Environmental Soil Science 5
33 Chemical Properties The soil chemical data of the repre-sentative profiles are presented in Table 3 The soils are alka-line and calcareous in nature containing 1983 to 6145CaCO
3throughout the profiles All soils have pH values
above 70 showing that they are alkalineThe average electricalconductivity values exhibited some variations among the soilsstudied placing these soils from slightly saline to saline levelIn pedons 2 4 5 and 8 the soils were noted to be nonsalinewith EC values ranging from 04 to 264 dSmminus1 while soils inpedons 3 6 and 7 were slightly saline with EC values rangingfrom 21 to 7 dSmminus1 Pedon 1 soil was observed to be salinewith EC values ranging from 1811 to 305 dSmminus1 The Nacontent showed slight variability among the soils studied Inpedons 2 5 and 8 the amount of Na was between 04 and68 cmolckg
minus1 as compared to pedons 1 3 4 6 and 7 whichNa ranges between 184 in 20 cmolckg
minus1 The soils howeverare nonsodic with SAR values ranging from 03 to 77 Thecation exchange capacity ranges from 17 to 414 cmolckg
minus1In pedons 1 3 6 and 7 the CEC was between 195 and411 cmolckg
minus1 as compared to pedons 2 4 5 and 8 withvalues of 117 to 215 The organic carbon content was low inall soils which is common for soils of these regions where thevegetation is scarce
The variability of the soil chemical properties againreflects the alluvial and colluvial nature of soil deposition andtheir rocks origin According to Navai [35] the predominantrocks surrounding the study area are limestone dolomite(Jahrom Formation) limestone marl (Aghajari Formation)limestone green marl (Mishan Formation) salt domes (Hor-moze Formation) and conglomerate (Bakhtiari Formation)The weathered rock materials from these formations werewashed to the catchment areas and these contributed to thevariability in the soil physicochemical properties
34 Clay Mineralogy The clay minerals of the examinedsoils are presented in Table 4 Based on 119889-spacing theminerals identified through XRD diffractograms are as fol-lows smectite (1402ndash15 318ndash320 A) palygorskite (104ndash106 634ndash64 323 and 425ndash447 A) chlorite (701ndash711353 A) illite (997ndash1009 498ndash502 A) kaolinite (72ndash73228 A) and sepiolite (1210ndash1211) The presence of smectitewas proven by Mg-saturated clay samples solvated by ethy-lene glycole which expanded due to treatment with Mg-saturated
The common minerals in all samples of the studied areaare smectite palygorskite illite chlorite and kaolinite Kaoli-nite is found in all soils with the exception of pedon 8 Sepi-olite exists in pedons 3 4 6 and 7 The dominance of theseminerals in the arid regions agrees with the results obtainedby Owliaie et al [36] and Emadi et al [37] Palygorskiteand sepiolite are fibrous clays and are considered to be ofauthigenic origin inherited from weathered parent materialsof the surrounding hills and plateaus [33] The presence ofkaolinite inmost soils is probably due to inheritance from theweathering of coarse and fine materials transported from thesurrounding upland zones Itmay also suggest the occurrenceof palygorskite and sepiolite kaolinization that apparentlymay be due to the effect of organic matter decomposition and
fibrous clay destabilization caused by Mg uptake by plants[38]
35 Soil Electrochemical Properties
351 Point of Zero Charge Characteristics The pH0values
varied from 28 in subsurface horizon of pedon 2 to 335 inthe topsoil horizon of pedon 1 (Table 4) and were positivelycorrelated with the Fed content (119903 = 087
lowastlowast 119875 lt 001) whichwas far more than its correlation with the OC percentage (119903 =minus083
lowastlowast 119875 lt 001) The pH0also has a negative significant
correlation with pHH2O (119903 = minus045lowast 119875 lt 005) Hence the
Fed content had more effect on pH0values compared with
theOC content in the soils studiedThe respective pH0values
of organic matter and sesquioxides have been reported todecrease and increase respectively [8 39]
Li and Xu [40] reported that the layer silicate clays (2 1clays) decreased the pH
0values while the 1 1 clay minerals
as kaolinite increased the pH0 Besides Uehara and Gillman
[5] reported that the oxides of Fe andAl have high pH0values
(pH 7ndash9) while silica (SiO2) and organicmatter have low pH
0
values Therefore the low levels of pH0in the present study
were probably related to layer silicate clays (2 1 clays) andhigh pH in all the pedons
The values of 120575pH (pH0minus pHCaCl
2
) indicate the evolutionof positive and negative charges on the variable chargecomponents [11] The greatest values of 120575pH (pH
0minus pHCaCl
2
)were related to subsurface horizon of profile 2 (minus510 units)which agreed with its strongly negative net charge in the fieldconditions (Table 4) The mineralogical data also confirmedthe occurrence of significant amounts of layer silicate min-erals (smectitic type) in this profile (Table 4) Generally thevariations of 120575pH (pH
0minuspHCaCl
2
) for all the studied horizonsshowed a rather high level (between minus425 and minus510 units)(Table 4) which was in accordance with their CEC levels(Table 3) However because of a large quantity of layer silicateminerals (2 1 clays) and a scarcity of 1 1 clays and Fed thisrising trend from surface to subsurface horizons was not sonoticeable
352 Point of Zero Net Charge (PZNC) For all the studiedsoils the PZNC levels were lt2 which was probably due tothe excess negative charge in these soils Gonzales-Batista etal [10] reported that for systems free of permanent chargePZNC should coincide with pH
0 but for systems where
permanent and variable charges coexist PZNC may differfrom pH
0 Usually in the young soils (Entisols or Inceptisols)
PZNC is lower than its pH0and higher than pH
0if the soils
are highly weathered such as Oxisols [41] In addition themodel of Uehara and Gillman [11] and Yu [2] predict thatin soils having constant negative charge the PZNC value islower than pH
0and vice versa None of the charge variation
curves of the samples indicated the PZNC in pH betweenranges of 26 and 6 which was due to the excessive amountof negative charge compared with the positive charge inthese ranges of pH Besides the amount of estimated ZPNCin all the samples was lower than the pH
0 confirming the
presence of the permanent negative charge in these soils
6 Applied and Environmental Soil Science
Table3Ch
emicalprop
ertie
softhe
representativ
eprofiles
Soilnu
mber
Depth
(cm)
pHCa
Cl2
pHH2O
pHKC
lΔpH
(KClminusH
2O)
OC
SAR
CCE
EC dSmminus1
CEC
K+Na+
Mg2
+Ca2
+
Fed(
)(125)
cmol
ckgminus
1
1
0ndash25
765
779
760
minus019
034
742137
2985
414
067
2085
65
016
25ndash78
760
776
755
minus021
020
702498
275
263
022
1445
35
015
78ndash110
755
768
750
minus018
023
66
1983
325
334
036
1672
43
014
100ndash
150
770
787
762
minus025
012
772370
1811
313
017
154
52
33
015
2
0ndash20
785
797
780
minus017
018
36
2704
096
215
023
68
48
25
009
20ndash50
790
803
786
minus017
014
37
2755
040
182
022
57
46
22
010
50ndash100
780
795
773
minus022
013
182832
120
154
020
34
43
24
009
100ndash
150
790
794
774
minus020
016
07
2446
093
117
017
1417
23
010
30ndash
3077
579
077
0minus020
037
35
515
428
233
040
7767
28
011
30ndash80
779
793
774
minus019
020
46
5716
700
347
025
121
1032
013
80ndash150
783
797
778
minus021
017
45
5897
548
295
022
108
837
009
4
0ndash20
785
794
780
minus014
033
24
2884
264
176
051
52
47
53
010
20ndash70
793
802
792
minus010
035
30
2885
145
161
018
52
1346
012
70ndash9
578
079
277
5minus017
030
102729
103
144
018
184
1548
011
95ndash150
794
801
790
minus011
043
162798
121
117
015
26
08
43
015
50ndash
4577
578
8772
minus016
035
155820
154
151
021
28
06
65
012
45ndash150
790
804
785
minus019
038
03
5645
037
132
020
04
05
64
013
60ndash
4277
879
771
minus019
029
39
2824
516
275
039
9766
65
009
42ndash88
790
808
786
minus022
033
26
2353
210
195
017
57
48
50
011
88ndash150
789
806
787
minus019
016
48
2536
492
258
023
108
58
45
012
70ndash
3676
878
175
7minus024
037
29
6145
455
243
022
69
51
67
010
36ndash86
780
795
772
minus023
039
21
6041
525
267
024
54
61
64
009
86ndash150
784
798
780
minus018
029
29
6067
496
258
026
7589
45
010
80ndash
3078
079
1776
minus015
024
22
3112
057
168
036
426
43
009
30ndash70
785
789
783
minus006
025
21
3190
080
184
024
38
22
48
006
70ndash150
781
785
778
minus007
026
33
285
066
175
018
627
43
007
OC
organicc
arbo
nSA
Rsodium
adsorptio
nratio
CEC
cationexchange
capacityFe ddith
ionitecitrateb
icarbo
nateC
CEcalcium
carbon
atee
quivalentEC
electric
alcond
uctiv
ity
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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EcologyInternational Journal of
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Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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EarthquakesJournal of
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BiodiversityInternational Journal of
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ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
2 Applied and Environmental Soil Science
problems of soils of the arid regions For example in thearid regions the NH
4
+ fixed by soil particles and leachedout as NO
3
minus form due to high permanent negative charge inthe surface of soil particles [12] in comparison with highlyweathered soils whereNO
3
minus leaching because of high positivecharge present in the soils [13] The objectives of this studywere to determine the physicochemical and mineralogicalproperties the pH
0 PZNC and permanent negative charge
(120590119901) and to determine the relation between pH
0and 120590
119901with
characteristics of arid soils in Southeastern Iran
2 Materials and Methods
21 Description of the Study Area The studied area is locatedin the province of Hormozgan Southeastern Iran betweenlatitude 28∘81015840 and 28∘151015840 North and longitudes 56∘51015840 and 56∘151015840 East (Figure 1) The climate is arid with an average annualprecipitation of about 162mm and evaporation of 4243mmBurdon [14] reported that the estimated potential evapotran-spiration could be in excess of 50 times the mean annual pre-cipitation The temperature regime is hyperthermic with anaridic and usticmoisture regimes [15]The sedimentary rocksaccompanyingmarine deposits of the Tertiary age formed thecatchment area which is predominantly composed of thickalluvial and colluvial materials occasionally deposited by theDehshaykh River for the past thousands of years The riveris dry most of the time except during heavy downfall Thecatchment is currently cultivated with wheat maize potatoand watermelon as important agricultural crops [16]
Eight pedons were selected among the dug profilesrepresenting alluvial fan and colluvial deposits along theslope area of the catchment by geopedology approach anddifferent soil horizons were sampled for laboratory analysisThe morphological properties of the soils were described inthe field [17] and were classified according to the USDA SoilTaxonomy [18]
22 Methods
221 Physical and Chemical Analyses Field study and sam-ples collectionwere carried out in the summer season of 2009(August to September) The soil samples were air-dried andsieved with a 2mm sieve and kept in plastic bags prior toanalysis
The particle size analysis was carried out by the pipettemethod [19] Organic matter content of the soil was deter-mined by the wet combustion procedure of Walkley andBlack [20] and Fe
2O3was estimated by the dithionite-citrate-
bicarbonate method [21] The pH was measured in thesupernatant suspension of 1 1 soil water suspension pH [17]1 25 liquid 001M CaCl
2solution (pHCaCl
2
) [22] and 1 25soil H
2O (pHH
2O) and 1 25 soil 1MKCl solution (pHKCl)
[23]Thebulk density (120588119887) was estimated by coremethod [24]
and the electrical conductivity (EC) analysis wasmeasured inthe saturated extract [25] The calcium carbonate equivalent(lime) was measured by acid neutralization [26] exchange-able cations content and the cation exchange capacity (CEC)of the soils were determined by the 1M ammonium acetate
