Reviews and syntheses: Review of causes and sources of N2O emissions and NO3 leaching from organic arable crop rotations

Sissel Hansen*, Randi Frøseth, Maria Stenberg, Jaroslaw Stalenga, Jorgen E Olesen, Maike Krauss, Pawel Radzikowski, Jordi Doltra, Shahid Nadeem, Torfinn Torp, AV Pappa, CA Watson

*Corresponding author for this work

Research output: Contribution to journalReview article

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Abstract

The emissions of nitrous oxide (N2O) and leaching
of nitrate (NO3) from agricultural cropping systems have
considerable negative impacts on climate and the environment.
Although these environmental burdens are less per
unit area in organic than in non-organic production on average,
they are roughly similar per unit of product. If organic
farming is to maintain its goal of being environmentally
friendly, these loadings must be addressed. We discuss
the impact of possible drivers of N2O emissions and NO3
leaching within organic arable farming practice under European
climatic conditions, and potential strategies to reduce
these. Organic arable crop rotations are generally diverse
with the frequent use of legumes, intercropping and
organic fertilisers. The soil organic matter content and the
share of active organic matter, soil structure, microbial and
faunal activity are higher in such diverse rotations, and the
yields are lower, than in non-organic arable cropping systems
based on less diverse systems and inorganic fertilisers. Soil
mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential for
SMN accumulation and losses after crop termination, harvest
or senescence. The risk of high N2O fluxes increases when
large amounts of herbage or organic fertilisers with readily
available nitrogen (N) and degradable carbon are incorporated
into the soil or left on the surface. Freezing/thawing,
drying/rewetting, compacted and/or wet soil and mechanical
mixing of crop residues into the soil further enhance the
risk of high N2O fluxes. N derived from soil organic matter
(background emissions) does, however, seem to be the
most important driver for N2O emission from organic arable
crop rotations, and the correlation between yearly total Ninput
and N2O emissions is weak. Incorporation of N-rich
plant residues or mechanical weeding followed by bare fallow
conditions increases the risk of NO3 leaching. In contrast,
strategic use of deep-rooted crops with long growing
seasons or effective cover crops in the rotation reduces NO3
leaching risk. Enhanced recycling of herbage from green manures,
crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissions
and NO3 leaching. Mixtures of legumes (e.g. clover or vetch)
and non-legumes (e.g. grasses or Brassica species) are as efficient
cover crops for reducing NO3 leaching as monocultures
of non-legume species. Continued regular use of cover
crops has the potential to reduce NO3 leaching and enhance
soil organic matter but may enhance N2O emissions. There
is a need to optimise the use of crops and cover crops to enhance
the synchrony of mineralisation with crop N uptake to
enhance crop productivity, and this will concurrently reduce
the long-term risks of NO3 leaching and N2O emissions.
Original languageEnglish
Pages (from-to)2795-2819
Number of pages25
JournalBiogeosciences
Volume16
Issue number14
Early online date17 Jul 2019
DOIs
Publication statusFirst published - 17 Jul 2019

Fingerprint

crop rotation
nitrous oxide
leaching
synthesis
crop
crops
cover crop
soil organic matter
cover crops
crop residue
crop residues
cropping practice
legumes
fertilizer
mechanical weed control
forage
arable farming
organic matter
soil
rewetting

