Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system

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Blanchet, G., Gavazov, K., Bragazza, L., Sinaj, S. (2016)

Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system.

Agriculture, Ecosystems & Environment, 230: 116-126 http://dx.doi.org/10.1016/j.agee.2016.05.032

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Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system

GuillaumeBlanchet^a,KonstantinGavazov^b,LucaBragazza^c,d,e,Sokrat Sinaj^a,*

aAgroscope,InstituteofCropSciencesIPV,RoutedeDuillier50,P.O.Box1012,1260Nyon,Switzerland

bClimateImpactsResearchCentre,DepartmentofEcologyandEnvironmentalScience,UmeåUniversity,98107Abisko,Sweden

cLaboratoryofEcologicalSystems,SchoolofArchitecture,CivilandEnvironmentalEngineering,ÉcolePolytechniqueFédéraledeLausanne,1015Lausanne, Switzerland

dSwissFederalInstituteforForest,SnowandLandscapeResearch,SiteLausanne,1015Lausanne,Switzerland

eDepartmentofLifeScienceandBiotechnologies,UniversityofFerrara,CorsoErcoleId’Este32,44121Ferrara,Italy

ARTICLE INFO

Articlehistory:

Received19April2016

Receivedinrevisedform20May2016 Accepted27May2016

Availableonlinexxx

Keywords:

Cattlefarmyardmanure Cropresidues Nfertilization Microbialcommunity Earthworms

ABSTRACT

Inagro-ecosystems,fertilizationpracticesarecrucialforsustainingcropproductivity.Here,basedona 50-yearlong-termexperiment,we studiedtheinfluenceoffertilization practices(inorganicand/or organic)andnitrogen(N)applicationrateson(i)soilphysicochemicalproperties,(ii)microbialand earthwormcommunitiesand(iii)cropproduction.Ourresultsshowedthatsoilorganiccarboncontent wasincreasedbyincorporationofcropresidues(+2.45%)andfarmyardmanureapplication(+6.40%)in comparisontotheuseofmineralfertilizeralone.Incontrast,soilcarbonstockwasnotsignificantly affected by these fertilization practices. Overall, only farmyard manure application improved soil physicochemicalproperties comparedtomineral fertilization alone.Soil microbialpopulationwas enhanced by the application of organic amendments as indicated by microbial biomass and phospholipid-derived fatty acids contents. The fertilization practices and the N application rates affectedsignificantlyboththebiomassandcompositionofearthwormpopulations,especiallytheepigeic andendogeicspecies.Finally,farmyardmanureapplicationsignificantlyincreasedcropyield(+3.5%)in comparisontomineralfertilizationalone.Cropresidueincorporationrenderedvariablebutsimilarcrop yieldsoverthe50-yearperiod.Theresultsofthislong-termexperimentindicatethattheuseoforganic amendmentsnotonlyreducestheneedforhigheramountofmineralNfertilizerbutalsoimprovesthe soilbiologicalpropertieswithdirecteffectsoncropyield.

ã2016Agroscope.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1.Introduction

Inagro-ecosystems,fertilizationpracticesinfluencesoilquality and cropproductivity.Depending onthe natureof theapplied fertilizer(organic or inorganic),modificationsof soilproperties havebeenobservedoverthelong-termunderdifferentpedocli- maticconditions (Rasmussenet al.,1998).Thespecializationof farmingactivitieshasledtothespatialsegregationofcropand livestockproductions,thuscausingadrasticdecreaseintheuseof animalmanureasorganicamendmentinmanyconventionalfarms in Switzerland (Vullioud et al., 2004) and more generally in westernEurope(Chesworth,2008).Asaresult,thenecessityfor maintainingsoilorganiccarbon(SOC)atsufficientlevelsinarable fieldshasbecomeanimportantissue.

Soilorganiccarbonisacrucialparameterforsoilfertilityasit enhances soil physical, chemical and biological properties (Birkhoferetal.,2008;Lützowetal.,2006).Indeed,anincrease of SOC content may promote crop yields through increased nutrientsupply(HaynesandNaidu,1998;Maltasetal.,2013)and improved water retention capacity (Edmeades, 2003). Further- more, SOC contributes to the attenuation of environmental impactsoffarmingactivitiessothat,forexample,soilerosionis reduced (Six et al., 2002) and nutrient leaching is minimized (Drinkwateretal., 1998).Soilorganicmatter(SOM)isalsothemost importantterrestrialpoolforcarbon(C)sequestration(Lal,2002), and its management is thereforerelevant for themitigationof climatechange(Lal,2004).