40∘
35∘
30∘
25∘
45∘
50∘
55∘
60∘
65∘
N
Paki
stan
Afg
hani
stan
Turkmenistan
Study area
Bandarabbas
Caspian Sea
Tehran
Iran
Shiraz
Persian
Turk
ey
Iraq
Kuwait
Saudi ArabiaGulf
Figure 1 Location of the study area
(pH 7) method The exchangeable cations (Ca2+ and Mg2+)in the leachate were determined by atomic absorption spec-trophotometer (AAS Perkin-Elmer 047-1705) whereas K+andNa+ weremeasured by flame spectrophotometerThe soilsolution data (Na+ Ca2+ Mg2+ given in cmolckg
minus1) was usedto calculate the sodium adsorption ratio (SAR) where SAR =Na+[(Ca2+ + Mg2+)2]minus05
222 Determination of Point of Zero Charge Point of zerocharge (PZC) denoted as pH
0 is defined as the pH at which
the net charge on the variable charge components is zeroand was determined according to the method of Gillman andSumner [27] Six portions of 2 g of 2mm air-dried sampleswere weighed into 50mL plastic centrifuge tubes and shakenwith 20mL of 01M CaCl
2for 2 h to saturate the soil with
Ca The suspension was centrifuged (3000 rpm 10min) andthe supernatant was discarded The Ca saturated soil waswashed twice with 20mL of 0002MCaCl
2and after the
third addition of 20mL of 0002CaCl2 the pH was adjusted
to six values of 01MHCl in the range of 35 to 6mL bydropwise addition Equilibration of the pH took several daysWhen equilibrium occurred for 0002MCaCl
2 the pH was
recorded as pH0002
then 05mL of 2MCaCl2was added
to each sample and shaken for 3 h and pH was recordedthereafter and designated as pH
005 For each tube 120575pH was
calculated as (pH005minus pH0002
) The pH0was obtained from
the plot of 120575pH against pH0002
The pH0was identified as the
point where 120575pH was zero
223 Determination of Point of Zero Net Charge The pointof zero net charge (PZNC) the pH at which net surfacecharge of the whole system (taking into account both per-manent and variable charge colloids) is zero was obtainedby interpolation of the data from the measurement of chargevariation with pH Charge variation with pHwas determinedby the fingerprint method of Gillman and Sumner [27]Two-gram air-dried soil samples in 50mL preweighed plasticcentrifuge tubes were shaken with 20mL of 01MCaCl
2
for 2 h to saturate the soil with Ca The suspension was
Applied and Environmental Soil Science 3
Table 1 General information on the studied pedons
Pedon Soil classification Relief Physiography Land use Parent material Drainage
1Fine loamy mixed(calcareous) hyperthermicCalcic Haplosalids
Flat Piedmont alluvialplain Saline pasture Calcareous alluvium Imperfectly drained
2Coarse loamy mixed(calcareous) hyperthermicAridic Ustorthents
Almost flat River alluvial plain Bare Calcareous alluvium Well drained
3Fine loamy mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Plowed Calcareous alluvium Moderately well
drained
4Loamy skeletal mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Harvested wheat Calcareous alluvium Well drained
5Sandy skeletal mixed(calcareous) hyperthermicAridic Ustifluvents
Almost steep Alluvial-colluvialfan pasture Calcareous alluvium Well drained
6Coarse loamy mixed(calcareous) hyperthermicAridic Ustorthents
Flat River alluvial plain Plowed Calcareous alluvium Moderately welldrained
7Fine loamy mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Plowed Calcareous alluvium Well drained
8Sandy skeletal mixed(calcareous) hyperthermicAridic Ustorthents
Almost steep Alluvial-colluvialfan Pasture Calcareous alluvium Well drained
centrifuged (3000 rpm 10min) and the supernatant wasdiscardedTheCa saturated soil waswashed twicewith 20mLof 0002MCaCl
2and after the third addition of 20mL of
0002MCaCl2soil suspension was recorded and thereafter
the pH was adjusted to different values by dropwise additionof 01MHCl or saturated Ca(OH)
2 The equilibration of the
pH took several days After the pH was stable the suspen-sion was centrifuged and the supernatant was collected todetermine Ca Al and Cl in the entrained solution Thetubes were then weighed to estimate the volume of entrained0002MCaCl
2
The soil was then extracted with 20mL of 1m NH4NO3
and Ca Al and Cl were determined in the extract Allowingfor entrained Ca Al and Cl the amounts of cation (Ca2+ +Al3+) and anion (Clminus) adsorbed were calculated and equatedwith total negative (CECT) and positive (AEC) chargerespectively The amount of Ca adsorbed was equated withbasic cation exchange capacity (CECB) Aluminum and Cawere determined by AAS and Cl measured by silver nitratetitration method [28] The PZNC was identified as the pHvalue where total negative and positive charges are equalThepermanent charge was estimated as the difference betweenAEC and CECT values at pH
0[29]
224 Mineralogical Analyses Removal of chemical cement-ing agents and separation of the different size fractions ofsoils were carried out according to Mehra and Jackson [21]Kittrick and Hope [30] and Jackson [31] Organic matterand carbonate were removed with 30 H
2O2and 1NHCl
respectively X-ray diffraction (XRD) studies were carriedout on both fine and coarse clay fractions while equalconcentrations of clay suspensions were used for all samplesin order to allow for a more reliable comparison betweenrelative peak intensities for different samples Two drops ofthe prepared suspension were used on each glass slide Theclay samples were finally examined by XRD analysis usinga Philips diffractometer with Co K120572 radiation in order toallow for a more reliable comparison between the relativeheights of peaks in the XRD data The K-saturated sampleswere studied both after drying and heating at 500∘C for4 h to identify kaolinite in the presence of trioctahedralchlorite and samples were also treated with 1NHCl at 80∘Covernight Semiquantitative estimation of clay minerals wasmade by directly converting the diffraction peak areas usingthe method of Karanthanasis and Hajek [32] Selected driedclay particles of the soils were studied under a transmissionelectron microscope (TEM LEO 912 AB) The samplesdispersed in 100 alcohol and 100 120583L of the suspension wasdropped on formvar-coated Cu grids
The soil chemical and mineralogical properties and theirrelationship with the surface charge characteristics wereanalyzed by multiple and simple linear regression using SASand Excel softwares
3 Results and Discussion
31 Field Observation and Soil Classification The soil chem-ical data are shown in Table 1 Pedons 1 3 7 and 4 are soilsdeveloped on the piedmont alluvial plains while pedon 2
4 Applied and Environmental Soil Science
Table 2 Some physical properties of the representative profiles
Soil number Depth (cm) Clay Silt Sand Texture+ Structurelowast 120588119887(g cmminus3) Gravel ()
()
1
0ndash25 34 56 10 SiCL WP 154 mdash25ndash78 14 36 50 L Ma 150 mdash78ndash110 32 48 20 CL WG 153 mdash100ndash150 12 22 66 SL Ma 151 mdash
2
0ndash20 10 40 50 L WP 152 mdash20ndash50 10 8 82 LS Sg 153 mdash50ndash100 12 16 72 SL Sg nd 35100ndash150 8 2 90 S Sg 136 mdash
30ndash30 18 38 44 L WG 144 mdash30ndash80 16 37 47 L WG 140 mdash80ndash150 16 12 72 SL Sg 149 mdash
4
0ndash20 10 16 74 SL Sg nd 3020ndash70 8 16 76 SL Sg nd 5070ndash95 14 12 74 SL Sg nd 1095ndash150 12 4 84 LS Sg nd 50
5 0ndash45 18 20 62 SL Sg nd 8545ndash150 24 20 56 SiL Sg nd 65
60ndash42 16 34 50 L WG 141 mdash42ndash88 10 12 78 SL Ma 137 mdash88ndash150 12 26 62 SL Ma 141 mdash
70ndash36 24 42 34 L WG 135 mdash36ndash86 30 50 20 CL WG 139 mdash86ndash150 26 38 36 L WG 141 mdash
80ndash30 12 14 74 SL Sg nd 7030ndash70 10 8 82 LS Sg nd 7570ndash150 14 14 72 SL Sg nd 80
Texture+ SL sandy loam LS loamy sand L loam S sand SiL silty loam SiCL silty clay loam Structurelowast Ma massive Sg single grain WP weak platy WGweak granular nd no determine
and 6 are formed on river alluvial plains Pedons 5 and 8are formed on alluvial colluvial fans and sited on a higherslope area All pedons were dug with a maximum depth of150 cm and obvious textural changes throughout the profilewere observed Since the plain is part of an alluvial andcolluvial fan the deposition of materials from the alluvialand colluvial wash varies from time to time creating differenttextural layers This was observed in all the soils studiedwhere the soils textural changes were extreme particularlyfor the silt and sand content There were also variations intheir structures which is also associated with the amountof sand and silt in the soils The soils tend to be massivewhen the silt content is high otherwise the structures wouldbe single grain when the sand content is high The roundednature of these gravels suggests that they were washed anddeposited along part of the plain All soils were weaklydeveloped and evidenced by weak horizon formation in theprofiles Under the arid environment with annual precipita-tion value of less than 200mm and evaporation of more than4000mm one would surely expect to see slow rate of soilpedological development because of very low rate of PET0[33]
The eight representative profiles were classified usingthe USDA Soil Taxonomy [18] All soils are young anddifferentiated by their moisture regime They were identifiedas Calcic Haplosalids Aridic Ustorthents and Aridic Ustiflu-vents (Table 1)
32 Physical Properties The soil physical data are presentedin Table 2 None of the soil physical characteristics showany clear trend with depth In pedon 1 the clay contentdistribution was irregular In pedons 4 5 7 and 8 clayincreases with depths while in pedon 2 it increased onlyuntil the top 100 cm In contrast to the above observationspedon 6 exhibits a remarkable decrease in clay content withsoil depth In pedons 3 and 4 the silt content decreases withdepth The sand size particles are dominant in all pedonsexcept for pedons 1 and 7 but their distribution throughoutthe profile was very irregular The results are consistent withthe nature of alluvial and colluvial deposition that variesfrom time to time Khresat and Qudah [34] also observeda similar deposition trend on studying the Azraq Basin inNortheastern Jordan which is also formed from alluvial andcolluvial deposition
Applied and Environmental Soil Science 5
33 Chemical Properties The soil chemical data of the repre-sentative profiles are presented in Table 3 The soils are alka-line and calcareous in nature containing 1983 to 6145CaCO
3throughout the profiles All soils have pH values
above 70 showing that they are alkalineThe average electricalconductivity values exhibited some variations among the soilsstudied placing these soils from slightly saline to saline levelIn pedons 2 4 5 and 8 the soils were noted to be nonsalinewith EC values ranging from 04 to 264 dSmminus1 while soils inpedons 3 6 and 7 were slightly saline with EC values rangingfrom 21 to 7 dSmminus1 Pedon 1 soil was observed to be salinewith EC values ranging from 1811 to 305 dSmminus1 The Nacontent showed slight variability among the soils studied Inpedons 2 5 and 8 the amount of Na was between 04 and68 cmolckg
minus1 as compared to pedons 1 3 4 6 and 7 whichNa ranges between 184 in 20 cmolckg
minus1 The soils howeverare nonsodic with SAR values ranging from 03 to 77 Thecation exchange capacity ranges from 17 to 414 cmolckg
minus1In pedons 1 3 6 and 7 the CEC was between 195 and411 cmolckg
minus1 as compared to pedons 2 4 5 and 8 withvalues of 117 to 215 The organic carbon content was low inall soils which is common for soils of these regions where thevegetation is scarce
The variability of the soil chemical properties againreflects the alluvial and colluvial nature of soil deposition andtheir rocks origin According to Navai [35] the predominantrocks surrounding the study area are limestone dolomite(Jahrom Formation) limestone marl (Aghajari Formation)limestone green marl (Mishan Formation) salt domes (Hor-moze Formation) and conglomerate (Bakhtiari Formation)The weathered rock materials from these formations werewashed to the catchment areas and these contributed to thevariability in the soil physicochemical properties
