Association between Soil Fertility and Growth...

Research ArticleAssociation between Soil Fertility and Growth Performance ofPlanted Shorea macrophylla (de Vriese) after EnrichmentPlanting at Rehabilitation Sites of Sampadi Forest ReserveSarawak Malaysia

Mugunthan Perumal1 Mohd Effendi Wasli1 Ho Soo Ying1

Jonathan Lat2 and Hamsawi Sani1

1Department of Plant Science and Environmental Ecology Faculty of Resource Science and Technology Universiti Malaysia Sarawak94300 Kota Samarahan Sarawak Malaysia2Forest Department of Sarawak Wisma Sumber Alam Petra Jaya 93660 Kuching Sarawak Malaysia

Correspondence should be addressed to Mugunthan Perumal mugunthanperumal89gmailcom

Received 6 July 2017 Revised 20 September 2017 Accepted 31 October 2017 Published 28 November 2017

Academic Editor Kurt Johnsen

Copyright copy 2017 Mugunthan Perumal et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

A study was conducted to determine the status of soil properties after enrichment planting in comparison to an adjacent secondaryforest and to evaluate the effect of enrichment planting of Shorea macrophylla (de Vriese) on the soil fertility status with specialreference to Soil Fertility Index (SFI) and Soil Evaluation Factor (SEF) at Sampadi Forest Reserve Sarawak The study sites werestands rehabilitated in different years (1996 SM96 1997 SM97 1998 SM98 1999 SM99) and secondary forest (SF) Findingsindicated that the soils at rehabilitation sites and SF were strongly acidic in nature with pH less than 550 poor soil exchangeablebases and nutrient status The soils were relatively of sandy clay loam to sandy clay Principal Component Analysis revealed thethree most significant components of the soil properties which explained 763 of the total variation At surface soils SFI wascorrelated with tree growth parameters of S macrophylla indicating that SFI is an applicable soil quality index as compared to SEFNotwithstanding a significant association was found between soil available phosphorus and planted S macrophylla indicating thatsoil phosphorus is a better indicator than SFI Further studies on other environmental factors influencing tree growth performanceearly establishment of experimental reforestation at nursery and field should be implemented to obtain the initial data on seedlinggrowth performance prior to outplanting

1 Introduction

Many countries throughout the world are facing acutescarcity of lands for food production due to the rapid increaseof population and limited land resources which causespeople to convert forestland into agricultural horticulturalplantations and pastoral land for cattle settlements ormining[1] Such human activities have led to the depletion of existingforests throughout the world particularly in Asian countriesIn the tropics approximately 60 or 850 million hectaresof the total forest area between the year 1950 and 2000have been degraded and are difficult to regenerate due to

chemical biological and physical barriers [2] Consequentlythis has led to the attention of developing restoration orrehabilitation practices on degraded secondary forest [3ndash7] asto preclude further degradation [8 9] by means of improvingthe site productivity and quality [10 11] According to Doiand Sakurai [12] measuring soil quality using soil indices isessential to estimate the soil productivity or to rehabilitatedegraded lands Enrichment planting system has been usedas one of the promising techniques to recover and restore thedegraded forestland in the tropics [3 13 14]

Restoration of degraded forestland is indispensable toreduce soil nutrient loss and improve vegetation composition

HindawiInternational Journal of Forestry ResearchVolume 2017 Article ID 6721354 16 pageshttpsdoiorg10115520176721354

2 International Journal of Forestry Research

or stand for the purpose of environmental conservation[15] Rehabilitation efforts in degraded forestland due toabandoned shifting cultivation have been successfully imple-mented under the ecosystem rehabilitation [16] and byenrichment planting technique [17 18] in Sarawak MalaysiaIn Sarawak one of the common indigenous tree species fromDipterocarpaceae family Shoreamacrophylla (de Vriese) wasconsidered and selected for forest rehabilitation purposes[18 19] This climax species was chosen since it is one ofthe fastest growing species of the genus Shorea and is foundfrequently along rivers and in areas which are periodicallyinundated Likewise in Peninsular Malaysia rehabilitationof forestland that is degraded due to excessive harvestinghas been reforested through the technique of enrichmentplanting [20ndash23]

Knowledge of soil science for the better understanding ofthe effective soil management and conservation is requiredfor the rehabilitation of tropical rainforest on the land that isseverely degraded Consequently a multivariate strategy canbe implemented to measure the soil quality Since propertiesof the same soil may respond differently to a degradingimpact [24] it is expected to be more informative to quantifyand integrate various soil variables than measuring a singlevariable [12] A multivariate soil data set is regarded asintegrated properties of the soil According to Sena et al [25]integrating multiple soil physicochemical properties with theuse of a multivariate statistical technique often provides newmeasures that explain variations among the soils

Principal Component Analysis (PCA) is one of the pro-posedmultivariate statistical techniques used tomeasure andexplain the differences among soils In PCA a multivariatedata set is analyzed to reduce the original complicateddimensionality and to give a few principal components (PCs)that explain the variation in the data [12 21] Thus dataredundancy is avoided and the most significant PCs whichexplain the difference are specified Previous studies haveemphasized using PCA to identify PCs and important soilphysicochemical properties relating to the incidence of plantdisease [26] soil formation reflecting landscape [27] andother types of gradient

However for the case of Sarawak Malaysia intensiveresearch has to be done on the elucidation of soil prop-erties based on PCA and soil indices after enrichmentplanting in relation to the productivity of the potentialdipterocarp species in rehabilitating degraded forestlandMoreover attention has to be paid to the status of soilphysicochemical properties after rehabilitation since most ofthe previous researches have underlined the growth perfor-mance of planted species along with the different techniqueof planting [19 28] In addition information on the soil-plant relationship of indigenous species and soil fertilitystatus which might influence the survivorship and growthperformance of planted species under rehabilitation evenafter 14 years of the research is necessary for future forestmanagement programmes On the other hand Hamzah etal [23] stated that more comprehensive research has to beconducted on site productivity which could be improved byclarifying the potential of dipterocarp species in rehabilitatingdegraded forestland

Therefore in order to improve strategies and effectivetechnique for future rehabilitation efforts an evaluation studyof the rehabilitation programme in relation to growth per-formance of planted species and soil fertility status by usingPCA and soil indices could deliver significant information onspecies site preference [21]Themain emphasis was placed onfinding the significant soil properties based on PCA and theapplicability of the proposed indices the Soil Fertility Index(SFI) [29] and the Soil Evaluation Factor (SEF) [30] as analternative approach of indicator for estimating soil fertilityand site quality in the plantation for rehabilitation purposesin relation to the survivorship and growth performanceof the planted species Lu et al [30] mentioned that fora homogeneous forest with similar vegetation ages soilindices are often used to evaluate the soil conditions andthe dominant tree height is usually used to model the siteindices

Hence the aim of this studywas to determine the status ofsoil physicochemical properties under enrichment plantingin comparison to an adjacent secondary forest at SampadiForest Reserve Lundu Sarawak Malaysia In addition thepresent study also intended to evaluate the effect of enrich-ment planting of Shorea macrophylla (de Vriese) on the soilfertility status with special reference to Soil Fertility Index(SFI) and Soil Evaluation Factor (SEF) These indices sug-gested the applicability to the estimation of soil fertility andto the prediction of the increase in biomass in Amazonianhumid tropical forests under secondary successionThe scoreon the PC as a measure of changes of soil physicochemicalproperties after enrichment planting correlates with the SFIandor the SEF was investigated

2 Materials and Methods

21 Background and Information on Sampadi Forest ReserveRehabilitation Sites and Secondary Forest The presentstudy was conducted in a forest under enrichmentplanting at Sampadi Forest Reserve Lundu Sarawak(N01∘3410158401310158401015840E109∘5310158401210158401015840) and adjacent secondary forest(N01∘30101584026210158401015840E109∘58101584056710158401015840) which is located about 72 kmsouthwest of Kuching City (Figure 1)The area covers approx-imately 5163 hectares with an average elevation of 87mabove sea level The topography at the rehabilitation sitesand secondary forest is of the low undulating type SampadiForest Reserve has a humid subtropical seasonal climateand wet forest biozone (no dry season) with all monthsreceiving on average more than 100mm of precipitation[6] In the early hours of the morning the average surfaceannual temperature in the area is 22∘C (72∘F) and duringmid-afternoon it rises to around 31∘C (88∘F) with littlemonthly variation [31 32] According to our previous studyat the area the morphological characteristics of the soilsresemble Bako soil series as a dominant unit in associationwith Saratok series and are categorized mainly under the soilgroup of Grey-White Podzolic Soil based on the Sarawaksoil classification system [19 31] The soils in the study areawere derived from a mixture of sandstone coarse-grainedhumult ultisols and sandy residual parent material [19 28]Based on the USDA-NRCS classification system this soil

International Journal of Forestry Research 3

Kalimantan Indonesia

Sampadi Forest Reserve Lundu

Sarawak

South China Sea

Brunei

Saba

h

Kuching

Sarawak

W E

N

S(m)

(km)30

Scale 1 2000000

Figure 1 Location of the study area Sampadi Forest Reserve Lundu Sarawak Perumal et al [18]

group corresponds to Typic Paleaquults of Soil Taxonomy[19 33 34]

