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Catch Crop Residues Stimulate N2O Emissions During Spring, Without Affecting the Genetic Potential for Nitrite and N2O Reduction

Duan, Yun-Feng; Hallin, Sara; Jones, Christopher M.; Priemé, Anders; Labouriau, Rodrigo and Petersen, Søren O. (2018) Catch Crop Residues Stimulate N2O Emissions During Spring, Without Affecting the Genetic Potential for Nitrite and N2O Reduction. Frontiers in Microbiology, 9 (2629), pp. 1-13.

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Online at: https://pure.au.dk/portal/files/136209435/fmicb_09_02629.pdf

Summary

Organic agriculture depends on recycling of N to sustain crop production, and the use of catch crops to prevent leaching losses during winter is part of this strategy. The finding in this study, that catch crop residues were a more consistent source of nitrous oxide emissions in spring than synthetic fertiliser, indicates catch crop residue decomposition may contribute negatively to the climate impact of the farming system. Management practices are needed that reduce the potential for denitrification, which is the main source of nitrous oxide. Possible strategies include cultivation to promote aerobic rather than anaerobic degradation, and timing of manure application to avoid that mineral N from manure accumulates during residue decomposition.
Agricultural soils are a significant source of anthropogenic nitrous oxide (N2O) emissions, because of fertilizer application and decomposition of crop residues. We studied interactions between nitrogen (N) amendments and soil conditions in a 2-year field experiment with or without catch crop incorporation before seeding of spring barley, and with or without application of N in the form of digested liquid manure or mineral N fertilizer. Weather conditions, soil inorganic N dynamics, and N2O emissions were monitored during spring, and soil samples were analyzed for abundances of nitrite reduction (nirK and nirS) and N2O reduction genes (nosZ clade I and II), and structure of nitrite- and N2O-reducing communities. Fertilization significantly enhanced soil mineral N accumulation compared to treatments with catch crop residues as the only N source. Nitrous oxide emissions, in contrast, were stimulated in rotations with catch crop residue incorporation, probably as a result of concurrent net N mineralization, and O2 depletion associated with residue degradation in organic hotspots. Emissions of N2O from digested manure were low in both years, while emissions from mineral N fertilizer were nearly absent in the first year, but comparable to emissions from catch crop residues in the second year with higher precipitation and delayed plant N uptake. Higher gene abundances, as well as shifts in community structure, were also observed in the second year, which were significantly correlated to NO− 3 availability. Both the size and structure of the nitrite- and N2O-reducing communities correlated to the difference in N2O emissions between years, while there were no consistent effects of management as represented by catch crops or fertilization. It is concluded that N2O emissions were constrained by environmental, rather than the genetic potential for nitrite and N2O reduction.


EPrint Type:Journal paper
Agrovoc keywords:
LanguageValueURI
Englishcatch cropshttp://aims.fao.org/aos/agrovoc/c_29684
Englishfertilizationhttp://aims.fao.org/aos/agrovoc/c_2863
Englishnitrous oxidehttp://aims.fao.org/aos/agrovoc/c_12838
Englishemissionhttp://aims.fao.org/aos/agrovoc/c_331377
Englishdenitrificationhttp://aims.fao.org/aos/agrovoc/c_15869
Englishgeneshttp://aims.fao.org/aos/agrovoc/c_3214
Englishreductionhttp://aims.fao.org/aos/agrovoc/c_6483
Subjects: Crop husbandry > Crop combinations and interactions
Soil > Soil quality > Soil biology
Soil > Nutrient turnover
Environmental aspects > Air and water emissions
Research affiliation: Denmark > Organic RDD 1 > HighCrop
Denmark > AU - Aarhus University > Faculty of Science and Technology
Denmark > AU - Aarhus University > Faculty of Science and Technology > Department of Agroecology
Denmark > KU - University of Copenhagen
Sweden > Swedish University of Agricultural Sciences (SLU) > Department of Forest Mycology and Pathology
ISSN:1664-302X
DOI:10.3389/fmicb.2018.02629
Deposited By: Rasmussen, Ilse Ankjær
ID Code:36654
Deposited On:04 Nov 2019 14:19
Last Modified:04 Nov 2019 14:19
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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