34 Clay Mineralogy The clay minerals of the examinedsoils are presented in Table 4 Based on 119889-spacing theminerals identified through XRD diffractograms are as fol-lows smectite (1402ndash15 318ndash320 A) palygorskite (104ndash106 634ndash64 323 and 425ndash447 A) chlorite (701ndash711353 A) illite (997ndash1009 498ndash502 A) kaolinite (72ndash73228 A) and sepiolite (1210ndash1211) The presence of smectitewas proven by Mg-saturated clay samples solvated by ethy-lene glycole which expanded due to treatment with Mg-saturated
The common minerals in all samples of the studied areaare smectite palygorskite illite chlorite and kaolinite Kaoli-nite is found in all soils with the exception of pedon 8 Sepi-olite exists in pedons 3 4 6 and 7 The dominance of theseminerals in the arid regions agrees with the results obtainedby Owliaie et al [36] and Emadi et al [37] Palygorskiteand sepiolite are fibrous clays and are considered to be ofauthigenic origin inherited from weathered parent materialsof the surrounding hills and plateaus [33] The presence ofkaolinite inmost soils is probably due to inheritance from theweathering of coarse and fine materials transported from thesurrounding upland zones Itmay also suggest the occurrenceof palygorskite and sepiolite kaolinization that apparentlymay be due to the effect of organic matter decomposition and
fibrous clay destabilization caused by Mg uptake by plants[38]
35 Soil Electrochemical Properties
351 Point of Zero Charge Characteristics The pH0values
varied from 28 in subsurface horizon of pedon 2 to 335 inthe topsoil horizon of pedon 1 (Table 4) and were positivelycorrelated with the Fed content (119903 = 087
lowastlowast 119875 lt 001) whichwas far more than its correlation with the OC percentage (119903 =minus083
lowastlowast 119875 lt 001) The pH0also has a negative significant
correlation with pHH2O (119903 = minus045lowast 119875 lt 005) Hence the
Fed content had more effect on pH0values compared with
theOC content in the soils studiedThe respective pH0values
of organic matter and sesquioxides have been reported todecrease and increase respectively [8 39]
Li and Xu [40] reported that the layer silicate clays (2 1clays) decreased the pH
0values while the 1 1 clay minerals
as kaolinite increased the pH0 Besides Uehara and Gillman
[5] reported that the oxides of Fe andAl have high pH0values
(pH 7ndash9) while silica (SiO2) and organicmatter have low pH
0
values Therefore the low levels of pH0in the present study
were probably related to layer silicate clays (2 1 clays) andhigh pH in all the pedons
The values of 120575pH (pH0minus pHCaCl
2
) indicate the evolutionof positive and negative charges on the variable chargecomponents [11] The greatest values of 120575pH (pH
0minus pHCaCl
2
)were related to subsurface horizon of profile 2 (minus510 units)which agreed with its strongly negative net charge in the fieldconditions (Table 4) The mineralogical data also confirmedthe occurrence of significant amounts of layer silicate min-erals (smectitic type) in this profile (Table 4) Generally thevariations of 120575pH (pH
0minuspHCaCl
2
) for all the studied horizonsshowed a rather high level (between minus425 and minus510 units)(Table 4) which was in accordance with their CEC levels(Table 3) However because of a large quantity of layer silicateminerals (2 1 clays) and a scarcity of 1 1 clays and Fed thisrising trend from surface to subsurface horizons was not sonoticeable
352 Point of Zero Net Charge (PZNC) For all the studiedsoils the PZNC levels were lt2 which was probably due tothe excess negative charge in these soils Gonzales-Batista etal [10] reported that for systems free of permanent chargePZNC should coincide with pH
0 but for systems where
permanent and variable charges coexist PZNC may differfrom pH
0 Usually in the young soils (Entisols or Inceptisols)
PZNC is lower than its pH0and higher than pH
0if the soils
are highly weathered such as Oxisols [41] In addition themodel of Uehara and Gillman [11] and Yu [2] predict thatin soils having constant negative charge the PZNC value islower than pH
0and vice versa None of the charge variation
curves of the samples indicated the PZNC in pH betweenranges of 26 and 6 which was due to the excessive amountof negative charge compared with the positive charge inthese ranges of pH Besides the amount of estimated ZPNCin all the samples was lower than the pH
0 confirming the
presence of the permanent negative charge in these soils
6 Applied and Environmental Soil Science
Table3Ch
emicalprop
ertie
softhe
representativ
eprofiles
Soilnu
mber
Depth
(cm)
pHCa
Cl2
pHH2O
pHKC
lΔpH
(KClminusH
2O)
OC
SAR
CCE
EC dSmminus1
CEC
K+Na+
Mg2
+Ca2
+
Fed(
)(125)
cmol
ckgminus
1
1
0ndash25
765
779
760
minus019
034
742137
2985
414
067
2085
65
016
25ndash78
760
776
755
minus021
020
702498
275
263
022
1445
35
015
78ndash110
755
768
750
minus018
023
66
1983
325
334
036
1672
43
014
100ndash
150
770
787
762
minus025
012
772370
1811
313
017
154
52
33
015
2
0ndash20
785
797
780
minus017
018
36
2704
096
215
023
68
48
25
009
20ndash50
790
803
786
minus017
014
37
2755
040
182
022
57
46
22
010
50ndash100
780
795
773
minus022
013
182832
120
154
020
34
43
24
009
100ndash
150
790
794
774
minus020
016
07
2446
093
117
017
1417
23
010
30ndash
3077
579
077
0minus020
037
35
515
428
233
040
7767
28
011
30ndash80
779
793
774
minus019
020
46
5716
700
347
025
121
1032
013
80ndash150
783
797
778
minus021
017
45
5897
548
295
022
108
837
009
4
0ndash20
785
794
780
minus014
033
24
2884
264
176
051
52
47
53
010
20ndash70
793
802
792
minus010
035
30
2885
145
161
018
52
1346
012
70ndash9
578
079
277
5minus017
030
102729
103
144
018
184
1548
011
95ndash150
794
801
790
minus011
043
162798
121
117
015
26
08
43
015
50ndash
4577
578
8772
minus016
035
155820
154
151
021
28
06
65
012
45ndash150
790
804
785
minus019
038
03
5645
037
132
020
04
05
64
013
60ndash
4277
879
771
minus019
029
39
2824
516
275
039
9766
65
009
42ndash88
790
808
786
minus022
033
26
2353
210
195
017
57
48
50
011
88ndash150
789
806
787
minus019
016
48
2536
492
258
023
108
58
45
012
70ndash
3676
878
175
7minus024
037
29
6145
455
243
022
69
51
67
010
36ndash86
780
795
772
minus023
039
21
6041
525
267
024
54
61
64
009
86ndash150
784
798
780
minus018
029
29
6067
496
258
026
7589
45
010
80ndash
3078
079
1776
minus015
024
22
3112
057
168
036
426
43
009
30ndash70
785
789
783
minus006
025
21
3190
080
184
024
38
22
48
006
70ndash150
781
785
778
minus007
026
33
285
066
175
018
627
43
007
OC
organicc
arbo
nSA
Rsodium
adsorptio
nratio
CEC
cationexchange
capacityFe ddith
ionitecitrateb
icarbo
nateC
CEcalcium
carbon
atee
quivalentEC
electric
alcond
uctiv
ity
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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EcologyInternational Journal of
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Marine BiologyJournal of
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Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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BiodiversityInternational Journal of
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OceanographyInternational Journal of
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
Applied and Environmental Soil Science 3
Table 1 General information on the studied pedons
Pedon Soil classification Relief Physiography Land use Parent material Drainage
1Fine loamy mixed(calcareous) hyperthermicCalcic Haplosalids
Flat Piedmont alluvialplain Saline pasture Calcareous alluvium Imperfectly drained
2Coarse loamy mixed(calcareous) hyperthermicAridic Ustorthents
Almost flat River alluvial plain Bare Calcareous alluvium Well drained
3Fine loamy mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Plowed Calcareous alluvium Moderately well
drained
4Loamy skeletal mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Harvested wheat Calcareous alluvium Well drained
5Sandy skeletal mixed(calcareous) hyperthermicAridic Ustifluvents
Almost steep Alluvial-colluvialfan pasture Calcareous alluvium Well drained
6Coarse loamy mixed(calcareous) hyperthermicAridic Ustorthents
Flat River alluvial plain Plowed Calcareous alluvium Moderately welldrained
7Fine loamy mixed(calcareous) hyperthermicAridic Ustifluvents
Almost flat Piedmont alluvialplain Plowed Calcareous alluvium Well drained
8Sandy skeletal mixed(calcareous) hyperthermicAridic Ustorthents
Almost steep Alluvial-colluvialfan Pasture Calcareous alluvium Well drained
centrifuged (3000 rpm 10min) and the supernatant wasdiscardedTheCa saturated soil waswashed twicewith 20mLof 0002MCaCl
2and after the third addition of 20mL of
0002MCaCl2soil suspension was recorded and thereafter
the pH was adjusted to different values by dropwise additionof 01MHCl or saturated Ca(OH)
2 The equilibration of the
pH took several days After the pH was stable the suspen-sion was centrifuged and the supernatant was collected todetermine Ca Al and Cl in the entrained solution Thetubes were then weighed to estimate the volume of entrained0002MCaCl
2
The soil was then extracted with 20mL of 1m NH4NO3
and Ca Al and Cl were determined in the extract Allowingfor entrained Ca Al and Cl the amounts of cation (Ca2+ +Al3+) and anion (Clminus) adsorbed were calculated and equatedwith total negative (CECT) and positive (AEC) chargerespectively The amount of Ca adsorbed was equated withbasic cation exchange capacity (CECB) Aluminum and Cawere determined by AAS and Cl measured by silver nitratetitration method [28] The PZNC was identified as the pHvalue where total negative and positive charges are equalThepermanent charge was estimated as the difference betweenAEC and CECT values at pH
0[29]
224 Mineralogical Analyses Removal of chemical cement-ing agents and separation of the different size fractions ofsoils were carried out according to Mehra and Jackson [21]Kittrick and Hope [30] and Jackson [31] Organic matterand carbonate were removed with 30 H
2O2and 1NHCl
respectively X-ray diffraction (XRD) studies were carriedout on both fine and coarse clay fractions while equalconcentrations of clay suspensions were used for all samplesin order to allow for a more reliable comparison betweenrelative peak intensities for different samples Two drops ofthe prepared suspension were used on each glass slide Theclay samples were finally examined by XRD analysis usinga Philips diffractometer with Co K120572 radiation in order toallow for a more reliable comparison between the relativeheights of peaks in the XRD data The K-saturated sampleswere studied both after drying and heating at 500∘C for4 h to identify kaolinite in the presence of trioctahedralchlorite and samples were also treated with 1NHCl at 80∘Covernight Semiquantitative estimation of clay minerals wasmade by directly converting the diffraction peak areas usingthe method of Karanthanasis and Hajek [32] Selected driedclay particles of the soils were studied under a transmissionelectron microscope (TEM LEO 912 AB) The samplesdispersed in 100 alcohol and 100 120583L of the suspension wasdropped on formvar-coated Cu grids
The soil chemical and mineralogical properties and theirrelationship with the surface charge characteristics wereanalyzed by multiple and simple linear regression using SASand Excel softwares
3 Results and Discussion
31 Field Observation and Soil Classification The soil chem-ical data are shown in Table 1 Pedons 1 3 7 and 4 are soilsdeveloped on the piedmont alluvial plains while pedon 2
4 Applied and Environmental Soil Science
Table 2 Some physical properties of the representative profiles
Soil number Depth (cm) Clay Silt Sand Texture+ Structurelowast 120588119887(g cmminus3) Gravel ()
()
1
0ndash25 34 56 10 SiCL WP 154 mdash25ndash78 14 36 50 L Ma 150 mdash78ndash110 32 48 20 CL WG 153 mdash100ndash150 12 22 66 SL Ma 151 mdash
2
0ndash20 10 40 50 L WP 152 mdash20ndash50 10 8 82 LS Sg 153 mdash50ndash100 12 16 72 SL Sg nd 35100ndash150 8 2 90 S Sg 136 mdash
30ndash30 18 38 44 L WG 144 mdash30ndash80 16 37 47 L WG 140 mdash80ndash150 16 12 72 SL Sg 149 mdash
4
0ndash20 10 16 74 SL Sg nd 3020ndash70 8 16 76 SL Sg nd 5070ndash95 14 12 74 SL Sg nd 1095ndash150 12 4 84 LS Sg nd 50
