The Effects of Biochar and Its Combination with Compost on...

Research ArticleThe Effects of Biochar and Its Combination withCompost on Lettuce (Lactuca sativa L) Growth Soil Propertiesand Soil Microbial Activity and Abundance

Dalila Trupiano1 Claudia Cocozza1 Silvia Baronti2 Carla Amendola1

Francesco Primo Vaccari2 Giuseppe Lustrato1 Sara Di Lonardo2 Francesca Fantasma1

Roberto Tognetti1 and Gabriella Stefania Scippa1

1Dipartimento di Bioscienze e Territorio Universita degli Studi del Molise 86090 Pesche Italy2Istituto di Biometeorologia-Consiglio Nazionale delle Ricerche (IBIMET-CNR) 50145 Firenze Italy

Correspondence should be addressed to Dalila Trupiano dalilatrupianounimolit

Received 16 December 2016 Revised 6 March 2017 Accepted 19 March 2017 Published 5 April 2017

Academic Editor Ibrokhim Y Abdurakhmonov

Copyright copy 2017 Dalila Trupiano et alThis is an open access article distributed under the Creative CommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Impacts of biochar application in combination with organic fertilizer such as compost are not fully understood In this studywe tested the effects of biochar amendment compost addition and their combination on lettuce plants grown in a soil poor innutrients soil microbiological chemical and physical characteristics were analyzed together with plant growth and physiologyAn initial screening was also done to evaluate the effect of biochar and compost toxicity using cress plants and earthworms Resultsshowed that compost amendment had clear and positive effects on plant growth and yield and on soil chemical characteristicsHowever we demonstrated that also the biochar alone stimulated lettuce leaves number and total biomass improving soil totalnitrogen and phosphorus contents as well as total carbon and enhancing related microbial communities Nevertheless combiningbiochar and compost no positive synergic and summative effects were observed Our results thus demonstrate that in a soil poorin nutrients the biochar alone could be effectively used to enhance soil fertility and plant growth and biomass yield However wecan speculate that the combination of compost and biochar may enhance and sustain soil biophysical and chemical characteristicsand improve crop productivity over time

1 Introduction

Soil fertility degradation caused by erosion and depletion orimbalance of organicmatternutrients is affectingworld agri-cultural productivity [1] Inorganic fertilizers have played asignificant role in increasing crop production since the ldquogreenrevolutionrdquo [2] however they are not a sustainable solutionfor maintenance of crop yields [3] Long-term overuse ofmineral fertilizers may accelerate soil acidification affectingboth the soil biota and biogeochemical processes thus posingan environmental risk and decreasing crop production [4]Organic amendments such as compost and biochar couldtherefore be useful tools to sustainably maintain or increasesoil organic matter preserving and improving soil fertilityand crop yield

Biochar is a carbon-rich material obtained from thermo-chemical conversion (slow intermediate and fast pyrolysis orgasification) of biomass in an oxygen-limited environmentIt can be produced from a range of feedstock includingforest and agriculture residues such as straw nut shellsrice hulls wood chipspellets tree bark and switch grass[5] Biochar has been described as a possible tool for soilfertility improvement potential toxic element adsorptionand climate change mitigation [6ndash8]

Indeed several studies have shown that biochar appli-cation to soil can (i) improve soil physical and chemicalproperties [9 10] (ii) enhance plant nutrient availability andcorrelated growth and yield [11 12] (iii) increase microbialpopulation and activities [13ndash15] and (iv) reduce greenhousegas emissions through C sequestration [16]

HindawiInternational Journal of AgronomyVolume 2017 Article ID 3158207 12 pageshttpsdoiorg10115520173158207

2 International Journal of Agronomy

Table 1 Biochar and compost characteristics The complete biochar and compost characterization and related methods are detailed inAmendola et al [31] and Alfano et al [30] respectively All concentrations refer to dry matter and represent the means of three replicates plusmnstandard error

Biochar CompostpH 97 plusmn 01 75 plusmn 01Alkalinity ( CaCO

3) 182 plusmn 07 65 plusmn 04

EC (dSm) 75 plusmn 04 49 plusmn 03Moisture (gkg) 624 plusmn 13 34 plusmn 09CEC (cmolkg) 213 plusmn 02 210 plusmn 02Ptot (gkg) 122 plusmn 30 55 plusmn 06Ntot (gkg) 91 plusmn 02 120 plusmn 40Ctot (gkg) 7781 plusmn 00 3372 plusmn 03CN 1255 281Cultivable aerobic bacteria (log CFUg) Absent 76 plusmn 03Eumycetes (log CFUg) Absent 49 plusmn 01Actinomycetes (log CFUg) Absent 518 plusmn 02Coliform bacteria (log CFUg) Absent AbsentE coli (log CFUg) Absent AbsentSalmonellae spp (log CFUg) Absent Absent

The beneficial effects of biochar on plant productivity andsoil microbial population are related to the improvement ofspecific surface area cation exchange capacity bulk densitypH water and nutrients within the soil matrix [17] Besidethe generally positive plant growth responses to biocharamendment especially in acidic coarse texture soil negligibleor negative effects also occur due to types of feedstockand pyrolysis process biochar application rate plant speciesand soil characteristics [18 19] Furthermore in most casesbiochar does not provide high amounts of nutrients [20 21]

Some recent studies have indicated that combined appli-cations of biochar with organic or inorganic fertilizers couldlead to enhanced soil physical chemical and biologicalproperties as well as plant growth In particular several com-posted materials represent a sustainable source of availablenutrients that could enhance plant growth ameliorating soilphysicochemical characteristics and microbiological proper-ties [22ndash26] Liu et al [26] showed that the combined applica-tion of compost and biochar had a positive synergistic effecton soil nutrient contents and water-holding capacity underfield conditions In addition the combination of biochar withcompost has proved to be suitable allowing the reduction offertilizer inputs stabilizing the soil structure and improvingits nutrient content and water retention capacity [27 28]Again these studies underline that compost and biocharcombination could enhance compost properties leading toa higher added value and a much better carbon sequestrationpotential due to the long-term stability of biochar [24 25]

However the literature shows that compost effects as alsoreported above for biochar can differ on soil biophysical-chemical properties and plant growth and yield on the basisof feedstock types methods of producing and application[29] The objectives of this study were thus to determine theeffect of biochar application alone obtained from orchardpruning biomass by slow pyrolysis (550∘C) or combinedwith compost obtained from olive mill residues on (i) plant

growth physiology and yield (ii) soil chemical character-istics and (iii) soil microbiological abundance and enzymeactivities For this purpose a short-term potting experimentwas performed using Lactuca sativa L as reference plantsand a soil poor in nutrients as growing substrate to testthe following hypotheses biochar addition together withcompost improves (1) soil chemical and (2) microbiologicalproperties and enhances (3) plant growth and physiologymore than compost and biochar alone

2 Materials and Methods

21 Biochar Compost and Toxicity Test The biochar usedwas a commercial charcoal (provided by Romagna Carbonesnc Italy) obtained fromorchard pruning biomass througha slow pyrolysis process at a temperature of 500∘C in atransportable ring kiln 22m in diameter that holds around2 t of feedstock

An olive waste compost was used prepared in a specificexperimental composting process following Alfano et al[30] Briefly compost was prepared mixing humid olivehusks from a two-phase extraction plant with olive leaves(8ww) one-year-old humid composted husks (25ww)were then added to this mixture Biochar and compost char-acteristics are summarized in Table 1 and analytical methodsare provided in Amendola et al [31] and Alfano et al [30]

Biochar and compost phytotoxicity was assessed throughthe germination index (GI) of cress plants (Lepidiumsativum L) [26] Three different solutions were used toevaluate the biochar and compost toxicity on seed ger-mination sterile deionized water as control solution andsolutions containing 50 and 75 extract of biochar orcompost Solutions were added to Petri dishes containing10 sterile seeds of L sativum Germination percentage andplant root length were recorded after incubation for 42 hat 27∘C in the dark (according to Vitullo et al [32]) Seeds

International Journal of Agronomy 3

were scored as germinated if the radicle exceeded the lengthof the longest seed coat dimension The seed germinationpercentage was assessed according to the formula GI =(119866119904119871119904)(119866119888119871119888) times 100 where 119866

119904and 119871

119904are seed germination

and root elongation (mm) for the samples and 119866119888and 119871

119888

the corresponding values for controls The test was repeatedin triplicate The GI was obtained by means of GI