Based on the general in situ observation the current standcharacteristics of the secondary forests and forest within theenrichment plantingwere almost similar According to ForestDepartment of Sarawak [35] the Sampadi Forest Reserveis comprised predominantly of Mixed Dipterocarp Forest(MDF) and followed by Kerangas forest that had been loggedover with some riparian forest found along the main riversor streams of Batang Kayan The existing Mixed DipterocarpForest (MDF) within the research area had been loggedsince the year 1970ndash1980s and most of the forests have losttheir form and structure The upper storey of the MDF wasrepresented by relic stands of large trees between 30 and 35mtall and the diameter between 60 and 90 cm The dominantemergents wereMeranti Lun and Selangan batu (Shorea sp)Keruing (Dipterocarpus sp) Menggris (Koompassia malac-censis) Tapang (Koompassia excelsa) Tampar hantu (Sindoraspp) and Geronggang (Cratoxylum arborescens) The mid-storey was dominated by sparse clusters of smaller treesattaining heights of 15ndash25m and diameter of 30ndash50 cm suchas Empenit (Lithocarpus sp) Kayu massam (Aporusa sp)Kayu malam (Diospyros sp) and Ubah (Eugenia sp) Thelower storey was occupied by dense thickets of small treesand regeneration of larger species The presence of skidtrail and the logging gaps creates dense colonization bywoody and nonwoody pioneer tree species Woody speciesare represented by Benua (Macaranga sp) Kelampayan(Anthocephalus chinensis) Kayu ara (Ficus sp) Sabar besi(Callicarpa sp) and Buan or Simpor (Dillenia suffruticosa)and nonwoody species are represented by Paku kelindang(Blechnum orientale) wild ginger (Alpinia sp Amomum spand Costus sp) and Daun long (Phrynium sp)

Pockets of Kerangas forest remained generally undis-turbed due to the presence of very poor podzolized soilsAmong the tree species typical of this forestwere Somah (Ploi-arium alternifolium) and Geronggang biabas (Cratoxylum

formosum) which were small in diameter and rarely attainthe height of eight metersThe riparian forest along themajorrivers or streams had lost their original forms and structurethrough shifting agriculture or past logging activities Thepreparation of sites prior to the plantation establishmentand planting technique used were mentioned and explainedin the previous study [18 28] The planted species in thestudy area were mainly from Dipterocarpaceae family suchas Engkabang jantong (Shorea macrophylla) Meranti sarangpunai (Shorea parvifolia) Selangan batu (Shorea falcifera)Kapur bukit (Dryobalanops beccarii) and Bintangor bukit(Calophyllum alboramulum)

22 Experimental Design and Methods for Soil SamplingIn order to clarify the soil properties in greater detail sixexperimental plots sized 25m times 25m in the rehabilitationsites were constructed for stands of six ages Abbreviationswere applied to represent the studied plots as follows plantedwith Shorea macrophylla in the year 1996 SM96 1997 SM971998 SM98 and 1999 SM99 Study plots sized 20m times 20mwere established for soil sampling at the adjacent secondaryforest (SF 30 years) outside the rehabilitation areas For thesoil sampling at the rehabilitated areas soil samples werecollected on the planting line at the depth of 0ndash10 cm (surfacesoils) and 30ndash40 cm (subsurface soils) at three randompointswithin each 25m times 25m plot in each age stands and weremixed well to get a composite sample for each soil layer[19 28 36] Similarly three random points within the 20mtimes 20m plots located outside the rehabilitated sites (SF) weredesignated for soil sampling and soils were collected at thedepth of 0ndash10 cm (surface soils) and 30ndash40 cm (subsurfacesoils) and mixed well to get a composite sample for each soillayer Undisturbed soil samples were collected at the depthof 0ndash10 cm and 30ndash40 cm using a 100-cc core sampler forthe determination of soil physical properties The generalinformation of each rehabilitation sites and adjacent sec-ondary forest is shown in Table 1The collected composite soil


Table 1 General information of the study sites SM96 SM97 SM98 SM99 (rehabilitation sites) and secondary forest (SF)

Study sites Year planted GPS location Species Planting techniqueSM96 1996 N01∘30101584015010158401015840 E109∘55101584000310158401015840 Shorea macrophylla Line plantingSM97 1997 N01∘30101584012010158401015840 E100∘54101584056010158401015840 Shorea macrophylla Line plantingSM98 1998 N01∘30101584012110158401015840 E109∘54101584054810158401015840 Shorea macrophylla Line plantingSM99 1999 N01∘30101584012110158401015840 E109∘52101584054310158401015840 Shorea macrophylla Line planting

SF Secondary forest N01∘30101584026210158401015840 E109∘58101584056710158401015840 Naturally grown secondaryvegetation pioneer species

samples were air-dried for a week crushed and homogenizedand all the plant materials such as fine roots leaves and twigswere carefully removed Later the air-dried soil samples werepassed through a 2mmmesh sieve before use for further soilphysicochemical analyses

23 Methods for Soil Physicochemical Analyses Soil pH(H2O) was determined in water and pH (KCl) in 1MKCl in a soil to solution ratio of 1 5 by glass electrodemethod Electrical conductivity (EC) of soil was measuredusing the supernatant solution after reciprocal shaking for1 hour at the soil to water ratio of 1 5 and examined usingconductivity meter (Eutech Instruments-Cyberscan Con 11)The filtrate from the pH (KCl) measurement was used forsoil exchangeable Al analysis Exchange acidity (Al + H)was determined using the titration method with 001MNaOH and the content of the exchangeable Al with 001MHCl [37] Total carbon (Total C) and organic matter (OM)contents in soil were determined using the loss on ignitionmethod [38 39] In addition the soil total nitrogen (Total N)content was determined by Kjeldahl acid digestion method[40] The contents of soil exchangeable bases (Ca Mg Kand Na) and soil cation exchange capacity (CEC) weremeasured after three times of successive extraction using1M ammonium acetate NH4-OAc adjusted to pH 70 and10 NaCl respectively in a soil to solution ratio of 1 5The contents of soil exchangeable bases were determinedby atomic absorption spectrophotometry (Thermo ScientificICE Series 3500) for Ca Mg K and Na Steam distillationand titration methods were used to determine the cationexchange capacity of the soil Available phosphorus (AvailableP) content in soil was quantified by the Bray II methodin a soil to extractant ratio of 1 20 [41 42] with UV-Vis Spectrophotometer at a wavelength of 710 nm (Jasco V-630) Soil particle size distribution was determined using thepipette method [43] Soil bulk density was determined onthe undisturbed samples collected at each soil horizon depthusing a 100-cc core sampler with the ratio of the dry mass ofsoil to the bulk volume of a soil core Soil particle density wasdetermined using graduated cylinder method [44] All soilphysicochemical analyses were conducted at the Laboratoryof Environmental Soil Science Faculty of Resource Scienceand Technology Universiti Malaysia Sarawak (UNIMAS)

24 Statistical Analyses All data of soil were expressed onan oven-dry basis In order to indicate the changes of soil

physicochemical properties among the rehabilitated sites inrelation to the age of Shorea macrophylla since planting dataon soil physicochemical properties at surface and subsurfacesoils were statistically analyzed and compared using linearregression at 5 and 1 levels respectively A mathematicalmodel Principal Component Analysis (PCA) was used toavoid the redundancy of multivariate data and to determinethe most prominent soil parameters which had an influenceon the fertility of the soils by integrating the soil physico-chemical properties Integrating PCA score with a soil indexwhich represents a soil fertility status is crucial for estimatingthe soil fertility and quality in humid tropical forests Inthis study two soil indices the Soil Fertility Index (SFI)[29] and Soil Evaluation Factor (SEF) [30] were used forestimating soil fertility and site quality Linear regressionanalysis between the scores on a principal component (PC)as an integrated measure of soil fertility SFI or SEF wasexamined to investigate if the indices can be measures of soilfertility in the rehabilitation sites of Sampadi Forest ReserveNonetheless in this study linear regression analysis betweenthe PC score SFI and SEF as well as tree growth parameters(diameter at breast height and total height) and survival basedon our previous study [19] is performed to clarify the soil-plant association in order to predict a good indicator forestimating soil fertility and site quality in relation to Shoreamacrophylla enrichment planting All statistical analyses wereperformed using SPSS version 180 for windows Lu et al [30]reported that the SFI was applied to measuring soil fertilityin an Amazonian humid tropical region On the other handsignificant correlationwas found byMoran et al [29] betweenthe SFI as a measure of quality of Amazonian Ultisols orOxisols and the succession rate of the secondary tropicalforest In our previous study [28 45] the following equationwas used to determine the SFI [29]

SFI = pH + organic matter ( dry soil basis)

+ available P (mgkgminus1 dry soil)

+ exchangeable K (cmolc kgminus1 dry soil)

+ exchangeable Ca (cmolc kgminus1 dry soil)

+ exchangeable Mg (cmolc kgminus1 dry soil)

minus exchangeable Al (cmolc kgminus1 dry soil)

(1)


However the SFImay largely depend on pH but an extremelyhigh pH inhibits plant growth In addition pH is not an inde-pendent but a dependent variable of the relative proportionof Ca Mg and exchangeable Al concentrations in the soil Alatent drawback of the SFI was pointed out by [30] since themeaning of SFI is not clear In order to improve this drawbackthey developed another index the Soil Evaluation Factor(SEF) for evaluating status of the Amazonian Ultisols andOxisols The SEF values were calculated using the followingequation in our previous study

SEF = [exchangeable Ca (cmolc kgminus1 dry soil)


+ exchangeable K (cmolc kgminus1 dry soil) minus log (1

+ exchangeable Al (cmolc kgminus1 dry soil))]

times organic matter ( dry soil basis) + 5

(2)

3 Results and Discussion

31 Soil Physicochemical Properties under Various Age Standsof Rehabilitation Sites and Secondary Forest at Sampadi ForestReserve Lundu Sarawak The mean average values of soilphysicochemical properties of rehabilitation sites (SM96SM97 SM98 and SM99) and adjacent secondary forest (SF)are presented in Tables 2(a) and 2(b) In general the soiltexture did not vary widely in all the study sites where mostsoils were relatively sandy ranging from sandy clay loam tosandy clay in texture The content of sand in surface andsubsurface soils was fewer than 56while that of clay contentwas above 29 The clay contents in surface and subsurfacesoils were 290 to 459 and 312 to 481 respectively Onthe other hand the sand content in surface and subsurfacesoils ranged from293 to 537 and 314 to 552 respectivelyComparatively soil organicmatter (SOM) in surface soils wasrelatively higher than that of the subsurface soilsThe averageSOM values at the surface and subsurface soils ranged from663 to 930 and 388 to 597 respectively The averageSOM for the secondary forest (SF) presented higher value incomparison to that of the rehabilitation sites (SM96 SM97SM98 and SM99)