5 0ndash45 18 20 62 SL Sg nd 8545ndash150 24 20 56 SiL Sg nd 65
60ndash42 16 34 50 L WG 141 mdash42ndash88 10 12 78 SL Ma 137 mdash88ndash150 12 26 62 SL Ma 141 mdash
70ndash36 24 42 34 L WG 135 mdash36ndash86 30 50 20 CL WG 139 mdash86ndash150 26 38 36 L WG 141 mdash
80ndash30 12 14 74 SL Sg nd 7030ndash70 10 8 82 LS Sg nd 7570ndash150 14 14 72 SL Sg nd 80
Texture+ SL sandy loam LS loamy sand L loam S sand SiL silty loam SiCL silty clay loam Structurelowast Ma massive Sg single grain WP weak platy WGweak granular nd no determine
and 6 are formed on river alluvial plains Pedons 5 and 8are formed on alluvial colluvial fans and sited on a higherslope area All pedons were dug with a maximum depth of150 cm and obvious textural changes throughout the profilewere observed Since the plain is part of an alluvial andcolluvial fan the deposition of materials from the alluvialand colluvial wash varies from time to time creating differenttextural layers This was observed in all the soils studiedwhere the soils textural changes were extreme particularlyfor the silt and sand content There were also variations intheir structures which is also associated with the amountof sand and silt in the soils The soils tend to be massivewhen the silt content is high otherwise the structures wouldbe single grain when the sand content is high The roundednature of these gravels suggests that they were washed anddeposited along part of the plain All soils were weaklydeveloped and evidenced by weak horizon formation in theprofiles Under the arid environment with annual precipita-tion value of less than 200mm and evaporation of more than4000mm one would surely expect to see slow rate of soilpedological development because of very low rate of PET0[33]
The eight representative profiles were classified usingthe USDA Soil Taxonomy [18] All soils are young anddifferentiated by their moisture regime They were identifiedas Calcic Haplosalids Aridic Ustorthents and Aridic Ustiflu-vents (Table 1)
32 Physical Properties The soil physical data are presentedin Table 2 None of the soil physical characteristics showany clear trend with depth In pedon 1 the clay contentdistribution was irregular In pedons 4 5 7 and 8 clayincreases with depths while in pedon 2 it increased onlyuntil the top 100 cm In contrast to the above observationspedon 6 exhibits a remarkable decrease in clay content withsoil depth In pedons 3 and 4 the silt content decreases withdepth The sand size particles are dominant in all pedonsexcept for pedons 1 and 7 but their distribution throughoutthe profile was very irregular The results are consistent withthe nature of alluvial and colluvial deposition that variesfrom time to time Khresat and Qudah [34] also observeda similar deposition trend on studying the Azraq Basin inNortheastern Jordan which is also formed from alluvial andcolluvial deposition
Applied and Environmental Soil Science 5
33 Chemical Properties The soil chemical data of the repre-sentative profiles are presented in Table 3 The soils are alka-line and calcareous in nature containing 1983 to 6145CaCO
3throughout the profiles All soils have pH values
above 70 showing that they are alkalineThe average electricalconductivity values exhibited some variations among the soilsstudied placing these soils from slightly saline to saline levelIn pedons 2 4 5 and 8 the soils were noted to be nonsalinewith EC values ranging from 04 to 264 dSmminus1 while soils inpedons 3 6 and 7 were slightly saline with EC values rangingfrom 21 to 7 dSmminus1 Pedon 1 soil was observed to be salinewith EC values ranging from 1811 to 305 dSmminus1 The Nacontent showed slight variability among the soils studied Inpedons 2 5 and 8 the amount of Na was between 04 and68 cmolckg
minus1 as compared to pedons 1 3 4 6 and 7 whichNa ranges between 184 in 20 cmolckg
minus1 The soils howeverare nonsodic with SAR values ranging from 03 to 77 Thecation exchange capacity ranges from 17 to 414 cmolckg
minus1In pedons 1 3 6 and 7 the CEC was between 195 and411 cmolckg
minus1 as compared to pedons 2 4 5 and 8 withvalues of 117 to 215 The organic carbon content was low inall soils which is common for soils of these regions where thevegetation is scarce
The variability of the soil chemical properties againreflects the alluvial and colluvial nature of soil deposition andtheir rocks origin According to Navai [35] the predominantrocks surrounding the study area are limestone dolomite(Jahrom Formation) limestone marl (Aghajari Formation)limestone green marl (Mishan Formation) salt domes (Hor-moze Formation) and conglomerate (Bakhtiari Formation)The weathered rock materials from these formations werewashed to the catchment areas and these contributed to thevariability in the soil physicochemical properties
34 Clay Mineralogy The clay minerals of the examinedsoils are presented in Table 4 Based on 119889-spacing theminerals identified through XRD diffractograms are as fol-lows smectite (1402ndash15 318ndash320 A) palygorskite (104ndash106 634ndash64 323 and 425ndash447 A) chlorite (701ndash711353 A) illite (997ndash1009 498ndash502 A) kaolinite (72ndash73228 A) and sepiolite (1210ndash1211) The presence of smectitewas proven by Mg-saturated clay samples solvated by ethy-lene glycole which expanded due to treatment with Mg-saturated
The common minerals in all samples of the studied areaare smectite palygorskite illite chlorite and kaolinite Kaoli-nite is found in all soils with the exception of pedon 8 Sepi-olite exists in pedons 3 4 6 and 7 The dominance of theseminerals in the arid regions agrees with the results obtainedby Owliaie et al [36] and Emadi et al [37] Palygorskiteand sepiolite are fibrous clays and are considered to be ofauthigenic origin inherited from weathered parent materialsof the surrounding hills and plateaus [33] The presence ofkaolinite inmost soils is probably due to inheritance from theweathering of coarse and fine materials transported from thesurrounding upland zones Itmay also suggest the occurrenceof palygorskite and sepiolite kaolinization that apparentlymay be due to the effect of organic matter decomposition and
fibrous clay destabilization caused by Mg uptake by plants[38]
35 Soil Electrochemical Properties
351 Point of Zero Charge Characteristics The pH0values
varied from 28 in subsurface horizon of pedon 2 to 335 inthe topsoil horizon of pedon 1 (Table 4) and were positivelycorrelated with the Fed content (119903 = 087
lowastlowast 119875 lt 001) whichwas far more than its correlation with the OC percentage (119903 =minus083
lowastlowast 119875 lt 001) The pH0also has a negative significant
correlation with pHH2O (119903 = minus045lowast 119875 lt 005) Hence the
Fed content had more effect on pH0values compared with
theOC content in the soils studiedThe respective pH0values
of organic matter and sesquioxides have been reported todecrease and increase respectively [8 39]
Li and Xu [40] reported that the layer silicate clays (2 1clays) decreased the pH
0values while the 1 1 clay minerals
as kaolinite increased the pH0 Besides Uehara and Gillman
[5] reported that the oxides of Fe andAl have high pH0values
(pH 7ndash9) while silica (SiO2) and organicmatter have low pH
0
values Therefore the low levels of pH0in the present study
were probably related to layer silicate clays (2 1 clays) andhigh pH in all the pedons
The values of 120575pH (pH0minus pHCaCl
2
) indicate the evolutionof positive and negative charges on the variable chargecomponents [11] The greatest values of 120575pH (pH
0minus pHCaCl
2
)were related to subsurface horizon of profile 2 (minus510 units)which agreed with its strongly negative net charge in the fieldconditions (Table 4) The mineralogical data also confirmedthe occurrence of significant amounts of layer silicate min-erals (smectitic type) in this profile (Table 4) Generally thevariations of 120575pH (pH
0minuspHCaCl
2
) for all the studied horizonsshowed a rather high level (between minus425 and minus510 units)(Table 4) which was in accordance with their CEC levels(Table 3) However because of a large quantity of layer silicateminerals (2 1 clays) and a scarcity of 1 1 clays and Fed thisrising trend from surface to subsurface horizons was not sonoticeable
352 Point of Zero Net Charge (PZNC) For all the studiedsoils the PZNC levels were lt2 which was probably due tothe excess negative charge in these soils Gonzales-Batista etal [10] reported that for systems free of permanent chargePZNC should coincide with pH
0 but for systems where
permanent and variable charges coexist PZNC may differfrom pH
0 Usually in the young soils (Entisols or Inceptisols)
PZNC is lower than its pH0and higher than pH
0if the soils
are highly weathered such as Oxisols [41] In addition themodel of Uehara and Gillman [11] and Yu [2] predict thatin soils having constant negative charge the PZNC value islower than pH
0and vice versa None of the charge variation
curves of the samples indicated the PZNC in pH betweenranges of 26 and 6 which was due to the excessive amountof negative charge compared with the positive charge inthese ranges of pH Besides the amount of estimated ZPNCin all the samples was lower than the pH
0 confirming the
presence of the permanent negative charge in these soils
6 Applied and Environmental Soil Science
Table3Ch
emicalprop
ertie
softhe
representativ
eprofiles
Soilnu
mber
Depth
(cm)
pHCa
Cl2
pHH2O
pHKC
lΔpH
(KClminusH
2O)
OC
SAR
CCE
EC dSmminus1
CEC
K+Na+
Mg2
+Ca2
+
Fed(
)(125)
cmol
ckgminus
1
1
0ndash25
765
779
760
minus019
034
742137
2985
414
067
2085
65
016
25ndash78
760
776
755
minus021
020
702498
275
263
022
1445
35
015
78ndash110
755
768
750
minus018
023
66
1983
325
334
036
1672
43
014
100ndash
150
770
787
762
minus025
012
772370
1811
313
017
154
52
33
015
2
0ndash20
785
797
780
minus017
018
36
2704
096
215
023
68
48
25
009
20ndash50
790
803
786
minus017
014
37
2755
040
182
022
57
46
22
010
50ndash100
780
795
773
minus022
013
182832
120
154
020
34
43
24
009
100ndash
150
790
794
774
minus020
016
07
2446
093
117
017
1417
23
010
30ndash
3077
579
077
0minus020
037
35
515
428
233
040
7767
28
011
30ndash80
779
793
774
minus019
020
46
5716
700
347
025
121
1032
013
80ndash150
783
797
778
minus021
017
45
5897
548
295
022
108
837
009
4
0ndash20
785
794
780
minus014
033
24
2884
264
176
051
52
47
53
010
20ndash70
793
802
792
minus010
035
30
2885
145
161
018
52
1346
012
70ndash9
578
079
277
5minus017
030
102729
103
144
018
184
1548
011
95ndash150
794
801
790
minus011
043
162798
121
117
015
26
08
43
015
50ndash
4577
578
8772
minus016
035
155820
154
151
021
28
06
65
012
45ndash150
790
804
785
minus019
038
03
5645
037
132
020
04
05
64
013
60ndash
4277
879
771
minus019
029
39
2824
516
275
039
9766
65
009
42ndash88
790
808
786
minus022
033
26
2353
210
195
017
57
48
50
011
88ndash150
789
806
787
minus019
016
48
2536
492
258
023
108
58
45
012
70ndash
3676
878
175
7minus024
037
29
6145
455
243
022
69
51
67
010
36ndash86
780
795
772
minus023
039
21
6041
525
267
024
54
61
64
009
86ndash150
784
798
780
minus018
029
29
6067
496
258
026
7589
45
010
80ndash
3078
079
1776
minus015
024
22
3112
057
168
036
426
43
009
30ndash70
785
789
783
minus006
025
21
3190
080
184
024
38
22
48
006
70ndash150
781
785
778
minus007
026
33
285
066
175
018
627
43
007
OC
organicc
arbo
nSA
Rsodium
adsorptio
nratio
CEC
cationexchange
capacityFe ddith
ionitecitrateb
icarbo
nateC
CEcalcium
carbon
atee
quivalentEC
electric
alcond
uctiv
ity
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
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ClimatologyJournal of
4 Applied and Environmental Soil Science
Table 2 Some physical properties of the representative profiles
Soil number Depth (cm) Clay Silt Sand Texture+ Structurelowast 120588119887(g cmminus3) Gravel ()
()
1
0ndash25 34 56 10 SiCL WP 154 mdash25ndash78 14 36 50 L Ma 150 mdash78ndash110 32 48 20 CL WG 153 mdash100ndash150 12 22 66 SL Ma 151 mdash
2
0ndash20 10 40 50 L WP 152 mdash20ndash50 10 8 82 LS Sg 153 mdash50ndash100 12 16 72 SL Sg nd 35100ndash150 8 2 90 S Sg 136 mdash