50 andGI75 values Potential toxicity of biochar was also tested

on earthworms (Lumbricus terrestris L) For the earthwormavoidance test equal amounts of unfertilized soil with andwithout biochar (65 g kgminus1 of dry soil) were placed in twohalves of a pot (50 times 30 cm) Forty earthworms were releasedbetween the two substrates After 48 hours the pot wasexamined to determine the soil selected by earthworms [33]

22 Experimental Design One-month-old lettuce (Lactucasativa L var longifolia) seedlings (Vivaio MignognaRipamolisana Molise Italy) were transplanted into plasticpots (35 l) prepared with four different substrates (i) unfer-tilized soil (PS) (ii) unfertilized soil plus compost (PSC)(iii) unfertilized soil plus biochar (PSB) and (iv) unfertilizedsoil plus compost and biochar (PSCB) Plants were thengrown until maturity (9 weeks) in a screened greenhouse(University of Molise Pesche Italy Lat 41∘3710158400010158401015840N Long14∘1710158400010158401015840E 510m asl) under a controlled water regimetemperatures ranging between 12 and 25∘C and natural daylength corresponding to spring-summer season (MayndashJuly)Soil was collected from an uncultivated pasture area locatedin Pesche with a floral composition predominantly ofgraminoid grasses not under a rotation system and thatincludes hedges This area is mainly used for grazingbut the fodder is harvested mechanically The preplantingphysicochemical properties of the soil are given in SupportingInformation (Table S1 in Supplementary Material availableonline at httpsdoiorg10115520173158207) Briefly thesoil was moderately subalkaline (0ndash30 cm) with a clay textureaccording to United States Department of Agricultureclassification [34] it was characterized by low electricalconductivity (EC) cation exchange capacity (CEC) andnitrogen and carbon content it is unlikely that this soilalready contained charcoal as there had been no traditionof crop residue or other burning on the land For theexperiment soil was air-dried for 72 h weighed and finelycrushed and then mixed thoroughly before packing lightlyin the pots on top of 100 g of pebbles placed on the base toimprove drainage The weight of each filled pot was 3000 g

Biochar and compost application rates were set up onthe basis of previous lettuce pot and field researches [12 35ndash39] In detail data reported by Carter et al [35] showed that50 and 150 g kgminus1 rice-husk biochar application rate led to ahighly positive effect on lettuce growth in compost fertilizedand unfertilized soils respectively Based on this finding inthe present study biochar and compost were supplied at anapplication rate of 65 g and 50 g per kg of dry soil respectivelyAfter mixing the pots were filled in order to ensure the samesoil bulk density There were ten pots (one plant per pot)for each treatment arranged in a complete randomized blockdesign and rotated each day to a different position within

the block for the duration of the trial The pots were fullyirrigated to prevent water stress (twice a day as required) anda suspended shade cover net was used to reduce exposure tosunlight

23 Soil Analyses Soils were sampled at the end of the exper-iment and air-dried for 72 h The moisture content was cal-culated according to the Black method [40] as the differencein sample weight before and after oven drying to constantweight at 105∘C The pH was measured by potentiometry(pH meter Eutech Instruments) in H

2O and 001M CaCl

2

using a 1 25 soil weight extract-volume ratio Alkalinity ofsamples with a pH value greater than 70 was determined bytitrimetry according to the Higginson and Rayment method[41 42] Electrical conductivity (EC) was determined by aconductivity meter (Cond 510 XS Instruments) on a 1 5soil water suspension [41 42] Ash content was determinedby igniting an oven-dried sample in a muffle furnace at 440plusmn 40∘C according to the American Society for Testing andMaterials [43] Cation exchange capacity (CEC) was assessedaccording Mehlich [44] using the BaCl

2 For total nitrogen

(Ntot) determination amodified Kjeldahl procedure was usedwith Devardarsquos alloy pretreatment important to recover bothNO3

minus-N and NO2

minus-N [45] Total phosphorus (Ptot) wasdetected by spectrophotometry (UV-1601 Shimadzu) accord-ing to the test method described by Bowman [46] Availablephosphorus (Pav) was extracted by a NaHCO

3solution at

pH 85 and evaluated by spectrophotometry according tothe Olsen test method [47] Total carbon (Ctot) content wasdetermined using a CHN autoanalyzer (CHN 1500 CarloErba) [48]

24 Plant Analysis Plant morphological analyses were per-formed weekly by measuring the main leaf parametersnumber (LN) area (LA) length (LL) width (LW) andperimeter (LP) The Image J 141 (httpsrsbinfonihgovij)software was used for analysis In addition at the end of theexperiment leaf and root biomass allocation was determinedbefore (fresh weight FW) and after (dry weight DW) twodays of drying in an oven at 60∘C The measurements wereperformed on six plants

Leaf water potential (120595) was measured using a pressurechamber (PMS Instrumentation Co Corvallis OR USA)Leaf gas exchange measurements were performed using aportable gas exchange system (CIRAS-1 PP Systems HertzHitchinUK) Leaf gas exchanges and120595weremeasured on thefourth fully expanded and sun exposed leaf on a cloud-freeday (after 3 months of growth) These measurements weretaken on five plants (one leaf per plant) per treatment aroundmidday (between 1130 am and 130 pm)

Chlorophyll content was also measured For this chloro-phylls 119886 (Chl119886) and 119887 (Chl119887) were extracted from threerandomly sampled leaf discs (10mm) with NN dimethyl-formamide (DMF) Extraction was performed for 48 h at4∘C in the dark at a ratio of 1 20 (plant material solventw v) [49] The extinction coefficients proposed by Inskeepand Bloom [50] were used for the quantification by spec-trophotometric analysis The following formulas were usedChl a = 1270

1198606645minus 279

119860647 Chl b = 2070

119860647minus 462

1198606645


Chl = 1790119860647

+ 8081198606645

where A is absorbance in 100 cmcuvettes and Chl is mg per l The leaf area Chl content wasthen calculated (mg cmminus2) together with the Chl aChl b ratioby dividing the Chl a content by the Chl b content

25 Microbiological Analyses Cellular cultivability wasassessed by plate-counting Cultivable aerobic bacteria insoil samples were analyzed on standard plate count agar(Difco Bekton Dikson Milan Italy) at 28 and 55∘C for 48 hactinomycetes on actinomyces agar (Difco) at 28∘C and55∘C for 48ndash72 h eumycetes on malt agar (Difco) + rosebengal 33mg lminus1 and tetracycline 100ml lminus1 at 28∘C for 72 hfollowing themethod described by Alfano et al [30] Cellularcounts were done in triplicate by performing quantitativedeterminations on the basis of colony forming units (CFU)in agarized media according to Alfano et al [30] All resultsare expressed as log CFUg DW after drying aliquots of thesamples at 105∘C for 48 h

Soil enzymatic activities were determined by the API-ZYM system (bio-Merieux Italia Rome Italy)With the API-ZYM system semiquantitative evaluation of the activities of19 hydrolytic enzymes [alkaline phosphatase esterase (C4)esterase-lipase (C8) lipase (C14) leucine arylamidase valinearylamidase cystine arylamidase trypsin 120572-chymotrypsinacid phosphatase phosphoamidase 120572-galactosidase 120573-gal-actosidase 120573-glucuronidase 120572-glucosidase 120573-glucosidaseN-acetyl-120573-glucosaminidase 120572-mannosidase and 120572-fucosi-dase] was determined [51 52] Using a sterile Pasteur pipetteeach gallery was inoculated with two drops of 10minus1 or 10minus2suspensions of 20 g of soil in 180mL of sterile saline solution(09NaCl wv)The color that developed in each enzymaticreaction was assigned according to the color chart (range0ndash5) supplied with the system and this in accordance withreported procedures provided the conversion evaluation ofthe hydrolyzed substrates in nanomoles [51] The sampleswere analyzed in triplicate and the average data were usedResults were expressed as enzyme relative activityg of DWof substrate data were corrected by the dilution factor

26 Statistical Analysis Analysis of variance (ANOVA) wasapplied in order to evaluate the effect of each treatment on soilproprieties chlorophyll ecophysiology and microbiologicaldata (one-way ANOVA) and the effect of day treatments andtheir interaction (two-way ANOVA) for plant morphologicaldata To assess the differences in the measured parametersamong treatments a postmeans comparison was performedusing the Fisher least significant difference (LSD) test atthe 005 significance level Statistical analysis was conductedwith OriginPro version 851 (OriginLab Northampton MAUSA)