Cite this

Hansen, Sissel ; Frøseth, Randi ; Stenberg, Maria ; Stalenga, Jaroslaw ; Olesen, Jorgen E ; Krauss, Maike ; Radzikowski, Pawel ; Doltra, Jordi ; Nadeem, Shahid ; Torp, Torfinn ; Pappa, AV ; Watson, CA. / Reviews and syntheses: Review of causes and sources of N2O emissions and NO3 leaching from organic arable crop rotations. In: Biogeosciences. 2019 ; Vol. 16, No. 14. pp. 2795-2819.
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abstract = "The emissions of nitrous oxide (N2O) and leachingof nitrate (NO3) from agricultural cropping systems haveconsiderable negative impacts on climate and the environment.Although these environmental burdens are less perunit area in organic than in non-organic production on average,they are roughly similar per unit of product. If organicfarming is to maintain its goal of being environmentallyfriendly, these loadings must be addressed. We discussthe impact of possible drivers of N2O emissions and NO3leaching within organic arable farming practice under Europeanclimatic conditions, and potential strategies to reducethese. Organic arable crop rotations are generally diversewith the frequent use of legumes, intercropping andorganic fertilisers. The soil organic matter content and theshare of active organic matter, soil structure, microbial andfaunal activity are higher in such diverse rotations, and theyields are lower, than in non-organic arable cropping systemsbased on less diverse systems and inorganic fertilisers. Soilmineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential forSMN accumulation and losses after crop termination, harvestor senescence. The risk of high N2O fluxes increases whenlarge amounts of herbage or organic fertilisers with readilyavailable nitrogen (N) and degradable carbon are incorporatedinto the soil or left on the surface. Freezing/thawing,drying/rewetting, compacted and/or wet soil and mechanicalmixing of crop residues into the soil further enhance therisk of high N2O fluxes. N derived from soil organic matter(background emissions) does, however, seem to be themost important driver for N2O emission from organic arablecrop rotations, and the correlation between yearly total Ninputand N2O emissions is weak. Incorporation of N-richplant residues or mechanical weeding followed by bare fallowconditions increases the risk of NO3 leaching. In contrast,strategic use of deep-rooted crops with long growingseasons or effective cover crops in the rotation reduces NO3leaching risk. Enhanced recycling of herbage from green manures,crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissionsand NO3 leaching. Mixtures of legumes (e.g. clover or vetch)and non-legumes (e.g. grasses or Brassica species) are as efficientcover crops for reducing NO3 leaching as monoculturesof non-legume species. Continued regular use of covercrops has the potential to reduce NO3 leaching and enhancesoil organic matter but may enhance N2O emissions. Thereis a need to optimise the use of crops and cover crops to enhancethe synchrony of mineralisation with crop N uptake toenhance crop productivity, and this will concurrently reducethe long-term risks of NO3 leaching and N2O emissions.",
author = "Sissel Hansen and Randi Fr{\o}seth and Maria Stenberg and Jaroslaw Stalenga and Olesen, {Jorgen E} and Maike Krauss and Pawel Radzikowski and Jordi Doltra and Shahid Nadeem and Torfinn Torp and AV Pappa and CA Watson",
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month = "7",
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doi = "10.5194/bg-16-2795-2019",
language = "English",
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Hansen, S, Frøseth, R, Stenberg, M, Stalenga, J, Olesen, JE, Krauss, M, Radzikowski, P, Doltra, J, Nadeem, S, Torp, T, Pappa, AV & Watson, CA 2019, 'Reviews and syntheses: Review of causes and sources of N2O emissions and NO3 leaching from organic arable crop rotations', Biogeosciences, vol. 16, no. 14, pp. 2795-2819. https://doi.org/10.5194/bg-16-2795-2019

Reviews and syntheses: Review of causes and sources of N2O emissions and NO3 leaching from organic arable crop rotations. / Hansen, Sissel; Frøseth, Randi; Stenberg, Maria; Stalenga, Jaroslaw; Olesen, Jorgen E; Krauss, Maike; Radzikowski, Pawel; Doltra, Jordi; Nadeem, Shahid; Torp, Torfinn; Pappa, AV; Watson, CA.

In: Biogeosciences, Vol. 16, No. 14, 17.07.2019, p. 2795-2819.

Research output: Contribution to journalReview article

TY - JOUR

T1 - Reviews and syntheses: Review of causes and sources of N2O emissions and NO3 leaching from organic arable crop rotations

