scholarly journals Reviews and syntheses: Review of causes and sources of N<sub>2</sub>O emissions and NO<sub>3</sub> leaching from organic arable crop rotations

2019 ◽  
Vol 16 (14) ◽  
pp. 2795-2819 ◽  
Author(s):  
Sissel Hansen ◽  
Randi Berland Frøseth ◽  
Maria Stenberg ◽  
Jarosław Stalenga ◽  
Jørgen E. Olesen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
Crop Residues ◽  
Cropping Systems ◽  
Crop Rotations ◽  
N2o Emissions ◽  
Arable Crop ◽  
Organic Fertilisers ◽  
N2o Fluxes

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 N-input 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.

scholarly journals Review of key causes and sources for N<sub>2</sub>O emissions and NO<sub>3</sub>-leaching from organic arable crop rotations

2018 ◽  
Author(s):  
Sissel Hansen ◽  
Randi Berland Frøseth ◽  
Maria Stenberg ◽  
Jarosław Stalenga ◽  
Jørgen E. Olesen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Nitrate Leaching ◽  
Organic Production ◽  
Crop Rotations ◽  
Organic Fertilizers ◽  
N2o Emissions ◽  
Catch Crops ◽  
Arable Crop ◽  
N2o Fluxes ◽  
The Impact

Abstract. The emissions of nitrous oxide (N2O) and leaching of nitrate (NO3) have considerable negative impacts on climate and the environment. Although these environmental burdens are on average less per unit area in organic than in non-organic production, they are not smaller per unit of product. If organic farming is to maintain its goal of being an environmentally friendly production system, these emissions should be mitigated. We discuss the impact of possible triggers within organic arable farming practice for the risk of N2O emissions and NO3 leaching under European climatic conditions, and possible strategies to reduce these. Organic arable crop rotations can be characterised as diverse with frequent use of legumes, intercropping and organic fertilizers. The soil organic matter content and share of active organic matter, microbial and faunal activity are higher, soil structure better and yields lower, than in non-organic, arable crop rotations. Soil mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is high potential for SMN accumulation and losses after crop termination or crop harvest. The risk for high N2O fluxes is increased when large amounts of herbage or organic fertilizers with readily available nitrogen (N) and carbon are incorporated into the soil or left on the surface. Freezing/thawing, drying/rewetting, compacted and/or wet soil and mixing with rotary harrow further enhance the risk for high N2O fluxes. These complex soil N dynamics mask the correlation between total N-input and N2O emissions from organic arable crop rotations. Incorporation of N rich plant residues or mechanical weeding followed by bare fallow increases the risk of nitrate leaching. In contrast, strategic use of deep-rooted crops with long growing seasons in the rotation reduces nitrate leaching risk. Reduced tillage can reduce N leaching if yields are maintained. Targeted treatment and use of herbage from green manures, crop residues and catch crops will increase N efficiency and reduce N2O emissions and NO3 leaching. Continued regular use of catch crops has the potential to reduce NO3 leaching but may enhance N2O emissions. A mixture of legumes and non-legumes (for instance grasses or cereals) are as efficient a catch crop as monocultures of non-legume species.

Changes in soil carbon under long-term maize in monoculture and legume-based rotation

2001 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
E G Gregorich ◽  
C F Drury ◽  
J A Baldock
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Magnetic Resonance ◽  
Soil Carbon ◽  
Crop Residues ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Organic C ◽  
Soil C

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon

Site specific impacts of climate change on crop rotations and their management in Brandenburg/Germany

2020 ◽  
Author(s):  
Kurt-Christian Kersebaum ◽  
Susanne Schulz ◽  
Evelyn Wallor
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
Crop Production ◽  
Capillary Rise ◽  
Crop Rotations ◽  
Climate Conditions ◽  
Soil Map ◽  
Digital Soil Map