3 Results

31 Biochar and Compost Characteristics Biochar and com-post used for the experiment were previously analyzed byAmendola et al [31] and Alfano et al [30] respectivelyMain biochar and compost characteristics are summarized inTable 1 Briefly as in the majority of biochar the pH value

PS0

5

10

15

20

25

30

35

40

Eart

hwor

ms n

umbe

r

lowast

SamplesPSB

Figure 1 Earthworms avoidance test Number of earthworms (Lum-bricus terrestris L) recovered in unfertilized (PS) versus unfertilizedplus biochar (PSB) soil compartments after 48 h Vertical bars rep-resent the standard error of the mean of three replicates of 40 earth-worms each Asterisks indicate significant differences (119901 le 005)

was within the range of alkalinity The Ctot and Ntot contentsof biochar were 778 and 09 respectively according toClass 1 of the Guidelines for Certification of the Interna-tional Biochar Initiative (IBI httpwwweuropean-biocharorgenebc-ibi) The compost was mature showing stablechemical andmicrobiological characteristics with the poten-tial to be used as an agricultural substrate or soil conditioner

The results showed that biochar was not toxic for soilbiotic communities L sativum seeds or earthworms Indeedthe phytotoxicity test with Lepidium showed no effects ofbiochar and compost on the germination index (82plusmn 4 and 95plusmn 4 resp) compared to the control (water 100 plusmn 2) (datanot shown) while the avoidance test showed that L terrestrispreferred the biochar-amended soil (Figure 1)

32 Soil Characterization Soil chemical analysis showed thatthe addition of biochar induced a significant increase of pHvalues from 69 (PS) to 80 and from 75 (PSC) to 77 in PSBand PSCB respectively On the contrary the alkalinity valuedid not change in PSB and PSCB compared to PS and PSCrespectively (Table 2)

An increase of total N content from 08 (PS) to 12 wasobserved in PSB Conversely the EC increased about 14and 11 fold in PSB and PSCB respectively while moisturedecreased 08-fold in PSCB Ash content slightly decreased inPSB and PSCB The Ptot was increased about 15-fold in PSBwhereas no alterationwas observed in PSBCOn the contrarythe Pav was 2-fold greater in PSCB than PSCThe Ctot contentwas significantly increased in PSB (5-fold) and PSCB (2-fold)compared to the relative controls (PS and PSC) The CECvalue was also slightly increased in PSB and PSCB comparedto PS and PSC respectively All the above parameters wereincreased in PSCB compared to PSB except for pHmoistureand ash that decreased

33 Plant Growth Significant differences in growth parame-ters were recorded between treatments (Figure 2) In detaillettuce plants showed higher leaf number in PSB than PS


PSPSB

PSCPSCB

0

5

10

15

20

25

LL (c

m)

1 2 3 4 5 6 7 8 9Time (weeks)

ns

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowastlowastlowastlowast

lowastlowast

PSPSB

PSCPSCB

1 2 3 4 5 6 7 8 9Time (weeks)

0

10

20

30

40

50

60

LP (c

m)

ns

lowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

PSPSB

PSCPSCB

PSPSB

PSCPSCB

0123456789

10

1 2 3 4 5 6 7 8 9

LW (c

m)

Time (weeks)

ns

lowastlowastlowast

lowastlowastlowast lowastlowastlowast lowastlowastlowast lowastlowastlowast lowastlowastlowastlowastlowast lowast

05

101520253035404550

1 2 3 4 5 6 7 8 9Time (weeks)

PSPSB

PSCPSCB

ns

LN (n

∘ middot)

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast

ns

0

20

40

60

80

100

120

140

LA (c

m2)

2 3 4 5 6 7 8 91Time (weeks)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowastlowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowast

Treatment Day Treat x day

LNF-value 635 909 834p-level 0000 0000 0000

LLF-value 1005 937 955p-levelF-valuep-levelF-valuep-levelF-valuep-level

0000 0000 0000

LW897 718 767

0000 0000 0000

LA1271 728 8760000 0000 0000

LP1437 1083 11790000 0000 0000

Figure 2 Morphological analysis The main leaf parameters were analyzed LN = leaf number LL = leaf length LW = leaf width LA = leafarea LP = leaf perimeter Data represent the mean (119899 = 6) plusmn standard error Mean values marked with asterisks are statistically different atlowastlowastlowast119901 le 00001 at lowastlowast119901 le 0005 and at lowast119901 le 001 Two-way ANOVA was applied to weigh the effects of day treatment and their interactionson plant growth parameters (119901 and 119865 level values are reported) PS = lettuce plants grown in unfertilized soil PSB = lettuce plants grown inunfertilized soil plus biochar PSC = lettuce plants grown in unfertilized soil plus compost and PSCB = lettuce plants grown in unfertilizedsoil plus compost and biochar


Table 2 Soil chemical properties Data represent the mean (119899 = 4) plusmn standard error Mean values marked with the same letter are notstatistically different One-way ANOVA was applied to weigh the effects of different treatments (119901 lt 005)

PS PSB PSC PSCBpH 69 plusmn 02d 80 plusmn 00a 75 plusmn 00c 77 plusmn 00b

Alkalinity ( CaCO3) 77 plusmn 04a 59 plusmn 05a 64 plusmn 03a 71 plusmn 04a

EC (dSm) 071 plusmn 00c 10 plusmn 00b 13 plusmn 01b 15 plusmn 00a

Moisture (gkg) 630 plusmn 16a 588 plusmn 03b 618 plusmn 09a 470 plusmn 21c

Ash () 938 plusmn 02a 900 plusmn 05b 908 plusmn 07b 860 plusmn 03c

Ntot (gkg) 08 plusmn 00c 12 plusmn 00b 19 plusmn 02a 22 plusmn 00a

Ptot (mgkg) 1999 plusmn 99c 3766 plusmn 523b 4556 plusmn 333ab 4710 plusmn 13a

Pav (mgkg) lt120 plusmn 00c lt120 plusmn 00c 249 plusmn 39b 583 plusmn 45a

Ctot (gkg) 128 plusmn 05c 591 plusmn 00a 291 plusmn 08b 659 plusmn 22a

CEC (cmolkg) 393 plusmn 00d 404 plusmn 00b 399 plusmn 00c 436 plusmn 00a

PS unfertilized soilPSB unfertilized soil plus biocharPSC compost fertilized soilPSCB compost fertilized soil plus biochar

while leaf length width area and perimeter were unchangedPlants grown in PSCB showed lower leaf length width areaand perimeter compared to PSC while leaf number wasunchanged Furthermore all leaf parameters were increasedin PSC compared to PS and also in PSCB compared to PSBalthough they were almost unchanged at the end of treatment(after 9 weeks)

Total plant dry weight considering leaf and root biomassincreased in PSB compared to PS on the contrary leafbiomass decreased in PSCB and root biomass was unchangedcompared to PSC andPSB (Figure 3) Chlorophyll content didnot show significant changes between treatments (data notshown)

The leaf water potential was more negative in plantsgrown in PS than those grown in other substrates followedby PSB and PSC and PSCB (Figure 4)

Stomatal conductance showed no significant differencesbetween control and treated plants (Figure 5) while transpi-ration rate was slightly increased in PSCB and unchanged inPSC and PSB compared to PS (Figure 5) Assimilation ratewas not altered by treatment with biochar (PSB) and biochar-compost (PSCB) In particular plants showed the highestassimilation rate and water use efficiency in PSC (Figure 5)

34 Cultivable Microorganisms The analysis of cultivablemicroorganisms showed that in PSB the cultivable aerobicbacteria actinomycetes and eumycetes decreased (119901 le005) compared to PS while they were unchanged in PSBCcompared to PSC (Table 3) Furthermore the abundanceof cultivable aerobic bacteria and eumycetes was higherin PSC than PS while actinomycetes were unchanged allcultivable microorganisms increased in PSCB compared toPSB (Table 3)

35 Soil Enzyme Activities Enzymatic profile analysisrevealed that all enzymatic activities were increased in PSCcompared to PS except lipase-esterase and esterase that wereunchanged Biochar treatment alone or in combination with

c

b

a

b

b

a

a

a

PS PSB PSC PSCB

0

1

2

3

4

5

Leav

es b

iom

ass (

g)

5

4

3

2

1

Root

s bio

mas

s (g)

