Organic Crop Production – Ambitions and Limitations

246 Pages·2008·3.11 MB·English

by  Lars Bergström

Organic Crop Production – Ambitions
and Limitations
·
Holger Kirchmann Lars Bergstro¨m
Editors
Organic Crop Production –
Ambitions and Limitations
123
Editors
Dr.HolgerKirchmann Dr.LarsBergstro¨m
SwedishUniversity SwedishUniversity
ofAgriculturalSciences ofAgriculturalSciences
Dept.ofSoilandEnvironment Dept.ofSoilandEnvironment
P.O.Box7014 P.O.Box7014
SE-75007Uppsala SE-75007Uppsala
Sweden Sweden
ISBN978-1-4020-9315-9 e-ISBN978-1-4020-9316-6
DOI10.1007/978-1-4020-9316-6
LibraryofCongressControlNumber:2008938183
(cid:2)c SpringerScience+BusinessMediaB.V.2008
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Preface
Organicagricultureisbeingpromotedagainstabackgroundofintensivediscussions
aboutproductionmethods,foodandfeedqualityandrenewableresources,withthe
overallaimoflong-termsustainability.Organicagricultureisasubjectthattriggers
manydifferentresponsesinpeople.Someareconvincedthatitisthewayforward,
whileothersquestionitsbenefitsandthewisdomofitslarge-scaleimplementation.
Even among the scientific community, different views have developed over recent
decades.
Organicagricultureispromotedinanumberofpopularandscientificbooksand
isoftendescribedasbeingsuperior,thesolutiontocommonagriculturalproblems
andameansofproducingbetterfood.Organicagricultureisoftenviewedasbeing
environmentallysoundandsuperiortoconventionalagriculturethroughtheexclu-
sion of synthetic fertilisers and pesticides. As a result, any questioning of organic
practices is unpopular and criticism is often interpreted as impeding the develop-
ment of sustainable systems. In addition, scientifically-based information contra-
dictingtheclaimsmadefororganicagriculturecanbedifficulttocommunicateand
canberegardedasastepbackwardsandagainstpoliticalmainstreamopinion.
The topic was discussed at a Symposium at the 18th World Congress of Soil
Science in Philadelphia in 2006, where benefits and problems relating to organic
cropproductionwerepresented.Someofthekeyfindingsfromthatsymposiumare
presentedinthisbook,togetherwithothercentralaspectsoforganiccropproduc-
tion.Theaimofthisbookistoprovidethereaderswithaclear,scientifically-based
overviewofanumberofrelevantsubjectsrelatingtoorganiccropproductionsothat
theycanformabalancedpictureofthisfoodproductionapproach.
Weareverythankfultoallthecontributingauthorsforprovidingtheirin-depth
viewsinthevariouschapters.Wewouldalsoliketoacknowledgealltheanonymous
reviewerswhohelpedtoimprovethequalityofthedifferentchaptersandDrMary
McAfee for excellent linguistic advice. Finally, we would like to thank Springer
forpublishingthebook,whichwehopewillprovideabetterunderstandingoftrue
long-termsustainabilityinfuturecropproduction.
Uppsala,Sweden HolgerKirchmann
July2008 LarsBergstro¨m
v
Contents
1 Widespread Opinions About Organic Agriculture – Are They
SupportedbyScientificEvidence? ............................... 1
LarsBergstro¨m,HolgerKirchmannandGudniThorvaldsson
2 FundamentalsofOrganicAgriculture–PastandPresent............ 13
Holger Kirchmann, Gudni Thorvaldsson, Lars Bergstro¨m, Martin
Gerzabek,OlofAndre´n,Lars-OlovErikssonandMikaelWinninge
3 CanOrganicCropProductionFeedtheWorld? ................... 39
HolgerKirchmann,LarsBergstro¨m,ThomasKa¨tterer,OlofAndre´n
andRuneAndersson
4 PlantNutrientsinOrganicFarming.............................. 73
KeithGoulding,ElizabethStockdaleandChristineWatson
5 NutrientSupplyinOrganicAgriculture–PlantAvailability,Sources
andRecycling.................................................. 89
HolgerKirchmann,ThomasKa¨ttererandLarsBergstro¨m
6 Synthesis of the Apelsvoll Cropping System Experiment in