Soils of all the study sites in Sampadi Forest Reserve couldbe characterized as strongly acidic with pH (H2O) values ofless than 550 (ranging from 467 to 529 and 501 to 538)at both surface and subsurface soil layers respectively Thesoil pH (KCl) of all study sites was moderately acidic at pHless than 450 (ranging from 363 to 431 and 372 to 448) atboth surface and subsurface soil layers respectively On theother hand the soil electrical conductivity at the surface andsubsurface soil ranged from 1200 to 1936120583S cmminus1 and 475 to1329 120583S cmminus1 respectively In terms of soil total carbon (TotalC) and total nitrogen (Total N) the soils in this study hadhigher values in surface soils than in subsurface soilsThe soilTotal C value for surface soil ranged from 385 to 539 g kgminus1and that for subsurface soil ranged from 226 to 346 g kgminus1At the depth of 0ndash10 cm the Total N level of soil ranged from

216 to 305 g kgminus1 whereas at the depth of 30ndash40 cm it rangedfrom 095 to 161 g kgminus1 Generally the contents of Total Cand Total N in secondary forest (SF) were higher than that ofthe rehabilitation sites Among the five study sites secondaryforest showed the highest level of Total C and Total N at bothsurface and subsurface soils which leads to the lower valueof CN ratio as compared to other study sites except in SM99In spite of high Total C and Total N contents in the secondaryforest (SF) no clear difference was detected for CN ratio inrehabilitation sites and secondary forest (SF)

In general the soil cation exchange capacity (CEC) valuewas low for the surface and subsurface soils for all therehabilitation sites and secondary forest The CEC valueranged from 84 to 118 cmolc kg

minus1 in surface soils and rangedfrom70 to 93 cmolc kg

minus1 in subsurface soils For surface soilsthe highest value was from SM96 (118 cmolc kg

minus1) while thelowest value was from SM99 (84 cmolc kg

minus1) On the otherhand as for the subsurface soils the highest CEC was fromthe secondary forest (SF) (93 cmolc kg

minus1) and the lowest wasfrom SM98 (70 cmolc kg

minus1)Throughout the sites soil exchangeable cations (Ca Mg

and K) in surface soils were found higher as compared tothe subsurface soils The soil exchangeable Ca at surfaceand subsurface soils ranged from 026 to 068 cmolc kg

minus1

and 002 to 043 cmolc kgminus1 respectively The exchangeable

Mg ranged from 024 to 038 cmolc kgminus1 at surface soils

and ranged from 011 to 015 cmolc kgminus1 at subsurface soils

The exchangeable K ranged from 012 to 032 cmolc kgminus1 at

surface soils and ranged from 006 to 025 cmolc kgminus1 at

subsurface soils In comparison to soil exchangeable Al theexchangeable bases in surface and subsurface soils were lowresulting in a high level of Al saturation at rehabilitationsites as well as secondary forest Al saturation was depictedabove 40 at surface soils and more than 60 at subsurfacesoils Comparatively the soil exchangeable Al in subsurfacesoils was greater than the surface soils for rehabilitationsites and secondary forest except for SM98 whereby thesoil exchangeable Al contents were greater in surface soilsas compared to the subsurface soils However in SM99the soil exchangeable Al content was the same for surfaceand subsurface soils At the depth of 0ndash10 cm the soilexchangeable Al ranged from 135 to 403 cmolc kg

minus1 andranged from 130 to 430 cmolc kg

minus1 at the depth of 30ndash40 cmThe values of soil available P in surface and subsur-

face soils ranged from 24 to 140mg P kgminus1 and 09 to59mg P kgminus1 respectively The average soil bulk density ofsubsurface soils was higher than that of surface soils Thesoil bulk density at the depth of 0minus10 cm ranged from 090to 108 gmLminus1 and at the depth of 30minus40 cm ranged from111 to 136 gmLminus1 Secondary forest (SF) had the lowest soilbulk density value (090 gmLminus1) as compared to that of therehabilitation sites and SM96had the highest soil bulk densityvalue (108 gmLminus1) at surface soils At subsurface soils SM97depicted the lowest value in soil bulk density (111 gmLminus1)and SM98 depicted the highest value in soil bulk density(136 gmLminus1)


Table 2 (a) Means and standard deviation of surface soil physicochemical properties at rehabilitation sites (SM96 SM97 SM98 and SM99)and secondary forest (SF) (b) Means and standard deviation of subsurface soil physicochemical properties at rehabilitation sites (SM96SM97 SM98 and SM99) and secondary forest (SF)

(a)

Age-since-plantingsoil physicochemicalproperties

Rehabilitation sites Secondary forestSM96

(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF

(30 years)Surface soil 0ndash10 cm depthpH (H2O)

lowastlowast 469 plusmn 012 467 plusmn 009 472 plusmn 008 520 plusmn 006 529 plusmn 026pH (KCl)lowastlowast 392 plusmn 008 363 plusmn 056 407 plusmn 005 431 plusmn 007 416 plusmn 015ECalowastlowast (120583S cmminus1) 1200 plusmn 133 1632 plusmn 329 1657 plusmn 510 1936 plusmn 106 1882 plusmn 252SOMb () 663 plusmn 171 854 plusmn 151 891 plusmn 206 852 plusmn 083 930 plusmn 140Total Cc (g kgminus1) 385 plusmn 99 496 plusmn 88 517 plusmn 120 494 plusmn 48 539 plusmn 81Total Nd (g kgminus1) 216 plusmn 067 255 plusmn 038 299 plusmn 101 291 plusmn 080 305 plusmn 050CN ratio 1827 plusmn 289 1954 plusmn 300 1822 plusmn 455 1774 plusmn 346 1778 plusmn 143CECelowast (cmolc kg

minus1) 118 plusmn 28 97 plusmn 16 95 plusmn 16 84 plusmn 30 102 plusmn 12Exch Ca2+ (cmolc kg

minus1) 052 plusmn 017 048 plusmn 025 068 plusmn 025 026 plusmn 028 054 plusmn 043Exch Mg2+ (cmolc kg

minus1) 033 plusmn 007 035 plusmn 017 024 plusmn 009 030 plusmn 004 038 plusmn 020Exch K+lowast (cmolc kg

minus1) 015 plusmn 004 012 plusmn 002 018 plusmn 003 017 plusmn 003 032 plusmn 003Exch Al3+lowastlowast (cmolc kg

minus1) 254 plusmn 082 403 plusmn 040 135 plusmn 019 156 plusmn 024 140 plusmn 041SUMflowastlowast (cmolc kg

minus1) 145 plusmn 023 135 plusmn 042 136 plusmn 035 084 plusmn 032 177 plusmn 062ECECglowastlowast (cmolc kg

minus1) 399 plusmn 101 538 plusmn 040 271 plusmn 051 240 plusmn 044 316 plusmn 065Base saturation () 126 plusmn 23 143 plusmn 48 141 plusmn 16 115 plusmn 64 172 plusmn 55Available Plowastlowast (mg P kgminus1) 140 plusmn 21 136 plusmn 15 63 plusmn 10 24 plusmn 11 55 plusmn 12Al saturation () 629 plusmn 51 750 plusmn 67 504 plusmn 44 658 plusmn 76 445 plusmn 136Claylowastlowast () 290 plusmn 88 369 plusmn 58 412 plusmn 72 403 plusmn 67 459 plusmn 19Siltlowastlowast () 218 plusmn 59 338 plusmn 42 51 plusmn 27 68 plusmn 33 64 plusmn 21Sand () 491 plusmn 119 293 plusmn 71 537 plusmn 74 530 plusmn 91 477 plusmn 26Bulk density (gmLminus1) 108 plusmn 007 092 plusmn 013 101 plusmn 009 093 plusmn 008 090 plusmn 004Particle density (gmLminus1) 252 plusmn 016 249 plusmn 015 232 plusmn 018 283 plusmn 065 242 plusmn 009Moisture content () 30 plusmn 09 44 plusmn 05 36 plusmn 05 40 plusmn 07 40 plusmn 02Values in the same row indicate means plusmn standard deviation aEC electrical conductivity bSOM soil organic matter cTotal C total carbon dTotal Ntotal nitrogen eCEC cation exchange capacity f sum of exchangeable bases (Ca Mg K and Na) gECEC effective CEC sum of exchangeable bases andexchangeable Al lowastlowastlowastCorrelations are significant at 5 and 1 levels respectively among the rehabilitation sites

(b)

Age-since-plantingSoil physicochemicalproperties


(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF

(30 years)Subsurface soil 30ndash40 cm depthpH (H2O)

lowastlowast 501 plusmn 005 504 plusmn 005 535 plusmn 016 529 plusmn 005 538 plusmn 005pH (KCl)lowastlowast 391 plusmn 006 372 plusmn 004 427 plusmn 005 433 plusmn 006 448 plusmn 005ECalowastlowast (120583S cmminus1) 527 plusmn 70 546 plusmn 29 475 plusmn 79 1223 plusmn 19 1329 plusmn 133SOMb () 388 plusmn 090 403 plusmn 074 444 plusmn 085 470 plusmn 084 597 plusmn 089Total Cc (g kgminus1) 226 plusmn 52 234 plusmn 43 258 plusmn 49 273 plusmn 49 346 plusmn 51Total Ndlowast (g kgminus1) 095 plusmn 044 106 plusmn 017 107 plusmn 029 134 plusmn 030 161 plusmn 041CN ratio 2625 plusmn 803 2210 plusmn 340 2470 plusmn 397 2062 plusmn 328 2200 plusmn 295CECe (cmolc kg



minus1) 012 plusmn 004 015 plusmn 010 011 plusmn 007 011 plusmn 001 014 plusmn 007Exch K+lowastlowast (cmolc kg


minus1) 272 plusmn 118 430 plusmn 066 130 plusmn 030 156 plusmn 017 181 plusmn 023