Figure 3 Effects of biochar andor compost on leaf and root biomass(g of dry tissue weight) Data represent the mean (119899 = 6) plusmn standarderror Mean values marked with the same letter are not statisticallydifferent One-way ANOVA was applied to weigh the effects ofdifferent treatments (119901 le 005) PS = lettuce plants grown inunfertilized soil PSB = lettuce plants grown in unfertilized soilplus biochar PSC = lettuce plants grown in unfertilized soil pluscompost and PSCB = lettuce plants grown in unfertilized soil pluscompost and biochar

compost induced specific enzymatic variations In detail inPSB compared to PS the activities of alkaline phosphataseacid phosphatase chymotrypsin trypsin phosphohydrolaselipase-esterase and esterase were increased while lipase was


PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)

Figure 4 Leaf water potential at midday of plants grown in different substrates Values are means (119899 = 5) plusmn standard error significantdifferences between the means (at least 119901 le 005 according to ANOVA) appear with different letters PS = lettuce plants grown in unfertilizedsoil PSB = lettuce plants grown in unfertilized soil plus biochar PSC = lettuce plants grown in unfertilized soil plus compost and PSCB =lettuce plants grown in unfertilized soil plus compost and biochar

PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)

Figure 5 Transpiration rate stomatal conductance assimilation and water use efficiency (WUE) of plants grown in different soils Values aremeans (119899 = 5) plusmn standard error significant differences between the means (at least 119901 le 005 according to ANOVA) appear with differentletters PS = lettuce plants grown in unfertilized soil PSB = lettuce plants grown in unfertilized soil plus biochar PSC = lettuce plants grownin unfertilized soil plus compost and PSCB = lettuce plants grown in unfertilized soil plus compost and biochar

unchanged (Table 4) In PSBC compared to PSC alkalinephosphatase acid phosphatase lipase-esterase and esterasestrongly increased (119901 le 001) whereas chymotrypsin andtrypsin activities decreased (119901 le 005) and phosphohydrolaseand lipase activities were lost (Table 4) In PSCB comparedto PSB we recorded that alkaline phosphatase and acidphosphatase increased and trypsin phosphohydrolase and

esterase decreased while chymotrypsin lipase-esterase andlipase were unchanged (119901 le 005)

4 Discussion

Thestudy showed that both biochar amendment and compostaddition to a soil poor in nutrients induced a positive effect on


Table 3 Soil microbiological characteristics Values are expressed as log CFUg dry weight (DW) Data represent the mean (119899 = 3) plusmn standarderror Mean values marked with the same letter are not statistically different One-way ANOVA was applied to weigh the effects of differenttreatments (119901 lt 005) PS=unfertilized soil PSB=unfertilized soil plus biochar PSC=unfertilized soil plus compost andPSCB=unfertilizedsoil plus compost and biochar

PS PSB PSC PSCBCultivable aerobic bacteria 1097 plusmn 017a 788 plusmn 018c 884 plusmn 020b 835 plusmn 021b

Actinomycetes 867 plusmn 015a 52 plusmn 012c 64 plusmn 03b 61 plusmn 02b

Eumycetes 885 plusmn 012a 789 plusmn 008b 874 plusmn 1040a 852 plusmn 014a

Table 4 Soil enzymatic activities Soil enzymatic activities were determined by the API-ZYM system (bio-Merieux Italia) Results areexpressed as nanomolesg of dry weight of substrate the data have been corrected by the dilution factor PS = unfertilized soil PSB =unfertilized soil plus biochar PSC = unfertilized soil plus compost and PSCB = unfertilized soil plus compost and biochar

Enzyme PS PSB PSC PSCBAlkaline phosphatase 250 plusmn 25c 500 plusmn 25b 500 plusmn 50b 1000 plusmn 50a

Acid phosphatase 250 plusmn 25c 500 plusmn 50b 500 plusmn 25b 1000 plusmn 100a

Chymotrypsin 10 plusmn 5c 250 plusmn 25b 500 plusmn 25a 250 plusmn 25b

Trypsin 10 plusmn 5d 250 plusmn 50b 500 plusmn 50a 100 plusmn 25c

Phosphohydrolase 10 plusmn 5c 250 plusmn 25b 500 plusmn 50a 10 plusmn 5c

Lipase-esterase 10 plusmn 5b 500 plusmn 50a 10 plusmn 5b 500 plusmn 25a

Esterase 10 plusmn 5b 500 plusmn 25a 10 plusmn 5b 10 plusmn 5b

Lipase 10 plusmn 5b 10 plusmn 5b 250 plusmn 25a 10 plusmn 5b

lettuce plant growth and physiology and on soil chemical andmicrobiological characteristics however no positive synergicor summative effects exerted by compost and biochar incombination were observed

In detail the biochar alone induced a positive lettuce yieldresponse although transpiration stomatal conductance andassimilation rate did not show relevant variations Positiveyield responses to biochar addition have been reported for awide variety of crops For example it is reported that maizeyield increased by 98ndash150 as a result of manure biocharaddition [53] lettuce andArabidopsis plant biomass increasedby 111 after poplar wood chips biochar addition [54] andwheat grain yield increased by 18 with the use of oil malleebiochar [55]

A possible explanation is that the biochar increasing thepH CEC Ntot Ctot Ptot and water content could enhanceavailable nutrients for plants and consequently biomassaccumulation [22 56] In fact the increase in CEC valuecould be driven by the presence of cation exchange siteson the biochar surface [10 57] and as also reported inVaccari et al [58] this could contribute to retaining NH

4

+leading to improved N nutrition in biochar-amended soils[59ndash61] This would confirm a direct biochar role in thenutrient supply to plants [20 62] The increased pH inbiochar treated soil could also be indirectly related to growthstimulation in lettuce Indeed Beesley and Dickinson [63]hypothesized that soil alkalization caused by biochar additionmight positively influence earthworms as also observed inour study with a subsequent positive effect on dissolvedorganic carbon content The pH value has also been found toinfluence the soil microbial population and enzymatic activ-ities indeed a high pH might enhance bacteria abundance

whereas it did not change fungi total biomass or dramati-cally reduce their growth [64 65] The activity of alkalinephosphatase aminopeptidase and N-acetylglucosaminidaseenzymes has also been reported to increase after biocharapplications [66 67] In accordance with this evidence ourresults showed that the biochar alone decreased cultivablemicroorganisms abundance while it enhanced the activityof enzymes involved in phosphorus nitrogen and carboncycling (alkaline phosphatase acid phosphatase phosphohy-drolase lipase-esterase esterase chymotrypsin and trypsin)These results could indicate that although the bacteriaabundance could be reduced by biochar soil alkalizationthe microbial communities related to nitrogen phosphorusand carbon cycling could be stimulated by biochar-inducedincreasing of soil Ptot Ntot and Ctot availability [68 69]

Nevertheless the compost alone amendment showed thebest clear and positive effects on plant growth and yield andon soil chemical characteristics Indeed according to datareported in the literature [70 71] in compost amended soillettuce plants showed the maximum total biomass accumu-lation assimilation rate and water use efficiency probablydue to the high soil nutrients availability (soil Ctot Ntot Ptotand Pav content was increased) This high soil nutrient statuscould also have enhanced the activity of enzymes involvedin phosphorus and nitrogen cycling (phosphohydrolase chy-motrypsin and trypsin) which increased compared to thosein the unamended soils on the other hand the slight pHincrease could be responsible for the decrease of cultivablebacteria

No synergic or positive effects exerted by compost andbiochar combination were observed here compared to thecompost alone treatment Indeed we showed that lettuce


growth changes were negligible combining compost andbiochar amendment although as shown above the amountof compost applied and the nutrients supplied were ade-quate to produce the highest plant benefits in the compostalone treatment Furthermore compared to the additionof compost alone the compost and biochar combinationdid not improve soil chemical characteristics except for anincrease in Ctot and Pav content These increases could berelated to biochar capacity to enhance C accumulation andsequestration and to retain and exchange phosphate ions byits positively charged surface sites [59 60] Additionally incompost and biochar-amended soil microorganism abun-dance was unchanged while the activity of enzymes involvedin N and P mineralization (chymotrypsin trypsin andphosphohydrolase) was reduced or completely lost comparedto those in the compost alone treatment

It is reported that biochar can have significant effectson microbially mediated transformation of nutrients by itssurface interaction with substrate and soil microbial enzymes[72 73] or by inducing soil alkalization [74] Indeed wehypothesized that soil microbial abundance and activitieswere shaped by nutrient availability and pH which inturn could be balanced by biochar-compost combinationHowever the biochar benefits could be amplified overtime through surface oxidation and bioactivation with soilmicrobes and fungi [75 76] In addition given that thebeneficial effects of biochar were found to increase more insandy than in loamy substrates [25] we hypothesized thatin PSCB the high nutrient status due to the compost couldhave masked biochar effects [77]