30ndash30 18 38 44 L WG 144 mdash30ndash80 16 37 47 L WG 140 mdash80ndash150 16 12 72 SL Sg 149 mdash
4
0ndash20 10 16 74 SL Sg nd 3020ndash70 8 16 76 SL Sg nd 5070ndash95 14 12 74 SL Sg nd 1095ndash150 12 4 84 LS Sg nd 50
5 0ndash45 18 20 62 SL Sg nd 8545ndash150 24 20 56 SiL Sg nd 65
60ndash42 16 34 50 L WG 141 mdash42ndash88 10 12 78 SL Ma 137 mdash88ndash150 12 26 62 SL Ma 141 mdash
70ndash36 24 42 34 L WG 135 mdash36ndash86 30 50 20 CL WG 139 mdash86ndash150 26 38 36 L WG 141 mdash
80ndash30 12 14 74 SL Sg nd 7030ndash70 10 8 82 LS Sg nd 7570ndash150 14 14 72 SL Sg nd 80
Texture+ SL sandy loam LS loamy sand L loam S sand SiL silty loam SiCL silty clay loam Structurelowast Ma massive Sg single grain WP weak platy WGweak granular nd no determine
and 6 are formed on river alluvial plains Pedons 5 and 8are formed on alluvial colluvial fans and sited on a higherslope area All pedons were dug with a maximum depth of150 cm and obvious textural changes throughout the profilewere observed Since the plain is part of an alluvial andcolluvial fan the deposition of materials from the alluvialand colluvial wash varies from time to time creating differenttextural layers This was observed in all the soils studiedwhere the soils textural changes were extreme particularlyfor the silt and sand content There were also variations intheir structures which is also associated with the amountof sand and silt in the soils The soils tend to be massivewhen the silt content is high otherwise the structures wouldbe single grain when the sand content is high The roundednature of these gravels suggests that they were washed anddeposited along part of the plain All soils were weaklydeveloped and evidenced by weak horizon formation in theprofiles Under the arid environment with annual precipita-tion value of less than 200mm and evaporation of more than4000mm one would surely expect to see slow rate of soilpedological development because of very low rate of PET0[33]
The eight representative profiles were classified usingthe USDA Soil Taxonomy [18] All soils are young anddifferentiated by their moisture regime They were identifiedas Calcic Haplosalids Aridic Ustorthents and Aridic Ustiflu-vents (Table 1)
32 Physical Properties The soil physical data are presentedin Table 2 None of the soil physical characteristics showany clear trend with depth In pedon 1 the clay contentdistribution was irregular In pedons 4 5 7 and 8 clayincreases with depths while in pedon 2 it increased onlyuntil the top 100 cm In contrast to the above observationspedon 6 exhibits a remarkable decrease in clay content withsoil depth In pedons 3 and 4 the silt content decreases withdepth The sand size particles are dominant in all pedonsexcept for pedons 1 and 7 but their distribution throughoutthe profile was very irregular The results are consistent withthe nature of alluvial and colluvial deposition that variesfrom time to time Khresat and Qudah [34] also observeda similar deposition trend on studying the Azraq Basin inNortheastern Jordan which is also formed from alluvial andcolluvial deposition
Applied and Environmental Soil Science 5
33 Chemical Properties The soil chemical data of the repre-sentative profiles are presented in Table 3 The soils are alka-line and calcareous in nature containing 1983 to 6145CaCO
3throughout the profiles All soils have pH values
above 70 showing that they are alkalineThe average electricalconductivity values exhibited some variations among the soilsstudied placing these soils from slightly saline to saline levelIn pedons 2 4 5 and 8 the soils were noted to be nonsalinewith EC values ranging from 04 to 264 dSmminus1 while soils inpedons 3 6 and 7 were slightly saline with EC values rangingfrom 21 to 7 dSmminus1 Pedon 1 soil was observed to be salinewith EC values ranging from 1811 to 305 dSmminus1 The Nacontent showed slight variability among the soils studied Inpedons 2 5 and 8 the amount of Na was between 04 and68 cmolckg
minus1 as compared to pedons 1 3 4 6 and 7 whichNa ranges between 184 in 20 cmolckg
minus1 The soils howeverare nonsodic with SAR values ranging from 03 to 77 Thecation exchange capacity ranges from 17 to 414 cmolckg
minus1In pedons 1 3 6 and 7 the CEC was between 195 and411 cmolckg
minus1 as compared to pedons 2 4 5 and 8 withvalues of 117 to 215 The organic carbon content was low inall soils which is common for soils of these regions where thevegetation is scarce
The variability of the soil chemical properties againreflects the alluvial and colluvial nature of soil deposition andtheir rocks origin According to Navai [35] the predominantrocks surrounding the study area are limestone dolomite(Jahrom Formation) limestone marl (Aghajari Formation)limestone green marl (Mishan Formation) salt domes (Hor-moze Formation) and conglomerate (Bakhtiari Formation)The weathered rock materials from these formations werewashed to the catchment areas and these contributed to thevariability in the soil physicochemical properties
34 Clay Mineralogy The clay minerals of the examinedsoils are presented in Table 4 Based on 119889-spacing theminerals identified through XRD diffractograms are as fol-lows smectite (1402ndash15 318ndash320 A) palygorskite (104ndash106 634ndash64 323 and 425ndash447 A) chlorite (701ndash711353 A) illite (997ndash1009 498ndash502 A) kaolinite (72ndash73228 A) and sepiolite (1210ndash1211) The presence of smectitewas proven by Mg-saturated clay samples solvated by ethy-lene glycole which expanded due to treatment with Mg-saturated
The common minerals in all samples of the studied areaare smectite palygorskite illite chlorite and kaolinite Kaoli-nite is found in all soils with the exception of pedon 8 Sepi-olite exists in pedons 3 4 6 and 7 The dominance of theseminerals in the arid regions agrees with the results obtainedby Owliaie et al [36] and Emadi et al [37] Palygorskiteand sepiolite are fibrous clays and are considered to be ofauthigenic origin inherited from weathered parent materialsof the surrounding hills and plateaus [33] The presence ofkaolinite inmost soils is probably due to inheritance from theweathering of coarse and fine materials transported from thesurrounding upland zones Itmay also suggest the occurrenceof palygorskite and sepiolite kaolinization that apparentlymay be due to the effect of organic matter decomposition and
fibrous clay destabilization caused by Mg uptake by plants[38]
35 Soil Electrochemical Properties
351 Point of Zero Charge Characteristics The pH0values
varied from 28 in subsurface horizon of pedon 2 to 335 inthe topsoil horizon of pedon 1 (Table 4) and were positivelycorrelated with the Fed content (119903 = 087
lowastlowast 119875 lt 001) whichwas far more than its correlation with the OC percentage (119903 =minus083
lowastlowast 119875 lt 001) The pH0also has a negative significant
correlation with pHH2O (119903 = minus045lowast 119875 lt 005) Hence the
Fed content had more effect on pH0values compared with
theOC content in the soils studiedThe respective pH0values
of organic matter and sesquioxides have been reported todecrease and increase respectively [8 39]
Li and Xu [40] reported that the layer silicate clays (2 1clays) decreased the pH
0values while the 1 1 clay minerals
as kaolinite increased the pH0 Besides Uehara and Gillman
[5] reported that the oxides of Fe andAl have high pH0values
(pH 7ndash9) while silica (SiO2) and organicmatter have low pH
0
values Therefore the low levels of pH0in the present study
were probably related to layer silicate clays (2 1 clays) andhigh pH in all the pedons
The values of 120575pH (pH0minus pHCaCl
2
) indicate the evolutionof positive and negative charges on the variable chargecomponents [11] The greatest values of 120575pH (pH
0minus pHCaCl
2
)were related to subsurface horizon of profile 2 (minus510 units)which agreed with its strongly negative net charge in the fieldconditions (Table 4) The mineralogical data also confirmedthe occurrence of significant amounts of layer silicate min-erals (smectitic type) in this profile (Table 4) Generally thevariations of 120575pH (pH
0minuspHCaCl
2
) for all the studied horizonsshowed a rather high level (between minus425 and minus510 units)(Table 4) which was in accordance with their CEC levels(Table 3) However because of a large quantity of layer silicateminerals (2 1 clays) and a scarcity of 1 1 clays and Fed thisrising trend from surface to subsurface horizons was not sonoticeable
352 Point of Zero Net Charge (PZNC) For all the studiedsoils the PZNC levels were lt2 which was probably due tothe excess negative charge in these soils Gonzales-Batista etal [10] reported that for systems free of permanent chargePZNC should coincide with pH
0 but for systems where
permanent and variable charges coexist PZNC may differfrom pH
0 Usually in the young soils (Entisols or Inceptisols)
PZNC is lower than its pH0and higher than pH
0if the soils
are highly weathered such as Oxisols [41] In addition themodel of Uehara and Gillman [11] and Yu [2] predict thatin soils having constant negative charge the PZNC value islower than pH
0and vice versa None of the charge variation
curves of the samples indicated the PZNC in pH betweenranges of 26 and 6 which was due to the excessive amountof negative charge compared with the positive charge inthese ranges of pH Besides the amount of estimated ZPNCin all the samples was lower than the pH
0 confirming the
presence of the permanent negative charge in these soils
6 Applied and Environmental Soil Science
Table3Ch
emicalprop
ertie
softhe
representativ
eprofiles
Soilnu
mber
Depth
(cm)
pHCa
Cl2
pHH2O
pHKC
lΔpH
(KClminusH
2O)
OC
SAR
CCE
EC dSmminus1
CEC
K+Na+
Mg2
+Ca2
+
Fed(
)(125)
cmol
ckgminus
1
1
0ndash25
765
779
760
minus019
034
742137
2985
414
067
2085
65
016
25ndash78
760
776
755
minus021
020
702498
275
263
022
1445
35
015
78ndash110
755
768
750
minus018
023
66
1983
325
334
036
1672
43
014
100ndash
150
770
787
762
minus025
012
772370
1811
313
017
154
52
33
015
2
0ndash20
785
797
780
minus017
018
36
2704
096
215
023
68
48
25
009
20ndash50
790
803
786
minus017
014
37
2755
040
182
022
57
46
22
010
50ndash100
780
795
773
minus022
013
182832
120
154
020
34
43
24
009
100ndash
150
790
794
774
minus020
016
07
2446
093
117
017
1417
23
010
30ndash
3077
579
077
0minus020
037
35
515
428
233
040
7767
28
011
30ndash80
779
793
774
minus019
020
46
5716
700
347
025
121
1032
013
80ndash150
783
797
778
minus021
017
45
5897
548
295
022
108
837
009
4
0ndash20
785
794
780
minus014
033
24
2884
264
176
051
52
47
53
010
20ndash70
793
802
792
minus010
035
30
2885
145
161
018
52
1346
012
70ndash9
578
079
277
5minus017
030
102729
103
144
018
184
1548
011
95ndash150
794
801
790
minus011
043
162798
121
117
015
26
08
43
015
50ndash
4577
578
8772
minus016
035
155820
154
151
021
28
06
65
012
45ndash150
790
804
785
minus019
038
03
5645
037
132
020
04
05
64
013
60ndash
4277
879
771
minus019
029
39
2824
516
275
039
9766
65
009
42ndash88
790
808
786
minus022
033
26
2353
210
195
017
57
48
50
011
88ndash150
789
806
787
minus019
016
48
2536
492
258
023
108
58
45
012
70ndash
3676
878
175
7minus024
037
29
6145
455
243
022
69
51
67
010
36ndash86
780
795
772
minus023
039
21
6041
525
267
024
54
61
64
009
86ndash150
784
798
780
minus018
029
29
6067
496
258
026
7589
45
010
80ndash
3078
079
1776
minus015
024
22
3112
057
168
036
426
43
009
30ndash70
785
789
783
minus006
025
21
3190
080
184
024
38
22
48
006
70ndash150
781
785
778
minus007
026
33
285
066
175
018
627
43
007
OC
organicc
arbo
nSA
Rsodium
adsorptio
nratio
CEC
cationexchange
capacityFe ddith
ionitecitrateb
icarbo
nateC
CEcalcium
carbon
atee
quivalentEC
electric
alcond
uctiv
ity
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
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MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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EarthquakesJournal of
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BiodiversityInternational Journal of