Thedynamicofsoilorganiccarbon(SOC)isdirectlyrelatedto the amount of C supplied to the soil and the rate of SOM decomposition (Lal, 2002). In agro-ecosystems, fertilization practicesinfluenceSOCcontentbymodifyingbothC inputsand

*Correspondingauthor.

E-mailaddress:sokrat.sinaj@agroscope.admin.ch(S.Sinaj).

http://dx.doi.org/10.1016/j.agee.2016.05.032

0167-8809/ã2016Agroscope.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

ContentslistsavailableatScienceDirect

Agriculture, Ecosystems and Environment

j o u r n al h o m e p a g e: w w w . el s e v i e r . c o m / l o c at e / a g e e

losses (Follett, 2001). In general, the application of organic amendments such as crop residues and/or farmyard manure increases significantly SOC (Diacono and Montemurro, 2010;

Lützowetal.,2006;Maltasetal.,2013),whereasthelong-term application of only inorganic fertilizers often has the opposite effect (Edmeades, 2003). The decomposition rate of SOM is influencedbymanyfactorssuchas(i)thechemicalcomposition and the molecular structure of organic matter (OM) (Kögel- Knabner, 2002); (ii) the physical protection of OM within soil aggregates(Sixetal.,2002)and/or(iii)thesoilbiologicalactivity (Condronetal.,2010).Sinceprocessesinvolvedintheaccumula- tionand/orthemineralization ofSOM canbeparticularlyslow (Diacono and Montemurro, 2010; Rasmussen et al., 1998), the relativeimportanceofsoilpropertiesandfarmpracticesonSOC dynamicsshouldbeevaluatedinlong-termexperiments.

Greenmanureand/orcropresiduesincorporation havebeen proposedasalternativecroppingsystemsinordertoreduceSOC losswhenfarmyardmanureisunavailable(Drinkwateretal.,1998;

Zhaoetal.,2009).However,thesepracticesarerelativelyrecent and most of the studies regarding the effect of crop residue incorporation on SOChave been performed onrelatively short timescales,generallyoveradecadeortwo.Thelongtermeffectof cropresiduesincorporationisthereforestillunderdiscussion(Liu et al., 2014; Powlson et al., 2011) especially if pedoclimatic conditionsaretakenintoaccount(Poeplauetal.,2015).

Soil biological communities are particularly sensitive to agriculturalpracticessustainingSOC(Mäderetal.,2002),assoil SOCistheirprincipalfeedingsubstrate.Biologicalprocessesare crucial for themaintenance ofsoil fertilitydue totheirrole in nutrientcycling.Forinstance,soilbiotaplaysamajorroleinthe mineralizationoftheSOM,inthefixationofatmosphericnitrogen, orinthereductionofnutrientlossesbyimmobilizingtemporarily nutrients in the biomass. In addition, particular biological communities enhance plant nutrient uptake (e.g. mycorrhizal fungi) (Johansson et al., 2004) or improve soil texture (e.g.

earthworms)(Bertrandetal.,2015).Asconsequence,diversified biological communities in agroecosystemscan offer a panelof ecologicalservicesthatultimatelyenhance thesustainabilityof cropproduction(Altieri,1999).

Nevertheless,intensiveagriculturalpractices inconventional farmingsystemsnegativelyimpactthesoilbiologicalcommunities of agroecosystemsdue tothedisturbanceinduced bychemical fertilizer,pestcontrolmeasuresorsoiltillage(Bertrandetal.,2015;

GeisselerandScow,2014;Zhaoetal.,2014).InSwitzerland,the DOK (“biologisch-Dynamische, Organisch-biologische und Konven- tionelle”)experiment(Mäderetal.,2002)comparesthelongterm effectsofdifferentorganicandconventionalfarmingsystems,but little is still known about the comparative impact of different variants of conventional fertilization management on SOC and biologicalproperties.Therefore,theobjectivesofthepresentstudy weretoevaluatethelong-terminfluenceoffertilizationpractices on (i) soil C storage and soil physic-chemical properties, (ii) microbialandearthwormcommunitiesand(iii)cropyields.Inthis study, results of the oldest long-term field experiment in Switzerland,which startedin1963,arepresented.In aconven- tional farming system, the effects of two different organic amendments (farmyard manure application and crop residues incorporation)werecomparedtotheconventionaluseofmineral fertilizersalone.