In summary our short-term potting experiment clearlydemonstrated that compost addition provided the best solu-tion regarding soil quality and fertility which were alsoreflected in best plant growth and biomass yield

Furthermore taking into account that the soil used in thisstudy had low nutrient status suboptimal for plant growthwithout additions of organic andor inorganic amendmentsthese results demonstrate that the application of biocharalone could also be effectively used to enhance soil fertilityand plant growth and biomass yield This may have impor-tant implications for sustainable low-input agriculture witheconomic and environmental benefits for both marginal andproductive cropland

Nevertheless unexpectedly combined application ofbiochar and compost did not outperform compost amend-ment in terms of biomass yield and soil fertility Howeverit may enhance and sustain soil biophysical and chemicalcharacteristics over time given that most of compost willdisappear through mineralization within 5 years after appli-cation whereas most of the biochar will stay in the soil fordecades [20 78]

Further long-term and large-scale field experiments arerequired to analyze differences over time and in particularto quantify the amount of recalcitrant carbon supplied andsequestered in the soil by both biochar alone and thecombination of biochar and compost Their benefits andeffects in terms of improving and sustaining soil fertility cropproductivity and economic returns to users should be alsoevaluated over time

Conflicts of Interest

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

Authorsrsquo Contributions

Gabriella Stefania Scippa coordinated the project GabriellaStefania Scippa Dalila Trupiano Claudia Cocozza andRoberto Tognetti conceived and designed the experimentsDalila Trupiano Carla Amendola Claudia CocozzaFrancesca Fantasma Silvia Baronti Sara Di Lonardo andGiuseppe Lustrato performed the experiments DalilaTrupiano Carla Amendola Claudia Cocozza Silvia BarontiSara Di Lonardo and Giuseppe Lustrato analyzed dataGabriella Stefania Scippa contributed reagentsmaterialsanalysis tools Dalila Trupiano wrote themanuscript ClaudiaCocozza Roberto Tognetti Silvia Baronti and FrancescoPrimo Vaccari revised the manuscript All authors approvedthe manuscript

Acknowledgments

The authors thank Dr Luisa Andrenelli and Dr AdrianoBaglio (University of Florence) Italian Biochar Association(ICHAR httpwwwicharorg) and Federica Oliva (Univer-sity of Molise) for their technical support during labora-tory measurements Research was supported by grants fromMolise Region (PSR Molise 20072013-Misura 124) throughthe ProSEEAA Project (CUP D95F14000030007) and itcontributes to the EuroCHAR Project (FP7-ENV-2010 ID-265179)

References

[1] J A Foley R DeFries G P Asner et al ldquoGlobal consequencesof land userdquo Science vol 309 no 5734 pp 570ndash574 2005

[2] E Liu C Yan X Mei et al ldquoLong-term effect of chemicalfertilizer straw and manure on soil chemical and biologicalproperties in northwest Chinardquo Geoderma vol 158 no 3-4 pp173ndash180 2010

[3] B Vanlauwe A Bationo J Chianu et al ldquoIntegrated soilfertility management operational definition and consequencesfor implementation and disseminationrdquoOutlook on Agriculturevol 39 no 1 pp 17ndash24 2010

[4] J C Aciego Pietri and P C Brookes ldquoRelationships between soilpH and microbial properties in a UK arable soilrdquo Soil Biologyand Biochemistry vol 40 no 7 pp 1856ndash1861 2008

[5] S Sohi E Lopez-Capel E Krull and R Bol ldquoBiochar climatechange and soil a review to guide future researchrdquo CSIRO Landand Water Science Report 0509 2009

[6] C J Ennis A G Evans M Islam T K Ralebitso-Senior and ESenior ldquoBiochar carbon sequestration land remediation andimpacts on soil microbiologyrdquo Critical Reviews in Environmen-tal Science and Technology vol 42 no 22 pp 2311ndash2364 2012

[7] S Malghani G Gleixner and S E Trumbore ldquoChars producedby slow pyrolysis and hydrothermal carbonization vary in car-bon sequestration potential and greenhouse gases emissionsrdquoSoil Biology and Biochemistry vol 62 pp 137ndash146 2013


[8] C E Stewart J Zheng J Botte and M F Cotrufo ldquoCo-generated fast pyrolysis biochar mitigates green-house gasemissions and increases carbon sequestration in temperatesoilsrdquo GCB Bioenergy vol 5 no 2 pp 153ndash164 2013

[9] A Mukherjee and R Lal ldquoBiochar impacts on soil physicalproperties and greenhouse gas emissionsrdquoAgronomy vol 3 pp313ndash339 2013

[10] S P Sohi E Krull E Lopez-Capel and R Bol ldquoA review ofbiochar and its use and function in soilrdquoAdvances in Agronomyvol 105 no 1 pp 47ndash82 2010

[11] LA Biederman andW StanleyHarpole ldquoBiochar and its effectson plant productivity and nutrient cycling a meta-analysisrdquoGCB Bioenergy vol 5 no 2 pp 202ndash214 2013

[12] S Jeffery F G A Verheijen M van der Velde and A C BastosldquoA quantitative review of the effects of biochar application tosoils on crop productivity using meta-analysisrdquo AgricultureEcosystems and Environment vol 144 no 1 pp 175ndash187 2011

[13] N M Jaafar P L Clode and L K Abbott ldquoMicroscopyobservations of habitable space in biochar for colonization byfungal hyphae from soilrdquo Journal of Integrative Agriculture vol13 no 3 pp 483ndash490 2014

[14] R S Quilliam H C Glanville S C Wade and D L JonesldquoLife in the lsquocharospherersquomdashdoes biochar in agricultural soilprovide a significant habitat for microorganismsrdquo Soil Biologyand Biochemistry vol 65 pp 287ndash293 2013

[15] J Lehmann M C Rillig J Thies C A Masiello W CHockaday and D Crowley ldquoBiochar effects on soil biotamdashareviewrdquo Soil Biology and Biochemistry vol 43 no 9 pp 1812ndash1836 2011

[16] K Crombie O Masek A Cross and S Sohi ldquoBiocharmdashsynergies and trade-offs between soil enhancing properties andC sequestration potentialrdquoGCB Bioenergy vol 7 no 5 pp 1161ndash1175 2015

[17] J Thies and M C Rillig ldquoCharacteristics of biochar biologicalpropertiesrdquo in Biochar for Environmental Management Scienceand Technology J Lehmann and S Josep Eds EarthscanLondon UK 2009

[18] K A Spokas K B Cantrell J M Novak et al ldquoBiochar a syn-thesis of its agronomic impact beyond carbon sequestrationrdquoJournal of Environmental Quality vol 41 no 4 pp 973ndash9892012

[19] R D Lentz and J A Ippolito ldquoBiochar and manure affectcalcareous soil and corn silage nutrient concentrations anduptakerdquo Journal of EnvironmentalQuality vol 41 pp 1033ndash10432012

[20] B Glaser J Lehmann andW Zech ldquoAmeliorating physical andchemical properties of highly weathered soils in the tropics withcharcoalmdasha reviewrdquo Biology and Fertility of Soils vol 35 no 4pp 219ndash230 2002

[21] B Glaser and J J Birk ldquoState of the scientific knowledge onproperties and genesis ofAnthropogenicDarkEarths inCentralAmazonia (terra preta de ındio)rdquo Geochimica et CosmochimicaActa vol 82 pp 39ndash51 2012

[22] R Scotti G Bonanomi R Scelza A Zoina and M A RaoldquoOrganic amendments as sustainable tool to recovery fertility inintensive agricultural systemsrdquo Journal of Soil Science and PlantNutrition vol 15 no 2 pp 333ndash352 2015

[23] K S Khan and R G Joergensen ldquoCompost and phosphorusamendments for stimulating microorganisms and growth ofryegrass in a Ferralsol and a Luvisolrdquo Journal of Plant Nutritionand Soil Science vol 175 no 1 pp 108ndash114 2012

[24] D Fischer and B Glaser ldquoSynergisms between compost andbiochar for sustainable soil ameliorationrdquo in Management ofOrganic Waste S Kumar and A Bharti Eds pp 167ndash198InTech 2012