(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF

(30 years)SUMf (cmolc kg


minus1) 337 plusmn 133 506 plusmn 076 216 plusmn 044 188 plusmn 016 269 plusmn 038Base saturation () 86 plusmn 24 104 plusmn 15 126 plusmn 41 43 plusmn 09 95 plusmn 30Available Plowastlowast (mg P kgminus1) 59 plusmn 15 37 plusmn 04 26 plusmn 13 33 plusmn 19 09 plusmn 03Al saturation () 790 plusmn 76 850 plusmn 23 605 plusmn 94 829 plusmn 30 676 plusmn 89Clay () 312 plusmn 69 377 plusmn 64 361 plusmn 86 365 plusmn 58 481 plusmn 25Siltlowastlowast () 258 plusmn 58 309 plusmn 28 87 plusmn 75 87 plusmn 35 49 plusmn 11Sandlowastlowast () 430 plusmn 70 314 plusmn 87 552 plusmn 132 549 plusmn 38 470 plusmn 29Bulk density (gmLminus1) 132 plusmn 014 111 plusmn 004 136 plusmn 012 135 plusmn 018 113 plusmn 019Particle density (gmLminus1) 250 plusmn 015 253 plusmn 009 240 plusmn 014 268 plusmn 014 262 plusmn 027Moisture content () 26 plusmn 09 37 plusmn 07 28 plusmn 06 33 plusmn 07 37 plusmn 04

Values in the same row indicate means plusmn standard deviation aEC electrical conductivity bSOM soil organic matter cTotal C total carbon dTotal Ntotal nitrogen eCEC cation exchange capacity f sum of exchangeable bases (Ca Mg K and Na) gECEC effective CEC sum of exchangeable bases andexchangeable Al lowastlowastlowastCorrelations are significant at 5 and 1 levels respectively among the rehabilitation sites

32 Soil Texture Organic Matter and Cation ExchangeCapacity-Related Properties The fertility of tropical soils ismainly dependent on the negative charges derived from claycontent and organic matter under the acidic nature of thesoils [46ndash48] In the present study a high positive correlationwas observed between Total C and clay contents in boththe surface soils and subsurface soils 119903 = 0832lowastlowast and119903 = 0880lowastlowast (data not shown) respectively This indicatedthat they are ascribable to soil organic matter stabilizationby the stable organomineral complexes formation [48 49]However the results of standardized multiple regressionanalysis showed no correlation between CEC values andeither Total C or clay contents in either surface (CEC = 0211Total C minus 0057 clay (119903 = 0167)) or subsurface soils (CEC= 0504 Total C + 0199 clay (119903 = 0686)) The fact that theCEC was higher as compared to the effective cation exchangecapacity (ECEC) suggested the possible existence of certainvariable negative charges [47 50] Since the ECECvaluesweremuch lower than theCECvalues permanent negative chargesof clay minerals were predominant under acidic conditionsThe small difference between soil CEC and ECEC suggestedlow input of negative charges from soil organic matter to thecation retention capacity [21] Although the content of soiltotal carbon was significantly higher in secondary forest thanrehabilitation sites there was no large difference betweenthe rehabilitation sites and secondary forest for soil totalcarbon total nitrogen or clay contents It is notable thatthe negative charges derived from clay content and organicmatter are considered as a significant factor for nutrientretention capacity and possibly influence the fertility statusof soils to a certain extent [23] In addition the soil Total CTotal N and CEC values are also likely to be affected by theinput-output balance of soil organic matter after the periodof establishment of the rehabilitation sites and in the fallowperiod of the secondary forest through inputs of litterfall andoutput by decomposition

According to Akbar et al [51] organic matter from thesoil gradually decreased after harvesting or clearing of forestdue to the loss of organic matter source from the plantNevertheless similar studies by Nye and Greenland [52]Kendawang et al [16] and Ilstedt et al [7] mentioned thatthe soil organic matter decreases rapidly after the soil wasexposed to land clearing or harvesting activities A studyby Ishizuka et al [53] reported that the soil organic mattercontentwas high in the surface layers due to the accumulationof forest litter and the development of root mats in the soilSimilar findings revealed in the present studywhereby the soilorganicmatter values in surface soils were generally higher ascompared to the subsurface soils The higher content of soilTotal C especially in the secondary forest was likely due to alarge input and greater accumulation of fresh organic matterin soils from the existing vegetation in the former than thelatter

33 Soil Acidity and Exchangeable Bases-Related PropertiesAccording to Juo andManu [54] the loss of soil exchangeablebases via uptake by vegetation and leaching in the tropicalenvironment as well as volatilization during combustionhad caused soils being acidic in nature especially in thereforestation sites [55] In addition Tan [44] reported thatfor soil pH below 60 some available nutrients are poor Theformation of clay minerals and microbial activity includingsoil characteristics and processes are influenced by the soilpH In the present study especially in SM96 and SM97 reha-bilitation sites the soil pH for both surface and subsurfacesoils wasmore acidic as compared to the secondary forest dueto the occurrence of high soil exchangeable Al The presenceof a large amount of aluminium and hydrogen ions in thesoils resulted in the acidity of forest soils In addition Zaideyet al [15] stated that the soil organic matter content andAl concentrations probably contributed to the soil acidityAlthough aluminium is not useful for plant growth and notdeliberated as a plant nutrient it could be used as an indicator


for weathering status and acidity of the soils Akbar et al[51] mentioned that Al toxicity will disturb and restrict thegrowth of seedling and the acidity presumably caused bywater deficiency during drought season Accumulation offorest litter and development of root mats on the surfacelayer of soil may result in high carbon content which mayindirectly affect the acidity of the soil

Nonetheless Etsuko et al [56] reported that higheramount of calcium corresponds to the higher pH valueAssociation of biological accumulation through the supplyof forest litter and their lower mobility in soil caused highercontents of soil exchangeable Ca and Mg in surface soils[57 58] During heavy rainfall season the exchangeable Kfrom the decomposition of dead plants probably dissolvedeasily into the deep layer of soil In addition Ohta and Effendi[59] described that subsurface soil may play a vital role asa nutrient storage whereby some available nutrients in thesubsurface layer are pumped up and transferred gradually tothe surface soil

34 Identification of Intrinsic Soil Properties in relation toSoil Fertility at Rehabilitation Sites Principal ComponentAnalysis (PCA) is a multivariate data analysis used to analyzeset of soil physicochemical properties to reduce the originalcomplicated dimensionality and to give a few principalcomponents (PC score) that explain the variation in the data[21] In the present study PCA was computed and performedfor the rehabilitated sites (SM96 SM97 SM98 and SM99)by using thirteen selected variables related to the surfaceand subsurface soil physicochemical properties in order todetermine the important variables that affect the soil fertilityat the study sites as shown in Table 3

The PCA results generated three most significant PCscores (PC1 PC2 and PC3) which described approximately763 of the total variability and each component portrays aseries of variables which simplifies the analysis and interpre-tation The first component score (PC1) represents intrinsicproperties of the soil related to phosphorus soil acidity andsoil texture such as exchangeable Al available phosphorusand silt content which exhibited high positive factor loadingswhile pH (H2O) and sand content exhibited high negativefactor loadings for surface soils The second principal com-ponent (PC2) showed a high positive factor loading for totalnitrogen clay content and soil organicmatter whereas a highnegative factor loading for bulk density reflects soil organicmatter constituent at surface soils Meanwhile at subsurfacesoils the first principal component (PC1) was related to soilacidity and soil texture as exchangeable Al and silt contentshowed high positive factor loadings while pH (H2O)sand content and bulk density showed high negative factorloadings (Table 3) On the other hand PC2 for subsurfacesoils showed a high positive factor loading for total nitrogenexchangeable K clay content and bulk density reflecting thecation retention capacity and soil organic matter constituentThe third principal component (PC3) at subsurface soilswas related to available nutrient as exchangeable Ca showeda high negative factor loading Thus based on the resultsobtained this indicated that the PCA produces the abilityof the three principal component scores to integrate soil

physicochemical characteristics within the components Inaddition the information derived from PCA can be appliedto the development of basic indicators which can be used toexplain the more complex variability of soil physicochemicalproperties Based on PCA since subsurface soil propertiesshowed similar but fewer tendencies than those of the surfacesoils the intrinsic results of surface soils properties will bechiefly used for further discussionThefirst component scorePC1 from PCA will be used for the discussion since it showsthe highest contribution ratio (344) as compared to PC2(292) and PC3 (127)

35 Relationship between Soil Fertility and Growth Perfor-mance of Planted Shorea macrophylla (de Vriese) at Different-Age Stands with Special Reference to PC Score SFI and SEFThe suitable procedure to assess the soil conditions in thetropical rainforests was found difficult due to the variations ofsoil properties In forest management the evaluation of soilfertility status and site quality is essential since it reflects theproductive capacity of the forest area to support the growthof plants [21 30] Moran et al [29] stated that a Soil FertilityIndex (SFI) was employed to investigate the relationshipbetween soil fertility and secondary forests succession rateas well as vegetation selection while the Soil EvaluationFactor (SEF) was used to evaluate soil fertility with differentsoil types [30] Originally the Soil Fertility Index (SFI)was developed as a measure of fertility of soils for cacaoproduction [60] In the Amazonian humid tropical forestsof Brazil both of these soil indices were used to predictthe increase in aboveground biomass and to evaluate soilfertility and site productivity under various stages of tropi-cal secondary forests succession Furthermore in NorthernThailand studies have proven that SFI and SEF have beenused for soil quality and productivity along a gradient ofland degradation [12] However less attention has been paidto the applicability of using these soil indices for estimatingsoil fertility and site quality in secondary forests undergoingrehabilitation especially by using indigenous species [21](Dipterocarp species such as Shorea macrophylla) as for thecase in this study To investigate if any proposed index forestimating soil quality is applicable to the soils in SampadiForest Reserve as well as for the association between the soilfertility status and productivity of planted Shoreamacrophylla(de Vriese) after enrichment planting correlations betweenthe PCA score and the values of Soil Fertility Index (SFI) [29]and Soil Evaluation Factor (SEF) [30] were developed