&lt;p&gt;Climate change impact on crop production depends on the cultivated crop and its position within crop rotations and on site conditions, e.g. soils and hydrology, buffering adverse weather situations. We present a regional study across the federal state of Brandenburg/Germany based on gridded climate data and a digital soil map using the HERMES-to-Go model. The aim was to investigate defined crop rotations and common agricultural practices under current and future climate conditions regarding productivity and environmental effects. Two contrasting GCMs (HAD and MPI) were used to generate climate input for modelling for the RCPs 2.6 and 8.5.&lt;/p&gt;&lt;p&gt;5 different types of crop production were simulated by defining crop rotations over 4-5 years for soil quality rating groups. While one rotation is comprised by the most common crops, another rotation modifies the first one by introducing a legume followed by a more demanding crop. The third rotation intends to produce higher value crops, e.g. potatoes than the first one, while the fourth rotation has its focus on fodder grass and cereal production. Building on this the fifth rotation replaces the fodder grass by alfalfa. All rotations are simulated in shifted phases to ensure that each crop is simulated for each year.&lt;/p&gt;&lt;p&gt;Sowing, harvest and nitrogen fertilization were derived by algorithms based on soil and climate information to allow self-adaptation to changing climate conditions. The crop rotations are simulated under rainfed and irrigated conditions and with and without the implementation of cover crops to prevent winter fallow.&lt;/p&gt;&lt;p&gt;We used the digital soil map 1:300.000 for Brandenburg with 99 soil map units. Within the soil map unit, up to three dominant soil types were considered to achieve at least 65% coverage. 276 soil types are defined by their soil profiles including soil organic matter content and texture down to 2 meters. Groundwater levels are estimated using the depth of reduction horizons as constant values over the year, to consider capillary rise depending on soil texture and distance between the root zone and the groundwater table.&lt;/p&gt;&lt;p&gt;In total each climate scenario contains about 148.000 simulations of 30 years. Beside crop yields we analyse the outputs for trends in soil organic matter, groundwater recharge, nitrogen leaching and the effect on water and nitrogen management using algorithms for automatic management.&lt;/p&gt;&lt;p&gt;Results indicate that spring crops were more negatively affected by climate change than winter crops especially on soils with low water holding capacity. However, few areas with more loamy soils and potential contribution of capillary rise from a shallow groundwater even benefited from climate change. Irrigation in most cases improved crop yield especially for spring crops. However, further analysis is required to assess if irrigation gains an economic benefit for all crop rotations. Nitrogen leaching can be reduced by implementing winter cover crops. Soil organic matter is assessed to decline for most sites and rotations. Only the rotations with multiyear grass or alfalfa can keep the level, but not on all sites.&lt;/p&gt;

scholarly journals European Perspectives on the Adoption of Nonchemical Weed Management in Reduced-Tillage Systems for Arable Crops

2013 ◽  
Vol 27 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Bo Melander ◽  
Nicolas Munier-Jolain ◽  
Raphaël Charles ◽  
Judith Wirth ◽  
Jürgen Schwarz ◽  
...  
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Crop Residues ◽  
Cropping Systems ◽  
Management Strategies ◽  
Crop Protection ◽  
Crop Rotations ◽  
Future Research ◽  
Reduced Tillage ◽  
Tillage Systems

Noninversion tillage with tine- or disc-based cultivations prior to crop establishment is the most common way of reducing tillage for arable cropping systems with small grain cereals, oilseed rape, and maize in Europe. However, new regulations on pesticide use might hinder further expansion of reduced-tillage systems. European agriculture is asked to become less dependent on pesticides and promote crop protection programs based on integrated pest management (IPM) principles. Conventional noninversion tillage systems rely entirely on the availability of glyphosate products, and herbicide consumption is mostly higher compared to plow-based cropping systems. Annual grass weeds and catchweed bedstraw often constitute the principal weed problems in noninversion tillage systems, and crop rotations concurrently have very high proportions of winter cereals. There is a need to redesign cropping systems to allow for more diversification of the crop rotations to combat these weed problems with less herbicide input. Cover crops, stubble management strategies, and tactics that strengthen crop growth relative to weed growth are also seen as important components in future IPM systems, but their impact in noninversion tillage systems needs validation. Direct mechanical weed control methods based on rotating weeding devices such as rotary hoes could become useful in reduced-tillage systems where more crop residues and less workable soils are more prevalent, but further development is needed for effective application. Owing to the frequent use of glyphosate in reduced-tillage systems, perennial weeds are not particularly problematic. However, results from organic cropping systems clearly reveal that desisting from glyphosate use inevitably leads to more problems with perennials, which need to be addressed in future research.

Soil organic matter changes and crops responses to fertiliser under conservation cropping systems in the semi-arid tropics of North Queensland, Australia

1995 ◽  
Vol 35 (2) ◽  
pp. 233 ◽  
Author(s):  
AL Cogle ◽  
J Littlemore ◽  
DH Heiner
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Cropping Systems ◽  
Crop Rotations ◽  
Land Resource ◽  
N Removal ◽  
Resource Protection ◽  
Careful Management ◽  
Semi Arid

Soil organic matter changes due to cropping in the semi-arid tropics were studied in an area with cropping potential. Soil organic carbon and total nitrogen (N) decreased after clearing and tillage, but decline was less where pasture-crop rotations were used. Crop N removal was high and exceeded the recommended fertiliser N rate. These results suggest that if cropping expansion occurs, careful management the is necessary for long-term productivity and land resource protection.

Chemical composition of cover crops and soil organic matter pools in no‐tillage systems in the Cerrado

2021 ◽  
Author(s):  
Arminda Moreira de Carvalho ◽  
Luana Ramos Passos Ribeiro ◽  
Robélio Leandro Marchão ◽  
Alexsandra Duarte de Oliveira ◽  
Karina Pulrolnik ◽  
...  
Keyword(s):  
Organic Matter ◽  
Chemical Composition ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
No Tillage ◽  
Tillage Systems

scholarly journals Nitrogen Immobilisation and Microbial Biomass Build-Up Induced by Miscanthus x giganteus L. Based Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Triticum Aestivum L ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Miscanthus X Giganteus ◽  
Organic Fertilisers ◽  
Biomass N ◽  
Set Up

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.

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