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ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
Applied and Environmental Soil Science 5
33 Chemical Properties The soil chemical data of the repre-sentative profiles are presented in Table 3 The soils are alka-line and calcareous in nature containing 1983 to 6145CaCO
3throughout the profiles All soils have pH values
above 70 showing that they are alkalineThe average electricalconductivity values exhibited some variations among the soilsstudied placing these soils from slightly saline to saline levelIn pedons 2 4 5 and 8 the soils were noted to be nonsalinewith EC values ranging from 04 to 264 dSmminus1 while soils inpedons 3 6 and 7 were slightly saline with EC values rangingfrom 21 to 7 dSmminus1 Pedon 1 soil was observed to be salinewith EC values ranging from 1811 to 305 dSmminus1 The Nacontent showed slight variability among the soils studied Inpedons 2 5 and 8 the amount of Na was between 04 and68 cmolckg
minus1 as compared to pedons 1 3 4 6 and 7 whichNa ranges between 184 in 20 cmolckg
minus1 The soils howeverare nonsodic with SAR values ranging from 03 to 77 Thecation exchange capacity ranges from 17 to 414 cmolckg
minus1In pedons 1 3 6 and 7 the CEC was between 195 and411 cmolckg
minus1 as compared to pedons 2 4 5 and 8 withvalues of 117 to 215 The organic carbon content was low inall soils which is common for soils of these regions where thevegetation is scarce
The variability of the soil chemical properties againreflects the alluvial and colluvial nature of soil deposition andtheir rocks origin According to Navai [35] the predominantrocks surrounding the study area are limestone dolomite(Jahrom Formation) limestone marl (Aghajari Formation)limestone green marl (Mishan Formation) salt domes (Hor-moze Formation) and conglomerate (Bakhtiari Formation)The weathered rock materials from these formations werewashed to the catchment areas and these contributed to thevariability in the soil physicochemical properties
34 Clay Mineralogy The clay minerals of the examinedsoils are presented in Table 4 Based on 119889-spacing theminerals identified through XRD diffractograms are as fol-lows smectite (1402ndash15 318ndash320 A) palygorskite (104ndash106 634ndash64 323 and 425ndash447 A) chlorite (701ndash711353 A) illite (997ndash1009 498ndash502 A) kaolinite (72ndash73228 A) and sepiolite (1210ndash1211) The presence of smectitewas proven by Mg-saturated clay samples solvated by ethy-lene glycole which expanded due to treatment with Mg-saturated
The common minerals in all samples of the studied areaare smectite palygorskite illite chlorite and kaolinite Kaoli-nite is found in all soils with the exception of pedon 8 Sepi-olite exists in pedons 3 4 6 and 7 The dominance of theseminerals in the arid regions agrees with the results obtainedby Owliaie et al [36] and Emadi et al [37] Palygorskiteand sepiolite are fibrous clays and are considered to be ofauthigenic origin inherited from weathered parent materialsof the surrounding hills and plateaus [33] The presence ofkaolinite inmost soils is probably due to inheritance from theweathering of coarse and fine materials transported from thesurrounding upland zones Itmay also suggest the occurrenceof palygorskite and sepiolite kaolinization that apparentlymay be due to the effect of organic matter decomposition and
fibrous clay destabilization caused by Mg uptake by plants[38]
35 Soil Electrochemical Properties
351 Point of Zero Charge Characteristics The pH0values
varied from 28 in subsurface horizon of pedon 2 to 335 inthe topsoil horizon of pedon 1 (Table 4) and were positivelycorrelated with the Fed content (119903 = 087
lowastlowast 119875 lt 001) whichwas far more than its correlation with the OC percentage (119903 =minus083
lowastlowast 119875 lt 001) The pH0also has a negative significant
correlation with pHH2O (119903 = minus045lowast 119875 lt 005) Hence the
Fed content had more effect on pH0values compared with
theOC content in the soils studiedThe respective pH0values
of organic matter and sesquioxides have been reported todecrease and increase respectively [8 39]
Li and Xu [40] reported that the layer silicate clays (2 1clays) decreased the pH
0values while the 1 1 clay minerals
as kaolinite increased the pH0 Besides Uehara and Gillman
[5] reported that the oxides of Fe andAl have high pH0values
(pH 7ndash9) while silica (SiO2) and organicmatter have low pH
0
values Therefore the low levels of pH0in the present study
were probably related to layer silicate clays (2 1 clays) andhigh pH in all the pedons
The values of 120575pH (pH0minus pHCaCl
2
) indicate the evolutionof positive and negative charges on the variable chargecomponents [11] The greatest values of 120575pH (pH
0minus pHCaCl
2
)were related to subsurface horizon of profile 2 (minus510 units)which agreed with its strongly negative net charge in the fieldconditions (Table 4) The mineralogical data also confirmedthe occurrence of significant amounts of layer silicate min-erals (smectitic type) in this profile (Table 4) Generally thevariations of 120575pH (pH
0minuspHCaCl
2
) for all the studied horizonsshowed a rather high level (between minus425 and minus510 units)(Table 4) which was in accordance with their CEC levels(Table 3) However because of a large quantity of layer silicateminerals (2 1 clays) and a scarcity of 1 1 clays and Fed thisrising trend from surface to subsurface horizons was not sonoticeable
352 Point of Zero Net Charge (PZNC) For all the studiedsoils the PZNC levels were lt2 which was probably due tothe excess negative charge in these soils Gonzales-Batista etal [10] reported that for systems free of permanent chargePZNC should coincide with pH
0 but for systems where
permanent and variable charges coexist PZNC may differfrom pH
0 Usually in the young soils (Entisols or Inceptisols)
PZNC is lower than its pH0and higher than pH
0if the soils
are highly weathered such as Oxisols [41] In addition themodel of Uehara and Gillman [11] and Yu [2] predict thatin soils having constant negative charge the PZNC value islower than pH
0and vice versa None of the charge variation
curves of the samples indicated the PZNC in pH betweenranges of 26 and 6 which was due to the excessive amountof negative charge compared with the positive charge inthese ranges of pH Besides the amount of estimated ZPNCin all the samples was lower than the pH
0 confirming the
presence of the permanent negative charge in these soils
6 Applied and Environmental Soil Science
Table3Ch
emicalprop
ertie
softhe
representativ
eprofiles
Soilnu
mber
Depth
(cm)
pHCa
Cl2
pHH2O
pHKC
lΔpH
(KClminusH
2O)
OC
SAR
CCE
EC dSmminus1
CEC
K+Na+
Mg2
+Ca2
+
Fed(
)(125)
cmol
ckgminus
1
1
0ndash25
765
779
760
minus019
034
742137
2985
414
067
2085
65
016
25ndash78
760
776
755
minus021
020
702498
275
263
022
1445
35
015
78ndash110
755
768
750
minus018
023
66
1983
325
334
036
1672
43
014
100ndash
150
770
787
762
minus025
012
772370
1811
313
017
154
52
33
015
2
0ndash20
785
797
780
minus017
018
36
2704
096
215
023
68
48
25
009
20ndash50
790
803
786
minus017
014
37
2755
040
182
022
57
46
22
010
50ndash100
780
795
773
minus022
013
182832
120
154
020
34
43
24
009
100ndash
150
790
794
774
minus020
016
07
2446
093
117
017
1417
23
010
30ndash
3077
579
077
0minus020
037
35
515
428
233
040
7767
28
011
30ndash80
779
793
774
minus019
020
46
5716
700
347
025
121
1032
013
80ndash150
783
797
778
minus021
017
45
5897
548
295
022
108
837
009
4
0ndash20
785
794
780
minus014
033
24
2884
264
176
051
52
47
53
010
20ndash70
793
802
792
minus010
035
30
2885
145
161
018
52
1346
012
70ndash9
578
079
277
5minus017
030
102729
103
144
018
184
1548
011
95ndash150
794
801
790
minus011
043
162798
121
117
015
26
08
43
015
50ndash
4577
578
8772
minus016
035
155820
154
151
021
28
06
65
012
45ndash150
790
804
785
minus019
038
03
5645
037
132
020
04
05
64
013
60ndash
4277
879
771
minus019
029
39
2824
516
275
039
9766
65
009
42ndash88
790
808
786
minus022
033
26
2353
210
195
017
57
48
50
011
88ndash150
789
806
787
minus019
016
48
2536
492
258
023
108
58
45
012
70ndash
3676
878
175
7minus024
037
29
6145
455
243
022
69
51
67
010
36ndash86
780
795
772
minus023
039
21
6041
525
267
024
54
61
64
009
86ndash150
784
798
780
minus018
029
29
6067
496
258
026
7589
45
010
80ndash
3078
079
1776
minus015
024
22
3112
057
168
036
426
43
009
30ndash70
785
789
783
minus006
025
21
3190
080
184
024
38
22
48
006
70ndash150
781
785
778
minus007
026
33
285
066
175
018
627
43
007
OC
organicc
arbo
nSA
Rsodium
adsorptio
nratio
CEC
cationexchange
capacityFe ddith
ionitecitrateb
icarbo
nateC
CEcalcium
carbon
atee
quivalentEC
electric
alcond
uctiv
ity
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
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MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
6 Applied and Environmental Soil Science
Table3Ch
emicalprop
ertie
softhe
representativ
eprofiles
Soilnu
mber
Depth
(cm)
pHCa
Cl2
pHH2O
pHKC
lΔpH
(KClminusH
2O)
OC
SAR
CCE
EC dSmminus1
CEC
K+Na+
Mg2
+Ca2
+
Fed(
)(125)
cmol
ckgminus
1
1
0ndash25
765
779
760
minus019
034
742137
2985
414
067
2085
65
016
25ndash78
760
776
755
minus021
020
702498
275
263
022
1445
35
015
78ndash110
755
768
750
minus018
023
66
1983
325
334
036
1672
43
014
100ndash
150
770
787
762
minus025
012
772370
1811
313
017
154
52
33
015
2
0ndash20
785
797
780
minus017
018
36
2704
096
215
023
68
48
25
009
20ndash50
790
803
786
minus017
014
37
2755
040
182
022
57
46
22
010
50ndash100
780
795
773
minus022
013
182832
120
154
020
34
43
24
009
100ndash
150
790
794
774
minus020
016
07
2446
093
117
017
1417
23
010
30ndash
3077
579
077
0minus020
037
35
515
428
233
040
7767
28
011
30ndash80
779
793
774
minus019
020
46
5716
700
347
025
121
1032
013
80ndash150
783
797
778
minus021
017
45
5897
548
295
022
108
837
009
4
0ndash20
785
794
780
minus014
033
24
2884
264
176
051
52
47
53
010
20ndash70
793
802
792
minus010
035
30
2885
145
161
018
52
1346
012
70ndash9
578
079
277
5minus017
030
102729
103
144
018
184
1548
011
95ndash150
794
801
790
minus011
043
162798
121
117
015
26
08
43
015
50ndash
4577
578
8772
minus016
035
155820
154
151
021
28
06
65
012
45ndash150
790
804
785
minus019
038
03
5645
037
132
020
04
05
64
013
60ndash
4277
879
771
minus019
029
39
2824
516
275
039
9766
65
009
42ndash88
790
808
786
minus022
033
26
2353
210
195
017
57
48
50
011
88ndash150
789
806
787
minus019
016
48
2536
492
258
023
108
58
45
012
70ndash
3676
878
175
7minus024
037
29
6145
455
243
022
69
51
67
010
36ndash86
780
795
772
minus023
039
21
6041
525
267
024
54
61
64
009
86ndash150
784
798
780
minus018
029
29
6067
496
258
026
7589
45
010
80ndash
3078
079
1776
minus015
024
22
3112
057
168
036
426
43
009
30ndash70
785
789
783
minus006
025
21
3190
080
184
024
38
22
48
006
70ndash150
781
785
778
minus007
026
33
285
066
175
018
627
43
007
OC
organicc
arbo
nSA
Rsodium
adsorptio
nratio
CEC
cationexchange
capacityFe ddith
ionitecitrateb
icarbo
nateC
CEcalcium
carbon
atee
quivalentEC
electric
alcond
uctiv
ity
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
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MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
Applied and Environmental Soil Science 7
Table4Re
lativea
bund
ance
ofcla
ymineralandsomee
lectrochem
icalcharacteris
ticso
fthe
soils
studied
Soilnu
mber
Depth
(cm)
Chl
Sme
Pal
IllKa
oSep
Ill-Sme
pH0120575pH
(KClminusH
2O)120575pH
(pH0minusCaC
l 2)120590119901(cmol
ckgminus
1 )120590max(cmol
ckgminus
1 )
1
0ndash25
178
3816
13mdash
lt8
335
minus019
minus465
minus38
minus48
25ndash78
1513
3711
24mdash
mdash320
minus021
minus440
minus273
minus35
78ndash110
2218
357
18mdash
mdash330
minus018
minus425
minus357
minus43
100ndash
150
2022
315
22mdash
mdash320
minus025
minus450
minus292
minus389
2
0ndash20
1616
2518
25mdash
mdash31
5minus017
minus470
minus212
minus295
20ndash50
3722
2412
5mdash
mdash290
minus017
minus500
minus191
minus27
50ndash100
3125
188
8mdash
lt10
300
minus022
minus480
minus143
minus22
100ndash
150
3029
177
9mdash
lt8
280
minus020
minus510
minus154