Thus the SFI and SEF were proposed for the rehabilita-tion sites in the present study since both indices are applicablefor estimating soil fertility under vegetation succession ofsecondary forest in humid tropical regions of Brazil [29 30]A principal component analysis showed the most importantPC scores and revealed the significant soil properties whichcontribute to the soil fertility under rehabilitation (Table 3)The values of Soil Fertility Index (SFI) and Soil EvaluationFactor (SEF) for rehabilitation sites and secondary forest (SF)for surface soils (0minus10 cm) and subsurface soils (30minus40 cm)were clearly explained in our previous study [28 45] Therelationship between PC1 score and SFI and between the PC1score and the SEF is shown in Figure 2 Based on Figure 2


Table 3 Factor loadings of surface and subsurface soil physicochemical properties principal component analysis (PCA) and results of PCAof the rehabilitated forest

Variables analyzedpH (H2O) SOM Total N CEC Exch Ca Exch Mg Exch K Exch Al Available P

clay silt sand contents and bulk densityValue PC1 PC2 PC3

Surface soils (0ndash10 cm)Contribution ratio () 344 292 127

Variables with a high positive factor loading (gt07) + Exch Al Available Pand silt Total N clay and SOM ND

Variables with a high negative factor loading (gt07) minus pH (H2O) and sand Bulk density ND

Contribution name of PC axisAvailable phosphorussoil acidity and soil

texture

Soil organic matterconstituent

Subsurface soils (30ndash40 cm)Contribution ratio () 344 293 103

Variables with a high positive factor loading (gt07) + Exch Al and silt Total N Exch K clayand SOM ND

Variables with a high negative factor loading (gt07) minus pH (H2O) sand andbulk density ND Exch Ca

Contribution name of PC axis Soil acidity and soiltexture

Cation retentioncapacity soil organicmatter constituent

Available nutrient

(+) = factor loading with a positive value (minus) = factor loading with a negative value and ND = not determined SOM = soil organic matter Total N = totalnitrogen Exch Ca Mg K and Al = exchangeable Ca Mg K and Al clay silt and sand = percentage of clay silt and sand

0

5

10

15

20

25

30

0

5

10

15

20

25

30

minus30 minus20 minus10 00 10 20 30PC1

0

5

10

15

20

minus20 minus15 minus10 minus05 00 05 10 15 20PC1

0

5

10

15

20

minus30 minus20 minus10 00 10 20 30

Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Surface soil Subsurface soil

Soil

Eval

uatio

n Fa

ctor

(SEF

)

minus15 minus10 minus05 00 05 10 15minus20 20PC1

Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)

r = 0789lowastlowast

r = minus0123

r = minus0370

r = 0052

Figure 2 Relationship between PC1 score derived from PCA analysis and the calculated Soil Fertility Index (SFI) and Soil Evaluation Factor(SEF) for surface and subsurface soils lowastlowastCorrelations are significant at 1 level using Pearson correlation matrix


00

50

100

150

200

minus20 minus10 00 10 20PC1


00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)

minus20 minus10 00 10 20 30minus30PC1

r = 0546lowastlowast r = 0437lowast

minus10 00 10 20minus20PC1

Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296

minus15 minus10 minus05 00 05 10 15 20minus20PC1

Surv

ival

()


0

20

40

60

80

100

r = 0477lowastlowast r = 0183

Figure 3 Relationship between PC1 score diameter at breast height (DBH) height and percentage of survival derived from surface andsubsurface soils lowastlowastlowastCorrelations are significant at 5 and 1 levels respectively using Pearson correlation matrix

there was a high positive correlation between the PC1 scoreand SFI at surface soils (119903 = 0789lowastlowast P lt 001) but nocorrelation was found at subsurface soils On the other handno correlation was found between the PC1 score and SEFfor both surface and subsurface soils Hence the resultsrevealed that SFI showed similarity factorswith the PC1 scoreindicating the applicability of SFI as an index which can beused for estimating soil fertility status in the present study

Nonetheless in order to determine the applicability ofthese indices for estimating soil fertility and site quality inrelation to survivorship and growth performance of plantedShorea macrophylla after enrichment planting the values ofthe PC1 score SFI and SEF at both surface and subsurfacesoil depths were further correlated with the tree growthparameters (diameter at breast height (DBH) and height)and survival of the planted Shorea macrophylla trees fromour previous study [18] The results revealed positive andmoderate correlations between the PC1 score and diameter

at breast height (DBH) and survival percentage at surfacesoils (119903 = 0546lowastlowast P lt 001 and 119903 = 0477lowast P lt 005resp) as shown in Figure 3 On the other hand there wasno correlation observed between PC1 score and the treeheight of S macrophylla at both surface and subsurfacesoils Meanwhile at subsurface soils there was a positivecorrelation obtained between PC1 score and diameter atbreast height (119903 = 0437lowast P lt 005) However no correlationwas found between the PC1 score and the survival percentageof the trees at subsurface soils (Figure 3) Based onTable 4 theresults indicated that there were high correlations betweenSFI and DBH height and percentage of survival at surfacesoils The correlation coefficient between the SFI and DBHheight and percentage of survival ranged from0483 to 0684The SFI was correlated with DBH (119903 = 0565lowastlowast P lt 001)height (119903 = 0483lowast P lt 005) and survival (119903 = 0684lowastlowast P lt001) at surface soils whereas no significant correlations werefound at subsurface soils for SFI (Figure 4) Moreover there


0

5

10

15

20

25

30

00 50 100 150 200Diameter at breast height (cm)


0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)


50 100 150 20000Diameter at breast height (cm)

r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()

r = 0684lowastlowast r = minus0014

Figure 4 Relationship between diameter at breast height (DBH) height and percentage of survival with Soil Fertility Index (SFI) derivedfrom surface and subsurface soils lowastlowastlowastCorrelations are significant at 5 and 1 levels respectively using Pearson correlation matrix

were no significant correlations observed between SEF andDBH height and survival percentage for both surface andsubsurface soils as shown in Figure 5 Hence these resultsshowed that the SFI is also one of the applicable indices todetermine soil fertility status as well as site quality in relationto the productivity of Shorea macrophylla planting in thisstudy Arifin et al [21] mentioned that SEF might not beappropriate for sandy texture soils such as in the presentstudy since the level of soil exchangeable cationswas relativelylower than that of soil exchangeable Al A brief summary ofthe relationship between PC1 score SFI SEF and tree growthparameters (diameter at breast height (DBH) and height) andpercentage of survival was shown in Table 4

Notwithstanding to predict the best indicator for esti-mating soil fertility and site quality in relation to survivorshipand growth performance of planted Shorea macrophylla afterenrichment planting the values of soil available phosphorus

content at the rehabilitation sites at both surface and subsur-face soil depths were correlated with tree growth parameters(diameter at breast height (DBH) and height) and survivalfrom our previous study [18] The results indicated thatthere was a strong relationship between the soil availablephosphorus and tree growth parameters diameter at breastheight height and percentage of survival as shown in Fig-ure 6 There were strong and moderate positive correlationsbetween the soil available phosphorus and diameter at breastheight at surface soils (119903 = 0678lowastlowast P lt 001) and subsurfacesoils (119903 = 0454lowast P lt 005) respectively Nonetheless apositive correlation was also observed between soil availablephosphorus and the height and survival percentage at surfacesoils (119903 = 0551lowastlowast and 119903 = 0676lowastlowast P lt 001 resp)Based on Figure 6 the soil available phosphorus is directlyproportional to the diameter at breast height tree heightand survival percentage of the planted S macrophylla in


0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)

Diameter at breast height (cm)

0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327

r = minus0086 r = minus0307

r = minus0240

r = minus0312

Figure 5 Relationship between diameter at breast height (DBH) height and percentage of survival with Soil Evaluation Factor (SEF) derivedfrom surface and subsurface soils

Table 4 Summary of the relationship between PC1 score SFI SEF and tree growth parameters (diameter at breast height (DBH) heightand percentage of survival)

Growthparameters

PC1 SFI SEF

Surface (0ndash10 cm) Subsurface(30ndash40 cm) Surface (0ndash10 cm) Subsurface

(30ndash40 cm) Surface (0ndash10 cm) Subsurface(30ndash40 cm)

DBH 0546lowastlowast 0437lowast 0565lowastlowast minus0043 minus0388 minus0312Height 0352 0296 0483lowast minus0053 minus0327 minus0240Survival 0477lowast 0183 0684lowastlowast minus0014 minus0086 minus0307lowastlowastlowastCorrelations are significant at 5 and 1 levels respectively using Pearson correlation matrix

the rehabilitation sites Consequently based on the resultsof correlation at surface soils it can be deduced that soilavailable phosphorus (DBH 119903 = 0678lowastlowast P lt 001 height119903 = 0551lowastlowast P lt 001) is clearly a better indicator of Smacrophylla productivity than the SFI (DBH 119903 = 0565lowastlowast Plt 001 and height 119903 = 0483lowast P lt 005) in the present study

According to our previous study [18 19] high contentof available phosphorus in soils was related to an increasein the growth and survival percentage of S macrophyllain SM96 and SM97 whereas the low content of availablephosphorus was related to a decrease in the growth andsurvival percentage of the planted trees in the SM98 and