2.Materialsandmethods

2.1.Sitedescriptionandexperimentaldesign

Theexperimentwasestablishedin1963bytheSwissResearch Station Agroscope in Changins (46
24⁰5.28⁰⁰N, 06
14⁰7.47⁰⁰E,

altitude: 445m) on a Calcaric Cambisol (FAO classification) characterizedby196gkg^1ofclay,345gkg^1ofsand,20.3gkg^1 ofSOCand 7.3ofpHintheploughlayer(0–20cm).Duringthe experimental period 1963–2013, mean annual rainfall and temperaturewere, respectively,1004mm and 9.5
C. Beforethe establishment of the experiment, the area was covered with grassland(alfalfafield).Winterwheatwasplantedoneyearbefore thebeginningoftheexperimentasabuffercrop.Theexperimental designhasundergonesomemodificationssinceitsestablishment.

The original design of the experiment (1963–1970) was a randomized block with three main fertilization practices (FP) and four replications. Thethree FP were: (i) mineralfertilizers alone(MIN),(ii)cropresiduesincorporationwithreducedmineral fertilization (RES) and (iii) cattle farmyard manure application (10tha^1year^1)withreducedmineralfertilization(FYM).In1971, two different levels of mineral nitrogen (N) fertilization were introducedassub-treatmentstoallthreefertilizerpractices,thus convertingtheexperimentaldesignintoasplit-plotone,wherethe sizeofeachsubplotwas55m²(5mx11m).Adoseof120kgNha^1 (N120), considered optimal according tothe Swiss fertilization guidelinesforwheatcrop(Sinajetal.,2009),andalimitingdoseof 50kgNha^1 (N50) were applied one or two times during the growthperiodasammoniumnitrate(NH4NO3)accordingtocrop type.

2.2.Fertilizationandagronomicpractices

Thecroprotationchangedtwiceoverthewholeexperimental period. Initiallya‘wheat-maize-wheat’ rotationwas established forthe1963–1972period,followedbytheintegrationofsugarbeet from1972to2008,whichwasthenfinallyreplacedbyrapeseedin 2008(Table1).

Atharvest,cropresiduesweresystematicallyremovedfromthe soil in the case of MIN and FYM main-treatments, but were incorporatedwiththeploughlayer(0–20cm)fortheRESmain- treatment.FYM(compostedcattlemanureoriginatingfromloose housing)wasappliedattherateof10tha^1year^1everytwoor fouryears(Table1)andincorporatedintothesoilwiththeplough beforeplanting.Finally,thesoilwaspreparedwitharotaryharrow (5cm)forplanting.

Phosphorus (P) and potassium (K) fertilizer rates were determinedaccordingtotheSwissfertilizationguidelines(Sinaj et al., 2009) and were the same for all treatments. The recommendedPandKfertilizerratesfromtheSwissfertilization guidelineswereadjusted(reduced)toaccountforthecontribution fromorganicamendments(RESandFYM).Theaverageamountsof PandKappliedasmineralfertilizersarereportedinTable1.Triple superphosphate[Ca(H₂PO₄)₂^H2O] andsaltof potash(KCl)were appliedpriortoplantingforthesummercrops(maize,sugarbeet) andduringthegrowingperiodforothercrops(winterwheatand rapeseed).Herbicideswereapplieddependingonweedpressure, and standardphytosanitaryprotectionwasappliedaccordingto integratedcropprotectionprinciples(Hänietal.,1990).

2.3.Soilsamplingandanalyses

SoilsweresampledinearlyAugust2013,aftertheharvestof winterwheat,fromtheploughlayer(0–20cm).Tencoreswitha diameterof2.5–3cmwererandomlytakenwithineachsub-plot.

Plant residues were removedfrom the soil and the individual samplesmixedtoformacompositesampleperplot.Sampleswere oven-driedat40
Cduring48h,sievedat2mmandanalysedfor differentsoilproperties(Table2).

Soilbulk densitywasmeasuredinearlyApril 2014.Samples weretakenfromthecentralpartofeachplotawayfromanywheel track.Asinglepitwasdugforeachreplicateand6cmdiameter

cylinderswereinsertedintothesoilat2–8and12–18cmbelow soilsurface.Soilsampleswereoven-driedat105
Cduring72hand weighed(FALetal.,2004).Thevaluesofbothdepthincrements(2– 8cmand12–18cm)wereaveragedforfurthercalculations.

Duringthesametime,moistsoilsamplesfromtheploughlayer werecollectedfortheestimationofmicrobial nutrientbiomass and thedetermination of phospholipidfatty acids(PLFAs). The earlyspringperiod(April)isconsideredidealforinter-comparison of treatments with regards to soil biology in agro-ecosystems (Kaiseretal.,1995).Sampleswerekeptmoistandsievedat2mm.

Samplesformicrobialbiomassestimationwerestoredat4
Cand

those used for PLFAdetermination werefrozenat 20
C until laboratoryanalysis.