AU - Hansen, Sissel

AU - Frøseth, Randi

AU - Stenberg, Maria

AU - Stalenga, Jaroslaw

AU - Olesen, Jorgen E

AU - Krauss, Maike

AU - Radzikowski, Pawel

AU - Doltra, Jordi

AU - Nadeem, Shahid

AU - Torp, Torfinn

AU - Pappa, AV

AU - Watson, CA

PY - 2019/7/17

Y1 - 2019/7/17

N2 - The emissions of nitrous oxide (N2O) and leachingof nitrate (NO3) from agricultural cropping systems haveconsiderable negative impacts on climate and the environment.Although these environmental burdens are less perunit area in organic than in non-organic production on average,they are roughly similar per unit of product. If organicfarming is to maintain its goal of being environmentallyfriendly, these loadings must be addressed. We discussthe impact of possible drivers of N2O emissions and NO3leaching within organic arable farming practice under Europeanclimatic conditions, and potential strategies to reducethese. Organic arable crop rotations are generally diversewith the frequent use of legumes, intercropping andorganic fertilisers. The soil organic matter content and theshare of active organic matter, soil structure, microbial andfaunal activity are higher in such diverse rotations, and theyields are lower, than in non-organic arable cropping systemsbased on less diverse systems and inorganic fertilisers. Soilmineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential forSMN accumulation and losses after crop termination, harvestor senescence. The risk of high N2O fluxes increases whenlarge amounts of herbage or organic fertilisers with readilyavailable nitrogen (N) and degradable carbon are incorporatedinto the soil or left on the surface. Freezing/thawing,drying/rewetting, compacted and/or wet soil and mechanicalmixing of crop residues into the soil further enhance therisk of high N2O fluxes. N derived from soil organic matter(background emissions) does, however, seem to be themost important driver for N2O emission from organic arablecrop rotations, and the correlation between yearly total Ninputand N2O emissions is weak. Incorporation of N-richplant residues or mechanical weeding followed by bare fallowconditions increases the risk of NO3 leaching. In contrast,strategic use of deep-rooted crops with long growingseasons or effective cover crops in the rotation reduces NO3leaching risk. Enhanced recycling of herbage from green manures,crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissionsand NO3 leaching. Mixtures of legumes (e.g. clover or vetch)and non-legumes (e.g. grasses or Brassica species) are as efficientcover crops for reducing NO3 leaching as monoculturesof non-legume species. Continued regular use of covercrops has the potential to reduce NO3 leaching and enhancesoil organic matter but may enhance N2O emissions. Thereis a need to optimise the use of crops and cover crops to enhancethe synchrony of mineralisation with crop N uptake toenhance crop productivity, and this will concurrently reducethe long-term risks of NO3 leaching and N2O emissions.

AB - The emissions of nitrous oxide (N2O) and leachingof nitrate (NO3) from agricultural cropping systems haveconsiderable negative impacts on climate and the environment.Although these environmental burdens are less perunit area in organic than in non-organic production on average,they are roughly similar per unit of product. If organicfarming is to maintain its goal of being environmentallyfriendly, these loadings must be addressed. We discussthe impact of possible drivers of N2O emissions and NO3leaching within organic arable farming practice under Europeanclimatic conditions, and potential strategies to reducethese. Organic arable crop rotations are generally diversewith the frequent use of legumes, intercropping andorganic fertilisers. The soil organic matter content and theshare of active organic matter, soil structure, microbial andfaunal activity are higher in such diverse rotations, and theyields are lower, than in non-organic arable cropping systemsbased on less diverse systems and inorganic fertilisers. Soilmineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential forSMN accumulation and losses after crop termination, harvestor senescence. The risk of high N2O fluxes increases whenlarge amounts of herbage or organic fertilisers with readilyavailable nitrogen (N) and degradable carbon are incorporatedinto the soil or left on the surface. Freezing/thawing,drying/rewetting, compacted and/or wet soil and mechanicalmixing of crop residues into the soil further enhance therisk of high N2O fluxes. N derived from soil organic matter(background emissions) does, however, seem to be themost important driver for N2O emission from organic arablecrop rotations, and the correlation between yearly total Ninputand N2O emissions is weak. Incorporation of N-richplant residues or mechanical weeding followed by bare fallowconditions increases the risk of NO3 leaching. In contrast,strategic use of deep-rooted crops with long growingseasons or effective cover crops in the rotation reduces NO3leaching risk. Enhanced recycling of herbage from green manures,crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissionsand NO3 leaching. Mixtures of legumes (e.g. clover or vetch)and non-legumes (e.g. grasses or Brassica species) are as efficientcover crops for reducing NO3 leaching as monoculturesof non-legume species. Continued regular use of covercrops has the potential to reduce NO3 leaching and enhancesoil organic matter but may enhance N2O emissions. Thereis a need to optimise the use of crops and cover crops to enhancethe synchrony of mineralisation with crop N uptake toenhance crop productivity, and this will concurrently reducethe long-term risks of NO3 leaching and N2O emissions.

U2 - 10.5194/bg-16-2795-2019

DO - 10.5194/bg-16-2795-2019

M3 - Review article

VL - 16

SP - 2795

EP - 2819

JO - Biogeosciences

JF - Biogeosciences

SN - 1726-4170

IS - 14

ER -