00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332

Figure 6 Relationship between soil available phosphorus with diameter at breast height (DBH) height and percentage of survival derivedfrom surface and subsurface soils lowastlowastlowastCorrelations are significant at 5 and 1 levels respectively using Pearson correlation matrix

SM99 sites One possible reason for the poor growth rateof the planted S macrophylla (data not shown) especiallyin study sites SM98 and SM99 was probably due to thelow availability of soil phosphorus pools in the form oforganic and inorganic phosphorus in the bulk soil whichwould limit the uptake of plants Phosphorus is transportedprincipally by diffusion whereas soluble minerals such aspotassium K are transferred via the soil through bulk flowand diffusion High plant uptake rates create a zone aroundthe root which is depleted of P since the rate of P diffusionis slow [61] According to Perrott et al [62] and Frossardet al [63] the content of soil available P largely dependson a combination of factors including the uptake of plantadsorption-desorption and dissolution-precipitation of inor-ganic P organic P mineralization microbial immobilization

and addition of fertilizer Immobile forms of P to the soilsolution were released by soil microbes and the microbes areresponsible for the P immobilization [61] Likewise a studyconducted in unimproved grassland and 19-year-old stand byChen et al [64] concluded that the recycling of P was largelydriven by plant P demand and sustained by leaf litter inputsand root in forest ecosystems Environmental factors such asthe amount of rainfall soil temperature and moisture mightalso influence the availability of P

4 Conclusions and Recommendations

In conclusion the assessment on the status of soil physic-ochemical properties showed that the soil properties aresignificantly varied between the rehabilitation sites (SM96


SM97 SM98 and SM99) and secondary forest (SF) Gen-erally the soils in rehabilitation sites and secondary forestof Sampadi Forest Reserve could be categorized as stronglyacidic in nature pH (H2O) values of less than 550 with poorsoil exchangeable bases and low nutrient status at surfaceand subsurface soil layers The soils were relatively sandyranging from sandy clay loam to sandy clay in texture Soiltotal carbon and total nitrogen in the secondary forest weresignificantly higher than those of the rehabilitation sitesshowing that a large pool of fresh organic matter was derivedfrom the above vegetation in the surface and subsurface soilsPrincipal Component Analysis (PCA) generated three mostsignificant components which explained about 763 of thetotal variability and each component portrays a series ofvariables which simplifies the analysis and interpretationThefirst component score (PC1) represents phosphorus contentsoil acidity and soil texture Soil organic matter constituentand cation retention capacity represent PC2 whereas avail-able nutrient represents PC3 Pearson correlation analysisindicated that Soil Fertility Index (SFI) was highly correlatedwith PC1 score diameter at breast height (DBH) height andsurvival of the planted Shorea macrophylla trees at surfacesoils indicating the applicability of SFI as an index to estimateand quantify soil fertility and site quality under line plantingtechnique in the present study For practical purposes itcan be deduced that the SFI can be used as an index toassess the difference in growth of planted trees caused byvariability and heterogeneity of soil fertility levels of degradedforestland within a site Notwithstanding the results alsoshowed that there was a strong association between soilavailable phosphorus with tree growth parameters indicatingthat soil available phosphorus is a better indicator thanSFI in the present study Consequently it is recommendedthat in future further comprehensive studies on otherenvironmental factors including soil biological propertieswhich might influence the tree growth performance shouldbe implemented In addition early establishment of exper-imental reforestation at nursery and field trials should beundertaken in order to obtain the initial data on seedlinggrowth performance prior to outplanting

Disclosure

The research project was conducted under the supervisionof Dr Mohd Effendi Wasli and the project was run asMugunthan Perumalrsquos research project

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

This research was financially supported by the researchgrant from Fundamental Research Grant Scheme (FRGS)(E14099F07699892013(30)) from Ministry of HigherEducation Malaysia and a Universiti Malaysia Sarawak(UNIMAS) internal grant under the PhD Student Fund

(F07DPP56135320163) Grant-in-Aid for scientific re-search purpose by the Japan-Malaysia Association (JMA)and NPO Rainforest Sarawak The authors wish to expressgratitude to the Director and staff of the Forest DepartmentSarawak for their supportive assistance during the durationof this study The authors would also like to extend thanks tolocal villagers from the study area for their kind cooperationand assistance during the field survey

References

[1] P Panwar S Pal S K Reza and B Sharma ldquoSoil fertility indexsoil evaluation factor andmicrobial indices under different landuses in acidic soil of humid subtropical Indiardquo Communicationsin Soil Science and Plant Analysis vol 42 no 22 pp 2724ndash27372011

[2] ITTO Guidelines for the Restoration Management and Reha-bilitation of Degraded and Secondary Tropical Forests PolicyDevelopment Series 13 ITTO Yokohama Japan 2002

[3] J Ramos and S del Amo ldquoEnrichment planting in a tropicalsecondary forest in Veracruz Mexicordquo Forest Ecology andManagement vol 54 no 1ndash4 pp 289ndash304 1992

[4] G Adjers S Hadengganan J Kuusipalo K Nuryanto andL Vesa ldquoEnrichment planting of dipterocarps in logged-oversecondary forests effect of width direction and maintenancemethod of planting line on selected Shorea speciesrdquo ForestEcology and Management vol 73 no 1ndash3 pp 259ndash270 1995

[5] R Otsamo ldquoEffect of nurse tree species on early growth ofAnisoptera marginata Korth (Dipterocarpaceae) on an Imper-ata cylindrica (L) Beauv dominated grasslands site in SouthKalimantan Indonesiardquo Forest Ecology and Management vol105 no 1ndash3 pp 303ndash311 1998

[6] A Vincent and S J Davies ldquoEffects of nutrient additionmulching and planting-hole size on early performance of Dry-obalanops aromatica and Shorea parvifolia planted in secondaryforest in Sarawak Malaysiardquo Forest Ecology and Managementvol 180 no 1ndash3 pp 261ndash271 2003

[7] U Ilstedt A Malmer A Nordgren and P Liau ldquoSoil rehabil-itation following tractor logging early results on amendmentsand tilling in a second rotation Acacia mangium plantation inSabah Malaysiardquo Forest Ecology and Management vol 194 no1ndash3 pp 215ndash222 2004

[8] A E Lugo ldquoThe apparent paradox of reestablishing speciesrichness on degraded lands with tree monoculturesrdquo ForestEcology and Management vol 99 no 1-2 pp 9ndash19 1997

[9] J A Parrotta J W Turnbull and N Jones ldquoCatalyzing nativeforest regeneration on degraded tropical landsrdquo Forest Ecologyand Management vol 99 no 1-2 pp 1ndash7 1997

[10] M E McDill and R L Amateis ldquoTree growth in primarylowland and hill dipterocarp forestsrdquo Journal of Tropical ForestScience vol 6 pp 332ndash345 1992

[11] J C Onyekwelu ldquoSite index curves for site quality assessmentof Nauclea diderrichii monoculture plantations in Omo ForestReserve Nigeriardquo Journal of Tropical Forest Science vol 17 no4 pp 532ndash542 2005

[12] R Doi and K Sakurai ldquoPrincipal components derived from soilphysicochemical data explained a land degradation gradientand suggested the applicability of new indexes for estimationof soil productivity in the Sakaerat Environmental ResearchStationThailandrdquo International Journal of Sustainable Develop-ment ampWorld Ecology vol 11 no 3 pp 298ndash311 2004


[13] G Adjers J Kuusipalo S Hadengganan K Nuryanto and LVesa ldquoPerformance of ten dipterocarp species in restockinglogged-over forest areas subjected to shifting cultivationrdquo Jour-nal of Tropical Forest Science vol 9 no 2 pp 151ndash160 1996

[14] F Montagnini B Eibl L Grance D Maiocco and D NozzildquoEnrichment planting in overexploited subtropical forests of theParanaense region of Misiones Argentinardquo Forest Ecology andManagement vol 99 no 1-2 pp 237ndash246 1997

[15] A K Zaidey A Arifin I Zahari et al ldquoCharacterizing soilproperties of lowland and hill dipterocarp forests at PeninsularMalaysiardquo International Journal of Soil Science vol 5 no 3 pp112ndash130 2010

[16] J J Kendawang J Sabang S Tanaka et al ldquoEffects of shiftingcultivation on soil ecosystems in SarawakMalaysia I Slash andburning at Balai Ringin and Sabal experimental sites and effecton soil organic matterrdquo Soil Science amp Plant Nutrition vol 50no 5 pp 677ndash687 2004

[17] M E Wasli H Sani S Y Ho et al ldquoPreliminary assessment onthe growth performance ofDryobalanops beccariiDyer plantedunder enrichment planting technique at Gunung Apeng ForestReserverdquo Kuroshio Science vol 8 pp 45ndash52 2014

[18] M Perumal M E Wasli S Y Ho J Lat and H SanildquoSurvivorship and growth performance of Shorea macrophylla(de Vriese) after enrichment planting for reforestation purposeat Sarawak Malaysiardquo Online Journal of Biological Sciences vol17 no 1 pp 7ndash17 2017

[19] M Perumal M EWasli S Y Ho J Lat and H Sani ldquoSoil mor-phological and physicochemical properties at reforestation sitesafter enrichment planting of Shorea macrophylla in SampadiForest Reserve Sarawak Malaysiardquo Borneo Journal of ResourceScience and Technology vol 5 no 2 pp 28ndash34 2015

[20] S Appanah and G Weinland Planting Quality Timber Treesin Peninsular Malaysia Forest Research Institute of MalaysiaKepong Kuala Lumpur Malaysia 1993