[25] H Schulz and B Glaser ldquoEffects of biochar compared to organicand inorganic fertilizers on soil quality and plant growth ina greenhouse experimentrdquo Journal of Plant Nutrition and SoilScience vol 175 no 3 pp 410ndash422 2012

[26] J Liu H Schulz S Brandl H Miehtke B Huwe and B GlaserldquoShort-term effect of biochar and compost on soil fertility andwater status of a Dystric Cambisol in NE Germany under fieldconditionsrdquo Journal of Plant Nutrition and Soil Science vol 175no 5 pp 698ndash707 2012

[27] G Agegnehu M I Bird P N Nelson and A M Bass ldquoTheameliorating effects of biochar and compost on soil quality andplant growth on a Ferralsolrdquo Soil Research vol 53 no 1 pp 1ndash122015

[28] H P Schmidt C Kammann C Niggli M W H EvangelouK A Mackie and S Abiven ldquoBiochar and biochar-compost assoil amendments to a vineyard soil influences on plant growthnutrient uptake plant health and grape qualityrdquo AgricultureEcosystems amp Environment vol 191 pp 117ndash123 2014

[29] M P Bernal J A Alburquerque and R Moral ldquoCompostingof animal manures and chemical criteria for compost maturityassessment A reviewrdquo Bioresource Technology vol 100 no 22pp 5444ndash5453 2009

[30] G Alfano G Lustrato G Lima D Vitullo and G RanallildquoCharacterization of composted olive mill wastes to predictpotential plant disease suppressivenessrdquo Biological Control vol58 no 3 pp 199ndash207 2011

[31] C Amendola A Montagnoli M Terzaghi et al ldquoShort-term effects of biochar on grapevine fine root dynamics andarbuscular mycorrhizae productionrdquo Agriculture Ecosystems ampEnvironment vol 239 pp 236ndash245 2017

[32] D Vitullo R Altieri A Esposito et al ldquoSuppressive biomassesand antagonist bacteria for an eco-compatible control of Ver-ticillium dahliae on nursery-grown olive plantsrdquo InternationalJournal of Environmental Science and Technology vol 10 no 2pp 209ndash220 2013

[33] ISO ldquoSoil qualitymdashavoidance test for determining the qualityof soils and effects of chemicals on behaviour - part 1 test withearthworms (Eisenia fetida and Eisenia andrei)rdquo ISO 17512-12008

[34] USDA United States Department of Agriculture Natu-ral Resources Conservation Service National Soil SurveyHandbook 2005 httpwwwnrcsusdagovwpsportalnrcsdetailnationalhomecid=nrcs142p2_054241

[35] S Carter S Shackley S Sohi T B Suy and S Haefele ldquoTheimpact of biochar application on soil properties and plantgrowth of pot grown lettuce (Lactuca sativa) and cabbage(Brassica chinensis)rdquo Agronomy vol 3 no 2 pp 404ndash418 2013

[36] H Sokchea K Borin and T R Preston ldquoEffect of biochar fromrice husks (combusted in a downdraft gasifier or a paddy ricedryer) on production of rice fertilized with biodigester effluentor ureardquo Livestock Research for Rural Development vol 25 no1 2013

[37] A Fabrizio F Tambone and P Genevini ldquoEffect of compostapplication rate on carbon degradation and retention in soilsrdquoWaste Management vol 29 no 1 pp 174ndash179 2009

[38] M Reis L Coelho J Beltrao I Domingos and M MouraldquoComparative response of lettuce (Lactuca sativa) to inorganic


and organic compost fertilizationrdquo in Recent Advances inEnergy Environment Economics and Technological Innovationpp 61ndash68 2008

[39] J Lehmann J Gaunt and M Rondon ldquoBio-char sequestrationin terrestrial ecosystemsmdasha reviewrdquoMitigation and AdaptationStrategies for Global Change vol 11 no 2 pp 403ndash427 2006

[40] C A Black Methods of Soil Analysis Part I Physical and Min-eralogical Properties American Society of Agronomy MadisonWis USA 1965

[41] F R Higginson and G E Rayment Australian LaboratoryHandbook of Soil and Water Chemical Methods Inkata Press1992

[42] Y P Kalra and Soil amp Plant Analysis Council Handbookon Reference Methods for Soil Analysis Soil amp Plant AnalysisCouncil 1992

[43] ASTM ldquoStandard test methods for moisture ash and organicmatter of peat and other organic soilsrdquo ASTMD2974-00 ASTMInternational West Conshohocken Pa USA 2000

[44] A Mehlich ldquoUse of triethanolamine acetate-barium hydroxidebuffer for the determination of some base exchange propertiesand lime requirement of soilrdquo Soil Science Society of AmericaProceedings vol 29 pp 374ndash378 1938

[45] C F H Liao ldquoDevardarsquos alloy method for total nitrogendeterminationrdquo Soil Science Society of America Journal vol 45no 5 pp 852ndash855 1981

[46] R A Bowman ldquoA rapid method to determine total phosphorusin soilsrdquo Soil Science Society of America Journal vol 52 no 5pp 1301ndash1304 1988

[47] S R Olsen C V Cole F S Watanabe and L A DeanEstimation of available phosphorus in soils by extraction withsodium bicarbonate Circular 939 USDA Washington DCUSA 1954

[48] J B A Dumas ldquoProcedes de lrsquoanalyse organiquerdquo Annales deChimie et de Physique vol 247 pp 198ndash213 1831

[49] R Moran and D Porath ldquoChlorophyll determination in intacttissues using NN-dimethylformamiderdquo Plant Physiology vol65 no 3 pp 478ndash479 1980

[50] W P Inskeep and P R Bloom ldquoExtinction coefficients ofchlorophyll a and b in nn-dimethylformamide and 80 ace-tonerdquo Plant Physiology vol 77 no 2 pp 483ndash485 1985

[51] C Viti A Mini G Ranalli G Lustrato and L GiovannettildquoResponse of microbial communities to different doses ofchromate in soil microcosmsrdquo Applied Soil Ecology vol 34 no2-3 pp 125ndash139 2006

[52] S M Tiquia ldquoEvolution of extracellular enzyme activitiesduring manure compostingrdquo Journal of Applied Microbiologyvol 92 no 4 pp 764ndash775 2002

[53] K C Uzoma M Inoue H Andry H Fujimaki A Zahoor andE Nishihara ldquoEffect of cow manure biochar on maize produc-tivity under sandy soil conditionrdquo Soil Use and Managementvol 27 no 2 pp 205ndash212 2011

[54] MViger RDHancock FMiglietta andG Taylor ldquoMore plantgrowth but less plant defence First global gene expression datafor plants grown in soil amended with biocharrdquoGCB Bioenergyvol 7 no 4 pp 658ndash672 2015

[55] Z M Solaiman P Blackwell L K Abbott and P Storer ldquoDirectand residual effect of biochar application on mycorrhizal rootcolonisation growth and nutrition of wheatrdquoAustralian Journalof Soil Research vol 48 no 6-7 pp 546ndash554 2010

[56] M RosM T Hernandez andC Garcıa ldquoSoil microbial activityafter restoration of a semiarid soil by organic amendmentsrdquo SoilBiology and Biochemistry vol 35 no 3 pp 463ndash469 2003

[57] D L Jones J Rousk G Edwards-Jones T H DeLuca and DV Murphy ldquoBiochar-mediated changes in soil quality and plantgrowth in a three year field trialrdquo Soil Biology and Biochemistryvol 45 pp 113ndash124 2012

[58] F P Vaccari A Maienza F Miglietta et al ldquoBiochar stimulatesplant growth but not fruit yield of processing tomato in a fertilesoilrdquoAgriculture Ecosystems and Environment vol 207 pp 163ndash170 2015

[59] T H De Luca M D MacKenzie and M J Gundale ldquoBiochareffects on soil nutrient transformationsrdquo in Biochar for Environ-mentalManagement Science and Technology J Lehmann and SJoseph Eds pp 251ndash270 Earthscan Publications London UK2009

[60] J Major C Steiner A Downie and J Lehmann ldquoBiochareffects on nutrient leachingrdquo in Biochar for EnvironmentalManagement Science andTechnology J Lehmann and S JosephEds pp 271ndash287 Earthscan London UK 2009

[61] C C Hollister J J Bisogni and J Lehmann ldquoAmmoniumnitrate and phosphate sorption to and solute leaching frombiochars prepared from corn stover (Zeamays L) and oakwood(Quercus spp)rdquo Journal of Environmental Quality vol 42 no 1pp 137ndash144 2013