Norway–NutrientBalances,UseEfficienciesandLeaching.........117
AudunKorsaethandRagnarEltun
7 Use Efficiency and Leaching of Nutrients in Organic and
ConventionalCroppingSystemsinSweden........................143
Lars Bergstro¨m, Holger Kirchmann, Helena Aronsson, Gunnar
TorstenssonandLennartMattsson
8 HowWillConversiontoOrganicCerealProductionAffectCarbon
StocksinSwedishAgriculturalSoils?.............................161
OlofAndre´n,ThomasKa¨ttererandHolgerKirchmann
vii
viii Contents
9 EnergyAnalysisofOrganicandConventional
AgriculturalSystems ...........................................173
Go¨teBertilsson,HolgerKirchmannandLarsBergstro¨m
10 TheRoleofArbuscularMycorrhizasinOrganicFarming ..........189
MeganH.RyanandMarkTibbett
11 OrganicFoodProductionandItsInfluenceonNaturallyOccurring
Toxins ........................................................231
CarlK.Winter
Index .............................................................241
Contributors
RuneAndersson DepartmentofFoodScience,SwedishUniversityofAgricultural
Sciences,P.O.Box7051,SE-75007Uppsala,Sweden
OlofAndre´n DepartmentofSoilandEnvironment,SwedishUniversityofAgricul-
turalSciences,P.O.Box7014,SE-75007Uppsala,Sweden,[email protected]
Helena Aronsson Department of Soil and Environment, Swedish University of
AgriculturalSciences,P.O.Box7014,SE-75007Uppsala,Sweden
Lars Bergstro¨m Department of Soil and Environment, Swedish University of
AgriculturalSciences,P.O.Box7014,SE-75007Uppsala,Sweden,
[email protected]
Go¨teBertilsson GreengardAB,P.O.Box552,SE-24495Do¨sjebro,Sweden,
[email protected]
Ragnar Eltun Bioforsk Arable Crops Division, Norwegian Institute for Agricul-
turalandEnvironmentalResearch,Apelsvoll,N-2849Kapp,Norway
Lars-Olov Eriksson Johannelunds Theological University College, Heidenstam-
storg75,SE-75427Uppsala,Sweden
MartinGerzabek InstituteofSoilResearch,UniversityofNaturalResourcesand
AppliedLifeSciences,Peter-Jordan-Straße82,A-1190Vienna,Austria
KeithGoulding Cross-InstituteProgrammeforSustainableSoilFunction,Rotham-
stedResearch,Harpenden,Hertfordshire,AL52JQ,UK,
[email protected]
Thomas Ka¨tterer Department of Soil and Environment, Swedish University of
AgriculturalSciences,P.O.Box7014,SE-75007Uppsala,Sweden
ix
x Contributors
Holger Kirchmann Department of Soil and Environment, Swedish University of
AgriculturalSciences,P.O.Box7014,SE-75007Uppsala,Sweden,
[email protected]
Audun Korsaeth Bioforsk Arable Crops Division, Norwegian Institute for Agri-
culturalandEnvironmentalResearch,Apelsvoll,N-2849Kapp,Norway,
[email protected]
Lennart Mattsson Department of Soil and Environment, Swedish University of
AgriculturalSciences,P.O.Box7014,SE-75007Uppsala,Sweden
Megan H. Ryan School of Plant Biology, University of Western Australia, 35
StirlingHwy,Crawley,WA,Australia,6009,[email protected]
Elizabeth Stockdale School of Agriculture Food and Rural Development, King
GeorgeVIBuilding,NewcastleUniversity,Newcastle-upon-Tyne,NE17RU,UK
MarkTibbett SchoolofEarthandGeographicalSciences,CentreforLandReha-
bilitation,UniversityofWesternAustralia,35StirlingHwy,Crawley,WA,Australia,
6009
Gudni Thorvaldsson Agricultural University of Iceland, Keldnaholti, IS-112
Reykjavik,Iceland
GunnarTorstensson DepartmentofSoilandEnvironment,SwedishUniversityof
AgriculturalSciences,P.O.Box7014,SE-75007Uppsala,Sweden
ChristineWatson SACAberdeen,FergusonBuilding,CraibstoneEstate,Aberdeen,
AB219YA,UK
Mikael Winninge Department of Religious Studies, Umea˚ University, SE-90187
Umea˚,Sweden
Carl K. Winter Department of Food Science and Technology, University of
CaliforniaDavis,CA95616,USA,[email protected]
Chapter1
Widespread Opinions About Organic Agriculture
– Are They Supported by Scientific Evidence?