[21] A Arifin S Tanaka S Jusop N M Majid Z Ibrahim andK Sakurai ldquoRehabilitation of degraded tropical rainforest inPeninsular Malaysia with a multi-storied plantation techniqueof indigenous dipterocarp speciesrdquo Japanese Journal of ForestEnvironment vol 50 pp 141ndash152 2008

[22] H Affendy M Aminuddin W Razak A Arifin and A RMojiol ldquoGrowth increments of indigenous species planted insecondary forest areardquo Journal of Forestry Research vol 3 no1 pp 23ndash28 2009

[23] M Z Hamzah A Arifin A K Zaidey et al ldquoCharacterizingsoil nutrient status and growth performance of planted dipte-rocap and non-dipterocarp species on degraded forest land inPeninsular Malaysiardquo Journal of Applied Sciences vol 9 no 24pp 4215ndash4223 2009

[24] D K Jha G D Sharma and R R Mishra ldquoSoil microbialpopulationnumbers and enzyme activities in relation to altitudeand forest degradationrdquo Soil Biology amp Biochemistry vol 24 no8 pp 761ndash767 1992

[25] M M Sena R J Poppi R T Frighetto and P J ValarinildquoAvaliacao do uso de metodos quimiometricos em analise desolosrdquo Quımica Nova vol 23 no 4 pp 547ndash556 2000

[26] J Domınguez M A Negrın and C M Rodrıguez ldquoSoilchemical characteristics in relation to fusarium wilts in bananacrops of Gran Canaria Island (Spain)rdquo Communications in SoilScience and Plant Analysis vol 27 no 13-14 pp 2649ndash26621996

[27] B D Seelig J L Richardson and R E Knighton ldquoComparisonof statistical and standard techniques to classify and delineate

sodic soilsrdquo Soil Science Society of America Journal vol 55 no4 pp 1042ndash1048 1991

[28] M Perumal M E Wasli and H Sani Relationship betweensoil fertility and growth performance of planted Shorea macro-phylla at reforestation sites of Sampadi Forest Reserve SarawakMalaysia [master thesis] Universiti Malaysia Sarawak KotaSamarahan Sarawak Malaysia 2014

[29] E F Moran E S Brondizio J M Tucker M C Da Silva-Forsberg S McCracken and I Falesi ldquoEffects of soil fertilityand land-use on forest succession in Amazoniardquo Forest Ecologyand Management vol 139 no 1ndash3 pp 93ndash108 2000

[30] D Lu EMoran and PMausel ldquoLinkingAmazonian secondarysuccession forest growth to soil propertiesrdquoLandDegradationampDevelopment vol 13 no 4 pp 331ndash343 2002

[31] J P Andriesse The Soils of West Sarawak (East Malaysia)l Memoir Ed Soils Division Department of AgricultureSarawak Malaysia 1972

[32] Meteorological Department Weather Data (Air Temperature)2001-2010 Meteorological Department Sarawak KuchingMalaysia 2010

[33] S C Teng Keys to Soil Classification of Sarawak AgricultureDepartment of Sarawak 2004

[34] Soil Survey Staff Keys to Soil Taxonomy US Departmentof Agriculture and Natural Resources Conservation ServicesWashington DC Wash USA 12th edition 2014

[35] Forest Department Sarawak ldquoPlanted Forests in Sarawakrdquo inProceedings of an International Conference pp 16-17 Sarawak Malaysia February 1998

[36] M E Wasli S Tanaka J J Kendawang et al ldquoVegetationconditions and soil fertility of fallow lands under intensifiedshifting cultivation systems in Sarawak Malaysiardquo Tropics vol18 no 3 pp 115ndash126 2009

[37] M E Sumner and B A Stewart Soil Crusting Chemical andPhysical Processes Lewis Publishers Boca Raton FL USA 1stedition 1992

[38] J A McKeague Manual on Soil Sampling and Methods ofAnalysis Canadian Soil Survey Committee Ottawa OntarioCanada 1976

[39] N C Banning C D Grant D L Jones and D V MurphyldquoRecovery of soil organic matter organic matter turnoverand nitrogen cycling in a post-mining forest rehabilitationchronosequencerdquo Soil Biology amp Biochemistry vol 40 no 8 pp2021ndash2031 2008

[40] J M Bremner and C S Mulvaney ldquoMethods of soil analysespart 2 chemical and mineralogical propertiesrdquo in Nitrogen-Total R H Miller and D R Keeney Eds pp 595ndash624 Amer-ican Society of Agronomy Soil Science Society of AmericaMadison WI USA 1982

[41] R H Bray and L T Kurtz ldquoDetermination of total organic andavailable forms of phosphorus in soilsrdquo Soil Science vol 59 no1 pp 39ndash46 1945

[42] S Kuo ldquoMethods of soil analysis part 3 chemical methodsrdquoin Phosphorus D L Sparks P N Page M A Tabatabai C TJohnston and M E Summer Eds SSSA Book Series no 5 pp869ndash919 Soil Science Society of America Inc and AmericanSociety of Agronomy Inc Wisconsin WI USA 1996

[43] G W Gee and J W Bauder ldquoMethods of soil analysis part 1physical and mineralogical methodsrdquo in Particle-Size AnalysisA Klute Ed pp 399ndash404 Soil Science Society of America Incand America Society of Agronomy Inc Madison WI USA2nd edition 1986


[44] K H Tan Soil Sampling Preparation and Analysis Taylor andFrancis 2nd edition 2005

[45] M Perumal M E Wasli and J Lat ldquoEstimating soil fertilitystatus using soil quality indices at reforestation sites in SampadiForest Reserve Sarawak Malaysiardquo in Proceedings of the 2ndRegional Taxonomy and Ecology Conference I Jusoh I Ipor AS A Puad andRHassan Eds pp 275ndash287UniversitiMalaysiaSarawak Sarawak Malaysia 2016

[46] A Arifin S Tanaka S Jusop et al ldquoSoil characteristics underrehabilitation of degraded forest land in Perak PeninsularMalaysiardquo Pedologist vol 51 pp 76ndash88 2007

[47] S Tanaka S Tachibe M E B Wasli et al ldquoSoil characteristicsunder cash crop farming in upland areas of Sarawak MalaysiardquoAgriculture Ecosystems amp Environment vol 129 no 1ndash3 pp293ndash301 2009

[48] S Tanaka M E Wasli T Kotegawa et al ldquoSoil propertiesof secondary forests under shifting cultivation by the Iban ofSarawak Malaysia in relation to vegetation conditionrdquo Tropicsvol 16 no 4 pp 385ndash398 2007

[49] S Ohta K Morisada N Tanaka Y Kiyono and S Effendi ldquoAreSoils inDegradedDipterocarp Forest EcosystemsDeterioratedA Comparison of Imperata Grasslands Degraded SecondaryForests and Primary Forestsrdquo in Rainforest Ecosystems of EastKalimantan vol 140 of Ecological Studies pp 49ndash57 SpringerJapan Tokyo 2000

[50] J Boonyanuphap K Sakurai and S Tanaka ldquoSoil nutrientstatus under upland farming practice in the Lower NorthernThailandrdquo Tropics vol 16 no 3 pp 215ndash231 2007

[51] M H Akbar O H Ahmed A S Jamaluddin et al ldquoDifferencesin soil physical and chemical properties of rehabilitated andsecondary forestsrdquo American Journal of Applied Sciences vol 7no 9 pp 1200ndash1209 2010

[52] P H Nye andD J Greenland ldquoChanges in the soil after clearingtropical forestrdquo Plant and Soil vol 21 no 1 pp 101ndash112 1964

[53] S Ishizuka S Tanaka K Sakurai et al ldquoCharacterizationand distribution of soils at Lambir Hills National Park inSarawak Malaysia with special reference to soil hardness andsoil texturerdquo Tropics vol 8 no 12 pp 31ndash44 1998

[54] A S R Juo and A Manu ldquoChemical dynamics in slash-and-burn agriculturerdquo Agriculture Ecosystems amp Environment vol58 no 1 pp 49ndash60 1996

[55] C P Giardina R L Sanford Jr I C Doslashckersmith and V JJaramillo ldquoThe effects of slash burning on ecosystem nutrientsduring the land preparation phase of shifting cultivationrdquo Plantand Soil vol 220 no 1-2 pp 247ndash260 2000

[56] W Etsuko K Sakurai Y Okabayashi L Nouanthasing and AChanphengxay ldquoSoil fertility and farming systems in a slashand burn cultivation area of Northern Laosrdquo Southeast AsianStudies vol 41 no 4 pp 519ndash537 2004

[57] S Ohta S Effendi N Tanaka S Miura S Ohta and S EffendildquoUltisols of lowland Dipterocarp forest in East KalimantanIndonesia III Clay minerals free oxides and exchangeablecationsrdquo Soil Science amp Plant Nutrition vol 39 no 1 pp 1ndash121993

[58] B Soto and F Diaz-Fierros ldquoInteractions between plant ashleachates and soilrdquo International Journal of Wildland Fire vol3 no 4 pp 207ndash216 1993

[59] S Ohta and S Effendi ldquoUltisols of rsquolowland Dipterocarp forestrsquoin East Kalimantan Indonesia II Status of carbon nitrogenand phosphorusrdquo Soil Science amp Plant Nutrition vol 38 no 2pp 207ndash216 1992

[60] P T Alvim and F P C Rosand ldquoUm novo sistema derepresentacao grafica da fertilidade de solos para cacaordquo CacaoAtualidades vol 11 pp 2ndash6 1974

[61] D P Schachtman R J Reid and S M Ayling ldquoPhosphorusuptake by plants from soil to cellrdquo Plant Physiology vol 116 no2 pp 447ndash453 1998

[62] K W Perrott S U Sarathchandra and J E Waller ldquoSeasonalstorage and release of phosphorus and potassium by organicmatter and the microbial biomass in a high-producing pastoralsoilrdquo Australian Journal of Soil Research vol 28 no 4 pp 593ndash608 1990