[62] T J Clough and L M Condron ldquoBiochar and the nitrogencycle introductionrdquo Journal of Environmental Quality vol 39no 4 pp 1218ndash1223 2010

[63] L Beesley and N Dickinson ldquoCarbon and trace elementfluxes in the pore water of an urban soil following greenwastecompost woody and biochar amendments inoculated with theearthworm Lumbricus terrestrisrdquo Soil Biology and Biochemistryvol 43 no 1 pp 188ndash196 2011

[64] J Prommer W Wanek F Hofhansl et al ldquoBiochar deceleratessoil organic nitrogen cycling but stimulates soil nitrification ina temperate arable field trialrdquo PLoS ONE vol 9 no 1 Article IDe86388 2014

[65] C R Anderson L M Condron T J Clough et al ldquoBiocharinduced soil microbial community change implications forbiogeochemical cycling of carbon nitrogen and phosphorusrdquoPedobiologia vol 54 no 5-6 pp 309ndash320 2011

[66] J Rousk P C Brookes and E Baath ldquoContrasting soil pHeffects on fungal and bacterial growth suggest functional redun-dancy in carbon mineralizationrdquo Applied and EnvironmentalMicrobiology vol 75 no 6 pp 1589ndash1596 2009

[67] J Rousk P C Brookes and E Baath ldquoInvestigating themechanisms for the opposing pH relationships of fungal andbacterial growth in soilrdquo Soil Biology and Biochemistry vol 42no 6 pp 926ndash934 2010

[68] V L Bailey S J Fansler J L Smith and H Bolton Jr ldquoRecon-ciling apparent variability in effects of biochar amendment onsoil enzyme activities by assay optimizationrdquo Soil Biology andBiochemistry vol 43 no 2 pp 296ndash301 2011

[69] H Jin Characterization of microbial life colonizing biochar andbiochar amended soils [PhD thesis] Cornell University IthacaNY USA 2010

[70] F Amlinger S Peyr J Geszti P Dreher W Karlheinz and SNortcliff Beneficial Effects of Compost Application on Fertilityand Productivity of Soils Federal Ministry for Agricultural andForestry Environment and Water Management Lebensminis-terium Vienna Austria 2007

[71] M Diacono and F Montemurro ldquoLong-term effects of organicamendments on soil fertilityrdquo Journal of Sustainable Agriculturevol 2 pp 761ndash786 2011


[72] V L Bailey S J Fansler J L Smith andH Bolton ldquoReconcilingapparent variability in effects of biochar amendment on soilenzyme activities by assay optimizationrdquo Soil Biology andBiochemistry vol 43 no 2 pp 296ndash301 2011

[73] C Lammirato A Miltner and M Kaestner ldquoEffects of woodchar and activated carbon on the hydrolysis of cellobiose by 120573-glucosidase from Aspergillus nigerrdquo Soil Biology and Biochem-istry vol 43 no 9 pp 1936ndash1942 2011

[74] Y Yao B Gao M Inyang et al ldquoBiochar derived fromanaerobically digested sugar beet tailings characterization andphosphate removal potentialrdquo Bioresource Technology vol 102no 10 pp 6273ndash6278 2011

[75] H-J Xu X-H Wang H Li H-Y Yao J-Q Su and Y-GZhu ldquoBiochar impacts soil microbial community compositionand nitrogen cycling in an acidic soil planted with raperdquoEnvironmental Science and Technology vol 48 no 16 pp 9391ndash9399 2014

[76] W-C Ding X-L Zeng Y-F Wang Y Du and Q-X ZhuldquoCharacteristics and performances of biofilm carrier preparedfrom agro-based biocharrdquo China Environmental Science vol 31no 9 pp 1451ndash1455 2011

[77] B T Nguyen J Lehmann W C Hockaday S Joseph and C AMasiello ldquoTemperature sensitivity of black carbon decomposi-tion and oxidationrdquo Environmental Science and Technology vol44 no 9 pp 3324ndash3331 2010

[78] Y Kuzyakov I Subbotina H Chen I Bogomolova and XXu ldquoBlack carbon decomposition and incorporation into soilmicrobial biomass estimated by 14C labelingrdquo Soil Biology andBiochemistry vol 41 no 2 pp 210ndash219 2009

Submit your manuscripts athttpswwwhindawicom

Nutrition and Metabolism

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Food ScienceInternational Journal of

Agronomy


International Journal of



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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

AgricultureAdvances in


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GenomicsInternational Journal of


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Evolutionary BiologyInternational Journal of



Table 1 Biochar and compost characteristics The complete biochar and compost characterization and related methods are detailed inAmendola et al [31] and Alfano et al [30] respectively All concentrations refer to dry matter and represent the means of three replicates plusmnstandard error

Biochar CompostpH 97 plusmn 01 75 plusmn 01Alkalinity ( CaCO

3) 182 plusmn 07 65 plusmn 04

EC (dSm) 75 plusmn 04 49 plusmn 03Moisture (gkg) 624 plusmn 13 34 plusmn 09CEC (cmolkg) 213 plusmn 02 210 plusmn 02Ptot (gkg) 122 plusmn 30 55 plusmn 06Ntot (gkg) 91 plusmn 02 120 plusmn 40Ctot (gkg) 7781 plusmn 00 3372 plusmn 03CN 1255 281Cultivable aerobic bacteria (log CFUg) Absent 76 plusmn 03Eumycetes (log CFUg) Absent 49 plusmn 01Actinomycetes (log CFUg) Absent 518 plusmn 02Coliform bacteria (log CFUg) Absent AbsentE coli (log CFUg) Absent AbsentSalmonellae spp (log CFUg) Absent Absent

The beneficial effects of biochar on plant productivity andsoil microbial population are related to the improvement ofspecific surface area cation exchange capacity bulk densitypH water and nutrients within the soil matrix [17] Besidethe generally positive plant growth responses to biocharamendment especially in acidic coarse texture soil negligibleor negative effects also occur due to types of feedstockand pyrolysis process biochar application rate plant speciesand soil characteristics [18 19] Furthermore in most casesbiochar does not provide high amounts of nutrients [20 21]

Some recent studies have indicated that combined appli-cations of biochar with organic or inorganic fertilizers couldlead to enhanced soil physical chemical and biologicalproperties as well as plant growth In particular several com-posted materials represent a sustainable source of availablenutrients that could enhance plant growth ameliorating soilphysicochemical characteristics and microbiological proper-ties [22ndash26] Liu et al [26] showed that the combined applica-tion of compost and biochar had a positive synergistic effecton soil nutrient contents and water-holding capacity underfield conditions In addition the combination of biochar withcompost has proved to be suitable allowing the reduction offertilizer inputs stabilizing the soil structure and improvingits nutrient content and water retention capacity [27 28]Again these studies underline that compost and biocharcombination could enhance compost properties leading toa higher added value and a much better carbon sequestrationpotential due to the long-term stability of biochar [24 25]

However the literature shows that compost effects as alsoreported above for biochar can differ on soil biophysical-chemical properties and plant growth and yield on the basisof feedstock types methods of producing and application[29] The objectives of this study were thus to determine theeffect of biochar application alone obtained from orchardpruning biomass by slow pyrolysis (550∘C) or combinedwith compost obtained from olive mill residues on (i) plant

growth physiology and yield (ii) soil chemical character-istics and (iii) soil microbiological abundance and enzymeactivities For this purpose a short-term potting experimentwas performed using Lactuca sativa L as reference plantsand a soil poor in nutrients as growing substrate to testthe following hypotheses biochar addition together withcompost improves (1) soil chemical and (2) microbiologicalproperties and enhances (3) plant growth and physiologymore than compost and biochar alone

2 Materials and Methods

21 Biochar Compost and Toxicity Test The biochar usedwas a commercial charcoal (provided by Romagna Carbonesnc Italy) obtained fromorchard pruning biomass througha slow pyrolysis process at a temperature of 500∘C in atransportable ring kiln 22m in diameter that holds around2 t of feedstock

An olive waste compost was used prepared in a specificexperimental composting process following Alfano et al[30] Briefly compost was prepared mixing humid olivehusks from a two-phase extraction plant with olive leaves(8ww) one-year-old humid composted husks (25ww)were then added to this mixture Biochar and compost char-acteristics are summarized in Table 1 and analytical methodsare provided in Amendola et al [31] and Alfano et al [30]