minus227
30ndash
3010
1533
266
mdashlt10
300
minus020
minus475
minus221
minus32
30ndash80
2121
3020
8mdash
mdash315
minus019
minus469
minus297
minus41
80ndash150
1126
2915
7mdash
lt12
310
minus021
minus446
minus318
minus42
4
0ndash20
238
1635
85
lt5
295
minus014
minus490
minus181
minus34
20ndash70
2014
1424
1810
mdash287
minus010
minus506
minus112
minus255
70ndash9
536
1610
209
9mdash
320
minus017
minus460
minus132
minus22
95ndash150
2720
915
98
lt12
314
minus011
minus480
minus172
minus209
50ndash
4518
1514
337
mdashlt13
311
minus016
minus464
minus159
minus241
45ndash150
2524
2130
mdashmdash
mdash325
minus019
minus465
minus142
minus224
60ndash
4220
1523
307
5mdash
301
minus019
minus477
minus245
minus32
42ndash88
1921
1524
88
lt5
287
minus022
minus503
minus201
minus289
88ndash150
2525
1220
99
mdash290
minus019
minus499
minus243
minus325
70ndash
3628
1432
26mdash
mdashTr
315
minus024
minus438
minus253
minus35
36ndash86
2420
3020
6mdash
mdash310
minus023
minus470
minus234
minus32
86ndash150
1926
1817
911
Tr315
minus018
minus454
minus243
minus34
80ndash
3030
1827
25mdash
mdashmdash
317
minus015
minus463
minus173
minus24
30ndash70
3326
2318
mdashmdash
mdash310
minus006
minus475
minus192
minus255
70ndash150
3430
2016
mdashmdash
mdash298
minus007
minus483
minus184
minus238
ChlchloriteSm
esm
ectitePalpalygorskiteIllilliteK
aokaolin
iteSepsepioliteIll-Smeillite-smectite
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
8 Applied and Environmental Soil Science
These data also agree with their mineralogical information(Table 4)
353 Permanent Negative Charge (120590119901) The 120590
119901has a positive
significant correlation with Fed (119903 = 063lowastlowast 119875 lt 001)Earlier the effects of Fed on the surface charge propertieswere discussed Hamdan et al [42] showed that chargecharacteristics were significantly correlated with soil organicmatter free iron oxides and clay content Sesquioxides haveamphoteric properties that is their surface charge can beareither positive charge in an acid condition or negative chargein an alkaline condition [43]
The 120590119901has a positive significant correlation with clay
content (119903 = 054lowastlowast 119875 lt 001) The results agree well withthose of Sharami et al [6] At high pH OHminus ions interactwith the edge of the clay particles making them neutral ornegatively charged [44]
Themineralogical compositions in these soils weremixedand each clay mineral plays an important role in the totalpermanent charge Although all soils are a mixture of per-manent and variable-charge components whether one or theother dominants depends largely on its mineralogy [45] Forinstance palygorskite has a positive significant correlationwith 120590
119901(119903 = 060lowastlowast 119875 lt 001) Structurally palygorskite
includes alternation of blocks and tunnels that grow alongthe length of the fiber Each structural block is composed oftwo discontinuous tetrahedral sheets of silica that a centraloctahedral sheet sandwiched between them Because of thediscontinuity of the silica sheets silanol groups (Si-OH) arepresent on the surface of the fiber
The 120590119901has a positive significant correlation with OC (119903 =
060lowastlowast 119875 lt 001) Organic matter also acts as an important
source of surface negative charge Oades et al [46] reportedseveral relationships between surface charge characteristicsand organic matter in an Oxisol under rainforest vegetationin Australia Hydroxyl groups of organic matter can alsocontribute to negative charge [2] Shamshuddin and Anda[47] showed that organic carbon in soils is responsible forlowering the pH
0because of the creation of negative surface
charge andor masking of positive surface chargeThe SAR exchangeable Na and exchangeable Mg also
have a positive significant correlation with 120590119901with 119903-values
of 084lowastlowast 092lowastlowast and 082lowastlowast respectivelyThrough alterationof the crystal lattice structure of soil colloids permanentcharge develops when ions of lower valence substitute forions of higher valence [48] The mechanisms of the effectof electrolyte on surface charge of soils are rather complexAccording to the theory of diffuse double layer two mech-anisms may exist The surface of variable charge minerals isone kind of reversible constant potential surface The chargedensity 120575 on this type of surface is proportional to the squareroot of ion concentration 119862 of the solution that is 120575 =119870(119862)12 where 119870 is a constant [28]
The valence ionic radius and thickness of hydrated layerof cations and anions of various electrolytes are differentMorais et al [49] showed that the nature and valence ofthe counterions also influenced the magnitude of the electriccharges on the soil particles For example the quantities of
negative surface charge and net surface charge in MgCl2
MgSO4 and K
2SO4solutions are lower than those in KCl
solutionFurthermore the 120590
119901has a positive significant correlation
with CEC (119903 = 096lowastlowast 119875 lt 001) This demonstrates that theCEC has the highest effect on the 120590
119901 Since organic matter is
low in the soils the CEC is affected by the expandingminerals(eg smectite) [50] and basic exchangeable cations (eg Na)Sollins et al [45] reported that most of the permanent chargein the soils is on the surfaces of layer-silicate clays whichcompose most of the surface area of p-c soils These claysinclude the 2 1 layer-silicates (illite vermiculite and smec-tite) and the 2 2 clays (chlorite)The 1 1 group of kaolin clayshas a small amount of permanent charge on their surface
The pHH2O has a positive significant correlation with the
permanent negative charge (120590119901) (119903 = 072lowastlowast 119875 lt 001)
The pHKCl also has a positive significant correlation with thepermanent negative charge (120590
119901) (119903 = 055lowastlowast 119875 lt 001)
Rashad and Dultz [51] indicated that at low pH the surfacecharge of both clay soil samples (original clay and the organicmatter removed clay soil) had low negative values whichis due to the protonation of variable charge with increasingpH where deprotonation of functional groups occurs thesurface charge becomes more negative Shamshuddin et al[52] reported that the negative charges on the soil surfacewere found to increase significantly with an increase in pHThus when the pH is raised more OHminus are adsorbed ontothe surface or H+ are released into the solution causing anincrease in negative charges
354 Charge Variation with pH Charge (negative andpositive) variations with pH (0002MCaCl
2) for different
horizons of the soils are presented in Figure 2 The inverserelations between both negative and positive charge variationcurves both in surface and between subsurface horizons(having small levels of variable charge components) werenoticeable The results showed that all of the samples showedlarge negative charge over the range of applied pH Thehighest level of negative charge was evident in profile 1 whichwas probably due to high levels of clay content in its surfaceand subsurface horizons and the relation to 2 1 claymineralsThe charge properties did not show any clear trend withdepth Since the plain is part of an alluvial and colluvial fanthe deposition of materials from the alluvial and colluvialwash varies from time to time creating different texturallayers For instance the level of negative charge in horizonCz1 (minus273 cmolckg
minus1) of profile 1 (Calcic Haplosalids) waslower than that of horizon Cyz2 (357 cmolckg
minus1) Hence thesoil electrochemical properties in profile 1 were different fromthe other studied pedons
Profile 4 (horizon C1) has the lowest negative charge (112
cmolckgminus1) which is probably due to low levels of clay content
and the relatively low smectite in this layer Profile 4 alsoshows the lowest levels of negative charge in both surface andsubsurface horizons compared with the other profiles due toits lower CEC clay content and smectite
The negative charge of the soils in the present study isinfluenced by the 2 1 clay minerals where they are prevalent
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
Applied and Environmental Soil Science 9
AEC (adsorbed Cl)CEC (adsorbed Ca)
AEC (adsorbed Cl)CEC (adsorbed Ca)
0
10
61453746538231245
Profile 2 (horizon A)
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 4 (horizon Ap)
05
623532423345289212
Surfa
ce ch
arge
(cm
olck
gminus1)
minus10
minus5
minus20
minus15
minus25
minus30
minus35
63657249413425
Profile 3 (horizon Ap)
0
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 1 (horizon Az)
6154433732270
10
minus10
minus20
minus30
minus40
minus50
minus60
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 5 (horizon A)
6534541362605
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 8 (horizon A)
5654633226723205
minus10
minus5
minus20
minus15
minus25
minus30
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 6 (horizon Ap)
544764135292420
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Profile 7 (horizon A)
653453829260
10
minus10
minus20
minus30
minus40
Surfa
ce ch
arge
(cm
olck
gminus1)
Figure 2 Charge variation with soil pH (0002MCaCl2) for different horizons
and organic matter accompanied by iron oxide is scarce(Tables 3 and 4) Consequently pH variations could nothave a great influence on the charge curve Therefore forsoil pH (CaCl
2) of 755 the amount of negative charge in
the subsurface horizon of profile 1 is more than the abovehorizon Naidu et al [53] studied the clay mineralogy andsurface charge characteristics of four basaltic soils fromWestern Samoa The level of trace to subordinate amounts ofkaolinminerals was present in these soilsThe surface charge-pH curves followed a constant potential model indicatingthe presence of substantial amounts of pH-dependent charge
In addition they reported that negative charge was presentat pH values as low as 30 and small quantities of positivecharge were detected at pH values as high as 90 Values forPZC ranged from 22 to 39 and these were generally greaterthan the pH
0determined by 120575pH method in their study The
permanent negative charge of the soils is high because themajority of parent materials are limestoneThe results agreedwell with those obtained by Sharami et al [6]
Generally for all the soils examined the ranges ofcharge variation with pH in the surface horizons were morenoticeable than in the subsurface horizons Most of these
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
10 Applied and Environmental Soil Science
variations were observed in the pH ranging from 35 to 50where the curves had a descending trend
The values of anion exchange capacity (AEC) in mostof the studied soils showed small levels which were dueto a shortage of materials having variable charge Howeverorganic matter and kaolinite are present in these soils butthese materials do not enhance the AEC level with respect totheir intrinsic characteristics and soil pH Another reason forthis observation (small level of AEC)was negative adsorption(repulsion) of anions from surfaces with variable chargeAdsorption of anions is one of the important characteristicsof variable-charge soils Owing to the properties of variable-charge soils in chemical and mineralogical compositionsadsorption of anions by these soils would have been moresignificant compared with adsorption by constant-chargesoils [54] Soils having variable charge occupying large areasin tropical and subtropical regions are characterized bycarrying variable amounts of both negative and positivecharges and therefore can adsorb both cations and anions[55] Hence the soils of the present study due to a shortageof materials having variable charge which is a commonproperty of soils from humid regions had small capacitylevels for anion adsorption
4 Conclusion
The soils of the studied area are young dominantly ofAridisols and Entisols Their mineralogy is dominated by the2 1 silicate layer clay minerals Consequently the pH
0and