[63] E Frossard L M Condron A Oberson S Sinaj and JC Fardeau ldquoProcesses governing phosphorus availability intemperate soilsrdquo Journal of Environmental Quality vol 29 no1 pp 15ndash23 2000

[64] C R Chen L M Condron M R Davis and R R SherlockldquoSeasonal changes in soil phosphorus and associated microbialproperties under adjacent grassland and forest inNewZealandrdquoForest Ecology and Management vol 177 no 1ndash3 pp 539ndash5572003

Submit your manuscripts athttpswwwhindawicom

Forestry ResearchInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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International Journal of


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BiodiversityInternational Journal of


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OceanographyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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ClimatologyJournal of


or stand for the purpose of environmental conservation[15] Rehabilitation efforts in degraded forestland due toabandoned shifting cultivation have been successfully imple-mented under the ecosystem rehabilitation [16] and byenrichment planting technique [17 18] in Sarawak MalaysiaIn Sarawak one of the common indigenous tree species fromDipterocarpaceae family Shoreamacrophylla (de Vriese) wasconsidered and selected for forest rehabilitation purposes[18 19] This climax species was chosen since it is one ofthe fastest growing species of the genus Shorea and is foundfrequently along rivers and in areas which are periodicallyinundated Likewise in Peninsular Malaysia rehabilitationof forestland that is degraded due to excessive harvestinghas been reforested through the technique of enrichmentplanting [20ndash23]

Knowledge of soil science for the better understanding ofthe effective soil management and conservation is requiredfor the rehabilitation of tropical rainforest on the land that isseverely degraded Consequently a multivariate strategy canbe implemented to measure the soil quality Since propertiesof the same soil may respond differently to a degradingimpact [24] it is expected to be more informative to quantifyand integrate various soil variables than measuring a singlevariable [12] A multivariate soil data set is regarded asintegrated properties of the soil According to Sena et al [25]integrating multiple soil physicochemical properties with theuse of a multivariate statistical technique often provides newmeasures that explain variations among the soils

Principal Component Analysis (PCA) is one of the pro-posedmultivariate statistical techniques used tomeasure andexplain the differences among soils In PCA a multivariatedata set is analyzed to reduce the original complicateddimensionality and to give a few principal components (PCs)that explain the variation in the data [12 21] Thus dataredundancy is avoided and the most significant PCs whichexplain the difference are specified Previous studies haveemphasized using PCA to identify PCs and important soilphysicochemical properties relating to the incidence of plantdisease [26] soil formation reflecting landscape [27] andother types of gradient

However for the case of Sarawak Malaysia intensiveresearch has to be done on the elucidation of soil prop-erties based on PCA and soil indices after enrichmentplanting in relation to the productivity of the potentialdipterocarp species in rehabilitating degraded forestlandMoreover attention has to be paid to the status of soilphysicochemical properties after rehabilitation since most ofthe previous researches have underlined the growth perfor-mance of planted species along with the different techniqueof planting [19 28] In addition information on the soil-plant relationship of indigenous species and soil fertilitystatus which might influence the survivorship and growthperformance of planted species under rehabilitation evenafter 14 years of the research is necessary for future forestmanagement programmes On the other hand Hamzah etal [23] stated that more comprehensive research has to beconducted on site productivity which could be improved byclarifying the potential of dipterocarp species in rehabilitatingdegraded forestland

Therefore in order to improve strategies and effectivetechnique for future rehabilitation efforts an evaluation studyof the rehabilitation programme in relation to growth per-formance of planted species and soil fertility status by usingPCA and soil indices could deliver significant information onspecies site preference [21]Themain emphasis was placed onfinding the significant soil properties based on PCA and theapplicability of the proposed indices the Soil Fertility Index(SFI) [29] and the Soil Evaluation Factor (SEF) [30] as analternative approach of indicator for estimating soil fertilityand site quality in the plantation for rehabilitation purposesin relation to the survivorship and growth performanceof the planted species Lu et al [30] mentioned that fora homogeneous forest with similar vegetation ages soilindices are often used to evaluate the soil conditions andthe dominant tree height is usually used to model the siteindices

Hence the aim of this studywas to determine the status ofsoil physicochemical properties under enrichment plantingin comparison to an adjacent secondary forest at SampadiForest Reserve Lundu Sarawak Malaysia In addition thepresent study also intended to evaluate the effect of enrich-ment planting of Shorea macrophylla (de Vriese) on the soilfertility status with special reference to Soil Fertility Index(SFI) and Soil Evaluation Factor (SEF) These indices sug-gested the applicability to the estimation of soil fertility andto the prediction of the increase in biomass in Amazonianhumid tropical forests under secondary successionThe scoreon the PC as a measure of changes of soil physicochemicalproperties after enrichment planting correlates with the SFIandor the SEF was investigated

2 Materials and Methods

21 Background and Information on Sampadi Forest ReserveRehabilitation Sites and Secondary Forest The presentstudy was conducted in a forest under enrichmentplanting at Sampadi Forest Reserve Lundu Sarawak(N01∘3410158401310158401015840E109∘5310158401210158401015840) and adjacent secondary forest(N01∘30101584026210158401015840E109∘58101584056710158401015840) which is located about 72 kmsouthwest of Kuching City (Figure 1)The area covers approx-imately 5163 hectares with an average elevation of 87mabove sea level The topography at the rehabilitation sitesand secondary forest is of the low undulating type SampadiForest Reserve has a humid subtropical seasonal climateand wet forest biozone (no dry season) with all monthsreceiving on average more than 100mm of precipitation[6] In the early hours of the morning the average surfaceannual temperature in the area is 22∘C (72∘F) and duringmid-afternoon it rises to around 31∘C (88∘F) with littlemonthly variation [31 32] According to our previous studyat the area the morphological characteristics of the soilsresemble Bako soil series as a dominant unit in associationwith Saratok series and are categorized mainly under the soilgroup of Grey-White Podzolic Soil based on the Sarawaksoil classification system [19 31] The soils in the study areawere derived from a mixture of sandstone coarse-grainedhumult ultisols and sandy residual parent material [19 28]Based on the USDA-NRCS classification system this soil




Sarawak

South China Sea

Brunei

Saba

h

Kuching

Sarawak

W E

N

S(m)

(km)30

Scale 1 2000000





















(1)








(2)













minus1












(a)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF










(b)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF









(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF
























texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in

























Sarawak

South China Sea

Brunei

Saba

h

Kuching

Sarawak

W E

N

S(m)

(km)30

Scale 1 2000000





















(1)








(2)













minus1












(a)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF










(b)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF









(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF
























texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in




































(1)








(2)













minus1












(a)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF










(b)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF









(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF
























texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in





























(2)













minus1












(a)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF










(b)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF









(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF
























texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in
























(a)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF










(b)



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF









(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF
























texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in























(b) Continued



(18 years)SM97

(17 years)SM98

(16 years)SM99

(15 years)SF
























texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in






































texture







Available nutrient


0

5

10

15

20

25

30

0

5

10

15

20

25

30


0

5

10

15

20


0

5

10

15

20


Soil

Eval

uatio

n Fa

ctor

(SEF

)

PC1

SM96SM97

SM98SM99

SM96SM97

SM98SM99


Soil

Eval

uatio

n Fa

ctor

(SEF

)


Soil

Fert

ility

Inde

x (S

FI)

Soil

Fert

ility

Inde

x (S

FI)


r = minus0123

r = minus0370

r = 0052



00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in























00

50

100

150

200



00

50

100

150

200

00

50

100

150

00

50

100

150

0

20

40

60

80

100

Surv

ival

()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Dia

met

er at

bre

ast h

eigh

t (cm

)

Dia

met

er at

bre

ast h

eigh

t (cm

)




Hei

ght (

m)

Hei

ght (

m)

r = 0352


r = 0296


Surv

ival

()


0

20

40

60

80

100







0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in























0

5

10

15

20

25

30



0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Fert

ility

Inde

x (S

FI)



r = minus0043

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = 0483lowast

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

50 100 15000Height (m)

r = minus0053

20 40 60 80 1000Survival ()

0

5

10

15

20

25

30

Soil

Fert

ility

Inde

x (S

FI)

0

5

10

15

20

Soil

Fert

ility

Inde

x (S

FI)

20 40 60 80 1000Survival ()







0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in























0

5

10

15

20



0

5

10

15

20

00 50 100 150Height (m)

0

5

10

15

20

0 20 40 60 80 100Survival ()

0

5

10

15

00 50 100 150 200

Soil

Eval

uatio

n Fa

ctor

(SEF

)


0

5

10

15

00 50 100 150So

il Ev

alua

tion

Fact

or (S

EF)

Height (m)

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

Eval

uatio

n Fa

ctor

(SEF

)So

il Ev

alua

tion

Fact

or (S

EF)

Soil

Eval

uatio

n Fa

ctor

(SEF

)

0

5

10

15

Soil

Eval

uatio

n Fa

ctor

(SEF

)

20 40 60 80 1000Survival ()

r = minus0388

r = minus0327


r = minus0240

r = minus0312



Growthparameters

PC1 SFI SEF







00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in























00

50

100

150

200



00

50

100

150

200

00 50 100 150Height (m)

00

50

100

150

200

0 20 40 60 80 100Survival ()

00

20

40

60

80

100


00

20

40

60

80

100

00 50 100 150Height (m)

00

20

40

60

80

100

0 20 40 60 80 100Survival ()

SM96SM97

SM98SM99

SM96SM97

SM98SM99

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)

Soil

avai

labl

e pho

spho

rus

(mgP

kＡminus1)




r = 0332








Disclosure




Acknowledgments



References








































































Journal of










Advances in
























Disclosure




Acknowledgments



References








































































Journal of










Advances in

















































































Journal of










Advances in






















Association between Soil Fertility and Growth...

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