2.4.Soilmicrobialbiomassnutrientsandmicrobialcommunity structure

Microbial biomass carbon(Cmic),nitrogen (Nmic)and phos- phorus (Pmic) were measured according to the fumigation- extractionprocedure(Vanceetal.,1987).TotalCandNofboth fumigated and non-fumigated samples were extracted with 0.5MK2SO4 solution according toa soil:solution ratio of 1:10.

Table2

Effectofthetreatmentsonsoilpropertiesintheploughlayer(0–20cm)in2013.

Analyses FP MIN RES FYM p-value

N N50 N120 N50 N120 N50 N120 FP N FPN

Organicproperties

SOC^a [g.kg^1] 15.10a 15.50a 15.35b 16.00b 16.20b 16.30b <0.001 n.s n.s

Ntota

[g.kg^1] 1.85 1.91 1.79 1.83 1.97 1.95 n.s n.s n.s

C/Nratio [] 7.64 7.88 8.23 8.38 8.21 8.79 n.s n.s n.s

Cstock^b [Mg.ha^1] 37.37 37.96 37.85 38.67 39.25 40.62 n.s n.s n.s

Physicalproperties

Bulkdensity [g.cm^3] 1.47 1.48 1.50 1.49 1.44 1.46 n.s n.s n.s

Chemicalproperties

pH^a [H2O] 7.75 7.70 7.66 7.80 7.75 7.56 n.s n.s n.s

CEC^a [meq.kg^1] 106.11 102.77 103.79 107.46 113.28 108.68 n.s n.s n.s

Ptotc

[g.kg^1] 0.98 0.96 0.96 0.91 0.96 0.96 n.s n.s n.s

Porgc [g.kg^1] 0.35 0.33 0.32 0.32 0.33 0.33 n.s n.s n.s

PAAEd

[mg.kg^1] 102.24b 84.70b 81.25a 61.16a 99.53b 83.18b 0.021 n.s n.s

Ktot [g.kg^1] 15.19 16.56 16.32 15.97 15.60 15.98 n.s n.s n.s

KAAEd

[mg.kg^1] 185.60b 168.83b 135.40a 106.77a 148.33ab 157.40ab 0.008 n.s n.s

Displayedvaluesareaveragesoffourreplicates.p-valuesofeachfactorarecomputedaccordingtoanANOVAperformedafterthefittingofalinearmixedeffectsmodel.The abbreviation“n.s”standsfor“notsignificant”.LettersrefertotheresultsofTukey’sHSDtestandareonlydisplayedifthesignificancethreshold(p<0.05)isreached.In addition,uppercaselettersrefertothepairwisecomparisonofNratesandlowercaseletterstofertilizationpractices.

aSOC,totalN,pH-waterandCECaremeasuredaccordingtotheSwissstandardmethods(FALetal.,2004).

b SoilCstockoftheuppersoillayerwasestimatedusingtheminimumEquivalentSoilMass(ESM)correction(Leeetal.,2009).

cTotalandorganic-Paremeasuredaftersoilincinerationat550
Cduring1handextractionoftheasheswith0.5MH2SO4(SaundersandWilliams,1955).

d P-andK-AAEareextractedwithammoniumacetateandEDTAaccordingtotheSwissstandardmethods(FALetal.,2004).

Table1

Appliedphosphorusandpotassiumfertilization(kgha^1)overtheexperimentalperiod.

Period Crop MIN RES FYM

P K P K P K Manureapplication

1963–1971 WinterWheat 39 125 39 125 39 125 30t/3years

Maize 39 125 39 125 39 125

1972–1975 Sugarbeet 44 349 31* 166* 31 166 40t/4years

WinterWheat 35 100 31* 125* 22 83

Maize 52 166 35* 50* 26 166

SpringWheat 35 100 35* 100* 35 100

1976–1995 Sugarbeet 44 249 39* 199* 24 174 40t/4years

WinterWheat 31 100 26* 0* 11 25

Maize 44 174 39* 125* 44 125

WinterWheat 31 100 26* 66* 26* 66*

1996–2007 Sugarbeet 52 224 48* 33* 39 100 40t/4years

WinterWheat 17 75 0* 0* 0 0

Maize 52 224 48* 33* 39 100

WinterWheat 17 75 0* 0* 0* 0*

Since2008 Rapeseed 52 224 48* 33* 39 100 20t/2years

WinterWheat 17 75 0* 0* 0* 0*

Maize 52 224 48* 33* 39 100

WinterWheat 17 75 0* 0* 0 0

Asterisks(*)indicatethatcropresiduesoftheprecedingyearwereincorporatedintothesoilaftertheirharvest.