LarsBergstro¨m,HolgerKirchmannandGudniThorvaldsson
Abstract Organic agriculture ostensibly offers a concept of sustainable practices
basedonenvironmentalresponsibility.Itiswidelybelievedthatorganicprinciples
basedonnaturalmeansandmethodsareenvironmentallysoundandthussuperiorto
systemsbasedonartificialinputs.Thisoverviewsummarisesthemainresultsonor-
ganicagricultureandhighlightsrelevantfactsinordertoprovidescientificinformation
aboutthepotentialandlimitationsoforganicagriculture.Thetopicsoffoodsecurity
andsafety,environmentalquality,systemsustainabilityandenergyconsumptionare
addressed.Someofthemainconclusionsarethatorganicagriculturehasconsistently
loweryieldsthanconventionalproductionandistherebyalessefficientmethodof
landuse;thatenvironmentalproblemscausedbyprocessessuchasnutrientleach-
ingarenotreducedbyconversiontoorganiccropproduction;andthatsoilfertility
statusandmicrobialbiodiversityarenotimprovedaprioribyorganiccropping.The
energyinvestmentforproductionofartificialNfertilisersresultsinafive-toten-fold
energyreturnintheformofbiomassandthishighlypositiveenergybalanceneeds
tobefullyacknowledged.Thefuturechallengeofdevelopingsustainableformsof
agriculturetoprovidesufficientfoodforagrowingworldpopulationwithminimal
environmentaldisturbancedeservesourwholeheartedandunbiasedattention.
Keywords Carbonsequestration·Energyissues·Foodproduction·Naturaltoxins·
Nutrientleaching·Pesticideresidues·Soilfertility
1.1 Introduction
Duringthepasttwodecades,organicagriculturehasoftenbeenpresentedasbeing
superiortoconventionalproductioninmanyrespects.Thishasledtoawidespread
belief among the general public that organic crop production is better and in an
ambitiontosatisfythisopinion,politiciansandlegislatorshavestronglypromoted
L.Bergstro¨m( )
B
DepartmentofSoilandEnvironment,SwedishUniversityofAgriculturalSciences,P.O.Box7014,
SE-75007Uppsala,Sweden
e-mail:[email protected]
H.Kirchmann,L.Bergstro¨m(eds.),OrganicCropProduction–Ambitions 1
andLimitations,DOI10.1007/978-1-4020-9316-6 1,
(cid:2)C SpringerScience+BusinessMediaB.V. 2008
2 L.Bergstro¨metal.
this type of agriculture. For example, in Sweden the political goal has been to in-
crease the area used for organic production to 20% of all arable soils. In addition,
organicallyproducedfoodshouldconstitute25%ofthefoodusedinstateschools,
hospitalsandresidentialhomesfortheelderly.Themaindrivingforceshavebeen
togeneratebenefitsfortheenvironmentandtoimprovefoodquality.Morerecently,
impacts on energy consumption, climate change and long-term sustainabilityhave
alsobeeninfocus.
Buying organically produced food, and thereby supporting all these benefits,
creates a feelgood factor for consumers of organically produced food. For many
people,organicallyproducedfoodisalwaysbetterevenifitrequireslong-distance
transport. However, the question is whether these common opinions circulating in
societyaresupportedbythescientificevidence.
Theprinciplesoforganicpracticesderivefromnaturalphilosophiesandnotnatu-
ralsciences.Adeeperscientifically-basedanalysisoflong-termorganicfieldexperi-
ments–whichisthemainfocusofthisbook–givesadifferentpictureofthebenefits
generated.However,scientificcomparisonsoforganicandconventionalfarmingare
unappealingtosocietysincetheyprovideevidencethatman-madeinventions,such
as artificial fertilisers, often lead to production of crops in larger quantities and of
goodquality.Thisisincontrasttothecommonbeliefthatweshouldalwaysfollow
rulesdeterminedbynature.
In this introductory chapter, we present some common opinions about organic
agriculture and discuss them briefly in the context of the results presented in the
otherchaptersofthisbook.Thefollowingtopicsrelatingtoorganicagricultureare
addressed:
(cid:2)
(cid:2) Foodsecurityandsafety
(cid:2) Environmentalquality
(cid:2) Systemsustainability
Energyconsumption.
1.2 WidespreadOpinionsVersusScientificEvidence
1.2.1 FoodIssues
Sincetheintroductionoforganicagricultureinthe1920s,foodqualityissueshave
beenaparticularfocus.Oneofthefoundersoforganicagriculture,RudolfSteiner
(1924), believed that artificial fertilisers would degenerate agricultural produce to
suchanextentthattheywouldnotbefitforhumanconsumptionbytheendofthe
20thcentury.Concernaboutlevelsofyieldonlyenteredtheagendamuchlater.
1.2.1.1 FoodSecurity
A general opinion in society is that conversion to organic crop production is fol-
lowed by little or no yield reduction and that organic crop production is therefore