Influence of rye cover cropping on denitrification potential and year-round field N 2 O emissions
Cover cropping is beneficial for reducing soil erosion and nutrient losses, but there are conflicting reports on how cover cropping affects emissions of nitrous oxide (N O), a potent greenhouse gas. In this study, we measured N O fluxes over a full year in Illinois corn plots with and without rye co...
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Published in | The Science of the total environment Vol. 765; p. 144295 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Netherlands
15.04.2021
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Subjects | |
Online Access | Get full text |
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Summary: | Cover cropping is beneficial for reducing soil erosion and nutrient losses, but there are conflicting reports on how cover cropping affects emissions of nitrous oxide (N
O), a potent greenhouse gas. In this study, we measured N
O fluxes over a full year in Illinois corn plots with and without rye cover crop. We compared these year-round measurements to N
O emissions predicted by the Intergovernmental Panel on Climate Change (IPCC) Tier 1 equation and the Denitrification-Decomposition (DNDC) model. In addition, we measured potential denitrification and N
O production rates. The field measurements showed typical N
O peaks shortly after fertilizer application, as well as a significant late-winter peak. Cover cropping significantly reduced all peak N
O fluxes, with decreases ranging from 39 to 95%. Neither model was able to accurately predict annual N
O fluxes or the decrease in N
O emissions from cover-cropped fields. In contrast to field measurements, lab assays found that cover cropping significantly increased potential denitrification by 90-127% and potential N
O production by 54-106%. The rye cover-cropped plots had lower soil nitrate and higher soil carbon. When limiting nitrate and excess carbon were provided in lab assays, the proportion of N
O resulting from denitrification decreased. These results suggest that the discrepancy between the observed decrease in field N
O emissions and the increase in denitrification potential may be due to the difference in available nutrients between the field and laboratory measurements. Overall, these results suggest the importance of late-winter peaks in N
O emissions and the potential of rye cover cropping to reduce N
O emissions from agricultural fields. |
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ISSN: | 1879-1026 |