Biochar and compost phytotoxicity was assessed throughthe germination index (GI) of cress plants (Lepidiumsativum L) [26] Three different solutions were used toevaluate the biochar and compost toxicity on seed ger-mination sterile deionized water as control solution andsolutions containing 50 and 75 extract of biochar orcompost Solutions were added to Petri dishes containing10 sterile seeds of L sativum Germination percentage andplant root length were recorded after incubation for 42 hat 27∘C in the dark (according to Vitullo et al [32]) Seeds



119904and 119871



119888








2O and 001M CaCl

2




minus-N and NO2


3solution at





1198606645minus 279

119860647 Chl b = 2070

119860647minus 462

1198606645


Chl = 1790119860647

+ 8081198606645





3 Results


PS0

5

10

15

20

25

30

35

40

Eart

hwor

ms n

umbe

r

lowast

SamplesPSB








PSPSB

PSCPSCB

0

5

10

15

20

25

LL (c

m)

1 2 3 4 5 6 7 8 9Time (weeks)

ns




lowastlowast

PSPSB

PSCPSCB

1 2 3 4 5 6 7 8 9Time (weeks)

0

10

20

30

40

50

60

LP (c

m)

ns


lowastlowastlowast

lowastlowastlowast

PSPSB

PSCPSCB

PSPSB

PSCPSCB

0123456789

10

1 2 3 4 5 6 7 8 9

LW (c

m)

Time (weeks)

ns

lowastlowastlowast


05

101520253035404550

1 2 3 4 5 6 7 8 9Time (weeks)

PSPSB

PSCPSCB

ns

LN (n

∘ middot)

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast

ns

0

20

40

60

80

100

120

140

LA (c

m2)

2 3 4 5 6 7 8 91Time (weeks)

lowastlowastlowast

lowastlowastlowast




LNF-value 635 909 834p-level 0000 0000 0000


0000 0000 0000

LW897 718 767

0000 0000 0000

LA1271 728 8760000 0000 0000

LP1437 1083 11790000 0000 0000





















c

b

a

b

b

a

a

a

PS PSB PSC PSCB

0

1

2

3

4

5

Leav

es b

iom

ass (

g)

5

4

3

2

1

Root

s bio

mas

s (g)




PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)


PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)




4 Discussion



















4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology



























119904and 119871



119888








2O and 001M CaCl

2




minus-N and NO2


3solution at





1198606645minus 279

119860647 Chl b = 2070

119860647minus 462

1198606645


Chl = 1790119860647

+ 8081198606645





3 Results


PS0

5

10

15

20

25

30

35

40

Eart

hwor

ms n

umbe

r

lowast

SamplesPSB








PSPSB

PSCPSCB

0

5

10

15

20

25

LL (c

m)

1 2 3 4 5 6 7 8 9Time (weeks)

ns




lowastlowast

PSPSB

PSCPSCB

1 2 3 4 5 6 7 8 9Time (weeks)

0

10

20

30

40

50

60

LP (c

m)

ns


lowastlowastlowast

lowastlowastlowast

PSPSB

PSCPSCB

PSPSB

PSCPSCB

0123456789

10

1 2 3 4 5 6 7 8 9

LW (c

m)

Time (weeks)

ns

lowastlowastlowast


05

101520253035404550

1 2 3 4 5 6 7 8 9Time (weeks)

PSPSB

PSCPSCB

ns

LN (n

∘ middot)

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast

ns

0

20

40

60

80

100

120

140

LA (c

m2)

2 3 4 5 6 7 8 91Time (weeks)

lowastlowastlowast

lowastlowastlowast




LNF-value 635 909 834p-level 0000 0000 0000


0000 0000 0000

LW897 718 767

0000 0000 0000

LA1271 728 8760000 0000 0000

LP1437 1083 11790000 0000 0000





















c

b

a

b

b

a

a

a

PS PSB PSC PSCB

0

1

2

3

4

5

Leav

es b

iom

ass (

g)

5

4

3

2

1

Root

s bio

mas

s (g)




PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)


PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)




4 Discussion



















4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology


























Chl = 1790119860647

+ 8081198606645





3 Results


PS0

5

10

15

20

25

30

35

40

Eart

hwor

ms n

umbe

r

lowast

SamplesPSB








PSPSB

PSCPSCB

0

5

10

15

20

25

LL (c

m)

1 2 3 4 5 6 7 8 9Time (weeks)

ns




lowastlowast

PSPSB

PSCPSCB

1 2 3 4 5 6 7 8 9Time (weeks)

0

10

20

30

40

50

60

LP (c

m)

ns


lowastlowastlowast

lowastlowastlowast

PSPSB

PSCPSCB

PSPSB

PSCPSCB

0123456789

10

1 2 3 4 5 6 7 8 9

LW (c

m)

Time (weeks)

ns

lowastlowastlowast


05

101520253035404550

1 2 3 4 5 6 7 8 9Time (weeks)

PSPSB

PSCPSCB

ns

LN (n

∘ middot)

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast

ns

0

20

40

60

80

100

120

140

LA (c

m2)

2 3 4 5 6 7 8 91Time (weeks)

lowastlowastlowast

lowastlowastlowast




LNF-value 635 909 834p-level 0000 0000 0000


0000 0000 0000

LW897 718 767

0000 0000 0000

LA1271 728 8760000 0000 0000

LP1437 1083 11790000 0000 0000





















c

b

a

b

b

a

a

a

PS PSB PSC PSCB

0

1

2

3

4

5

Leav

es b

iom

ass (

g)

5

4

3

2

1

Root

s bio

mas

s (g)




PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)


PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)




4 Discussion



















4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology


























PSPSB

PSCPSCB

0

5

10

15

20

25

LL (c

m)

1 2 3 4 5 6 7 8 9Time (weeks)

ns




lowastlowast

PSPSB

PSCPSCB

1 2 3 4 5 6 7 8 9Time (weeks)

0

10

20

30

40

50

60

LP (c

m)

ns


lowastlowastlowast

lowastlowastlowast

PSPSB

PSCPSCB

PSPSB

PSCPSCB

0123456789

10

1 2 3 4 5 6 7 8 9

LW (c

m)

Time (weeks)

ns

lowastlowastlowast


05

101520253035404550

1 2 3 4 5 6 7 8 9Time (weeks)

PSPSB

PSCPSCB

ns

LN (n

∘ middot)

lowastlowastlowast



lowastlowastlowast

lowastlowastlowast

ns

0

20

40

60

80

100

120

140

LA (c

m2)

2 3 4 5 6 7 8 91Time (weeks)

lowastlowastlowast

lowastlowastlowast




LNF-value 635 909 834p-level 0000 0000 0000


0000 0000 0000

LW897 718 767

0000 0000 0000

LA1271 728 8760000 0000 0000

LP1437 1083 11790000 0000 0000





















c

b

a

b

b

a

a

a

PS PSB PSC PSCB

0

1

2

3

4

5

Leav

es b

iom

ass (

g)

5

4

3

2

1

Root

s bio

mas

s (g)




PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)


PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)




4 Discussion



















4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology












































c

b

a

b

b

a

a

a

PS PSB PSC PSCB

0

1

2

3

4

5

Leav

es b

iom

ass (

g)

5

4

3

2

1

Root

s bio

mas

s (g)




PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)


PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)




4 Discussion



















4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology


























PS PSB PSC PSCB

c

b

a a

minus10

minus08

minus06

minus04

minus02

00

Leaf

wat

er p

oten

tial (

MPa

)


PS PSB PSC PSCB

b

b

b

a

Tran

spira

tion

rate

00

05

10

15

20

25

30

35

40

(mm

olm

minus2

secminus

1)

PS PSB PSC PSCB

c

b

a

b

Ass

imila

tion

0123456789

10

(휇m

ol C

O2m

minus2

secminus

1)

PS PSB PSC PSCB

b

b

a

b

WU

E

0

1

2

3

4

5

(휇m

ol C

O2m

mol

H2O

)

PS PSB PSC PSCB

aa

aa

Stom

atal

cond

ucta

nce

0

50

100

150

200

250

300

(mm

olm

minus2

secminus

1)




4 Discussion



















4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology










































4
















Acknowledgments


References





















































































Journal of




Agronomy





Microbiology




































Acknowledgments


References





















































































Journal of




Agronomy





Microbiology






































































































Journal of




Agronomy





Microbiology

























The Effects of Biochar and Its Combination with Compost on...

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Transcript of The Effects of Biochar and Its Combination with Compost on...