the PZNC values in the arid soils are low in comparison withtropical soils The pH
0values of all samples are less than pH
under the field condition because of the high pH and thepresence of high amount of 2 1 silicate clay minerals Chargevariation curves in the soils did not give PZNC values withinpH range of 26 to 6 The PZNC values are less than pH
0in
all samples However permanent negative charge (120590119901) is high
in the arid soils because of presence of clay minerals (2 1 and1 1 types) Hence the 120590
119901has a significant positive correlation
with pH CEC OC SAR Na Mg clay and palygorskite Thecharge variation curves showed that the AEC values are smallwith values of lt283 cmolckg
minus1After this study we can recommend the application of
fertilizers based on the amount of negative charges in the soilsstudied
Acknowledgments
The authors are thankful to Universiti Putra Malaysia fortechnical and financial support They also thank membersof the Department of Land Management for providinglaboratory facilities to carry out this study
References
[1] X N Zhang and A Z Zhao ldquoSurface chargerdquo in Chemistry ofVariable Charge Soils T R Yu Ed pp 17ndash63 OxfordUniversityPress New York NY USA 1997
[2] T R Yu Chemistry of Variable Charge Soils Oxford UniversityPress New York NY USA 1997
[3] J Chorover M K Amistadi and O A Chadwick ldquoSurfacecharge evolution of mineral-organic complexes during pedo-genesis in Hawaiian basaltrdquo Geochimica et Cosmochimica Actavol 68 no 23 pp 4859ndash4876 2004
[4] MBarale CMansour F Carrette et al ldquoCharacterization of thesurface charge of oxide particles of PWR primary water circuitsfrom 5 to 320∘Crdquo Journal of NuclearMaterials vol 381 no 3 pp302ndash308 2008
[5] G Uehara and G P Gillman The Mineralogy Chemistry andPhysics of Tropical Soils with Variable Charge Clays West ViewPress Boulder Colo USA 1981
[6] S M Sharami A Forghani A Akbarzadeh and H Ramezan-pour ldquoMineralogical characteristics and related surface chargefluctuations of some selected soils of temperate regions ofnorthern Iranrdquo Clay Minerals vol 45 no 3 pp 327ndash348 2010
[7] M Anda J Shamshuddin C I Fauziah and S R S OmarldquoMineralogy and factors controlling charge development ofthree Oxisols developed from different parent materialsrdquo Geo-derma vol 143 no 1-2 pp 153ndash167 2008
[8] T Hou R Xu D Tiwari and A Zhao ldquoInteraction betweenelectrical double layers of soil colloids and FeAl oxides insuspensionsrdquo Journal of Colloid and Interface Science vol 310no 2 pp 670ndash674 2007
[9] C Taubaso M Dos Santos Afonso and R M Torres SanchezldquoModelling soil surface charge density using mineral composi-tionrdquo Geoderma vol 121 no 1-2 pp 123ndash133 2004
[10] A Gonzales-Batista J M Hernandez-Moreno E Fernandez-Caldas and A J Herbillon ldquoInfluence of silica content on thesurface charge characteristics of allophanic claysrdquo Clays amp ClayMinerals vol 30 no 2 pp 103ndash110 1982
[11] G Uehara and G P Gillman ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashI Theoryrdquo SoilScience Society of America Journal vol 44 pp 404ndash409 1980
[12] N C Brady and R R Weil The Nature and Properties of SoilsPrentice Hall Upper Sadller River NJ USA 13th edition 2002
[13] G Bellini M E Sumner D E Radcliffe and N P QafokuldquoAnion transport through columns of highly weathered acidsoil adsorption and retardationrdquo Soil Science Society of AmericaJournal vol 60 no 1 pp 132ndash137 1996
[14] D J Burdon ldquoHydrogeological conditions in the Middle EastrdquoQuarterly Journal of Engineering Geology vol 15 no 2 pp 71ndash82 1982
[15] M H Banaei ldquoSoil moisture and temperature region map ofIranrdquo Soil and Water Research Institute Ministry of Agricul-ture Tehran Iran 1998
[16] A H Moghimi ldquoSemi-detailed soil survey and classification inAshkara plain Iranrdquo Soil andWater research institute Ministryof Agriculture Tehran Iran 2002
[17] Soil Survey Staff ldquoSoil survey laboratory methods manualrdquo Soilsurvey investigation report No 42 version 4 Washington DCUSA 2004
[18] Soil Survey Staff ldquoKeys to Soil Taxonomyrdquo US Department ofAgriculture NRCS 2010
[19] G W Gee and J W Bauder ldquoParticle size analysisrdquo inMethodsof Soil Analysis A Klute Ed vol 9 of Agronomy Monograph 9ASA and SSSA Madison Wis USA 2nd edition 1986
[20] A Walkley and C A Black ldquoA critical examination of rapidmethod for determining organic carbon in soils effect of varia-tions in digestion conditions and of inorganic soil constituentsrdquoSoil Science vol 63 pp 251ndash263 1947
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
Applied and Environmental Soil Science 11
[21] O P Mehra and M L Jackson ldquoIron oxide removal from soilsand clays by a dithionitecitrate system buffered with sodiumbicarbonaterdquo Clay Minerals vol 7 pp 317ndash327 1980
[22] M K Conyers and B G Davey ldquoObservations on some routinemethods for soil pH determinationrdquo Soil Science vol 145 no 1pp 29ndash36 1988
[23] L P Van Reeuwijk ldquoProcedures for soil analysisrdquo in Proceed-ings of the International Soil Conference Information CentreNetherlands 2002
[24] G R Blake and K H Hartge ldquoBulk densityrdquo inMethods of SoilAnalysismdashPart 1 Physical and Mineralogical Methods A KluteEd Agronomy Monograph 9 ASA and SSSA Madison WisUSA 2nd edition 1986
[25] Salinity Laboratory Staff Diagnosis and Improvement of Salineand Alkali Soils USDA Handbook No 60 Washington DCUSA 1954
[26] L E Allison and C D Moodi ldquoCarbonaterdquo in Methods of SoilAnalysis C A Black Ed vol 9 of Agronomy pp 1379ndash13961965
[27] G P Gillman and M E Sumner ldquoSurface charge character-ization and soil solution composition of four soils from theSouthern Piedmont in Georgiardquo Soil Science Society of AmericaJournal vol 51 no 3 pp 589ndash594 1987
[28] H Van Olphen An Introduction to Clay Colloid ChemistryInterscience New York NY USA 2nd edition 1977
[29] G P Gillman and G Uehara ldquoCharge characteristics of soilswith variable and permanent charge mineralsmdashII Experimen-talrdquo Soil Science Society of America Journal vol 44 pp 252ndash2551980
[30] J A Kittrick and E W Hope ldquoA procedure for the particle sizeseparation of soils for X-ray diffraction analysisrdquo Soil Sciencevol 96 pp 312ndash325 1963
[31] M L Jackson Soil Chemical Analysis AdvancedCourse Univer-sity of Wisconsin College of Agriculture Department of soilsMadison Wis USA 1975
[32] A D Karathanasis and B F Hajek ldquoRevised methods for rapidquantitative determination ofminerals in soil claysrdquo Soil ScienceSociety of America Journal vol 46 no 2 pp 419ndash425 1982
[33] F Khormali and A Abtahi ldquoOrigin and distribution of clayminerals in calcareous arid and semi-arid soils of Fars Provincesouthern Iranrdquo Clay Minerals vol 38 no 4 pp 511ndash528 2003
[34] S A Khresat and E A Qudah ldquoFormation and properties ofaridic soils of Azraq Basin in northeastern Jordanrdquo Journal ofArid Environments vol 64 no 1 pp 116ndash136 2006
[35] I Navai ldquoExplanatory Text of the Hajiabad Quadrangle map1250000rdquo Geological Survey of Iran 1976
[36] H R Owliaie A Abtahi and R J Heck ldquoPedogenesis andclay mineralogical investigation of soils formed on gypsiferousand calcareous materials on a transect southwestern IranrdquoGeoderma vol 134 no 1-2 pp 62ndash81 2006
[37] M Emadi M Baghernejad H Memarian M Saffari and HFathi ldquoGenesis and clay mineralogical investigation of highlycalcareous soils in semi-arid regions of Southern Iranrdquo Journalof Applied Sciences vol 8 no 2 pp 288ndash294 2008
[38] H Khademi and J M Arocena ldquoKaolinite formation frompalygorskite and sepiolite in rhizosphere soilsrdquo Clays and ClayMinerals vol 56 no 4 pp 429ndash436 2008
[39] CA Coles andRN Yong ldquoHumic acid preparation propertiesand interactions with metals lead and cadmiumrdquo EngineeringGeology vol 85 no 1-2 pp 26ndash32 2006
[40] S-Z Li and R-K Xu ldquoElectrical double layersrsquo interactionbetween oppositely charged particles as related to surface chargedensity and ionic strengthrdquoColloids and Surfaces A vol 326 no3 pp 157ndash161 2008
[41] E Tessens and J Shamshuddin Quantitative RelationshipsbetweenMineralogy and Properties of Tropical Soils UPMPressSerdang Malaysia 1983
[42] J Hamdan B Ruhana and C P Burnham ldquoSurface chargedistribution of Three deep regoliths from Peninsular MalaysiardquoJournal of Sustainable Agriculture vol 18 no 1 pp 5ndash22 2001
[43] N P Qafoku E Van Ranst A Noble and A Baert ldquoVariablecharge soils their mineralogy chemistry and managementrdquoAdvances in Agronomy vol 84 pp 159ndash215 2004
[44] G SpositoTheChemistry of Soils OxfordUniversity Press NewYork NY USA 1989
[45] P Sollins G P Robertson and G Uehara ldquoNutrient mobility invariable- and permanent-charge soilsrdquo Biogeochemistry vol 6no 3 pp 181ndash199 1988
[46] J M Oades G P Gillman and G Uehara ldquoInteractions of soilorganic and variable-charge claysrdquo in Dynamics of Soil OrganicMatter in Tropical Ecosystems D C Coleman J M Oadesand G Uehara Eds pp 69ndash95 University of Hawaii PressHonolulu Hawaii USA 1989
[47] J Shamshuddin and M Anda ldquoCharge properties of soilsin Malaysia dominated by kaolinite gibbsite goethite andhematiterdquo Bulletin of the Geological Society of Malaysia vol 54pp 27ndash31 2008
[48] J B Yavitt and S J Wright ldquoCharge characteristics of soil ina lowland tropical moist forest in Panama in response to dry-season irrigationrdquo Australian Journal of Soil Research vol 40no 2 pp 269ndash281 2002
[49] F I Morais A L Paga and L J Lund ldquoThe effect of pHsalt concentration and nature of electrolytes on the chargecharacteristics of Brazilian tropical soilsrdquo Soil Science Society ofAmerica Journal vol 40 pp 521ndash527 1976
[50] C A Igwe F O R Akamigbo and J S C Mbagwu ldquoChemicaland mineralogical properties of soils in southeastern Nigeria inrelation to aggregate stabilityrdquo Geoderma vol 92 no 1-2 pp111ndash123 1999
[51] M Rashad and S Dultz ldquoDecisive factors of clay dispersionin alluvial soils of the Nile River Deltamdasha study on surfacecharge propertiesrdquoAmerican-Eurasian Journal of Agricultural ampEnvironmental Sciences vol 2 pp 213ndash219 2007
[52] J Shamshuddin S Paramananthan and N Mokhtar ldquoMineral-ogy and surface charge properties of two acid sulfate soils fromPeninsular Malaysiardquo Pertanika vol 9 pp 167ndash176 1986
[53] R Naidu R J Morrison L Janik and M Asghar ldquoClaymineralogy and surface charge characteristics of basaltic soilsfromWestern SamoardquoClayMinerals vol 32 no 4 pp 545ndash5561997
[54] J Li R Xu S Xiao and G Ji ldquoEffect of low-molecular-weightorganic anions on exchangeable aluminum capacity of variablecharge soilsrdquo Journal of Colloid and Interface Science vol 284no 2 pp 393ndash399 2005
[55] R Xu A Zhao and G Ji ldquoEffect of low-molecular-weightorganic anions on surface charge of variable charge soilsrdquoJournal of Colloid and Interface Science vol 264 no 2 pp 322ndash326 2003
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of
Submit your manuscripts athttpwwwhindawicom
Forestry ResearchInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental and Public Health
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EcosystemsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MeteorologyAdvances in
EcologyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Marine BiologyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom
Applied ampEnvironmentalSoil Science
Volume 2014
Advances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Environmental Chemistry
Atmospheric SciencesInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Waste ManagementJournal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal of
Geophysics
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Geological ResearchJournal of
EarthquakesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BiodiversityInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OceanographyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
ClimatologyJournal of