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Sehy, U. ; Ruser, R. ; Munch, J.-C.

Nitrous oxide fluxes from maize fields : Relationship to yield, site-specific fertilization and soil conditions.

Agric. Ecosyst. Environ. 99, 97-111 (2003)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Nitrous oxide emissions and selected soil properties in a high and a low yielding area of a maize field were monitored weekly over a 1-year period. In both the high and the low yielding area, N2O emissions from a treatment subject to site-specific N-fertilization were compared to a conventionally fertilized control. Emission peaks were measured following N fertilization, rainfall, harvest, tillage and freeze-thaw cycles from all treatments in conditions favorable for denitrification. Between 80 and 90% of annual emissions were released between April and September. A value of 60% WFPS was identified as a threshold for the induction of elevated N2O emissions (>50 μg N2O-N m−2 h−1). A significant relationship (r2=0.41) between N2O flux rates and WFPS was found when neither soil nitrate contents nor temperature were limiting for microbial denitrification. Mean cumulative N2O emissions from the control treatments in the high yielding area, located in a footslope position and thus receiving lateral water and nutrient supply, more than doubled those from the control treatments in the low yielding area in a shoulder position (8.7 and 3.9 kg N2O-N ha−1, respectively). Higher average WFPS in the high yielding area was identified as responsible for this difference. The site-specific fertilized treatments in the low yielding area were supplied with 125 kg N fertilizer ha−1 as compared to 150 kg N fertilizer ha−1 (control treatments). This reduction resulted in 34% less N2O released in roughly 10 months following differentiated fertilization while crop yield remained the same. In the high yielding area, N fertilizer supply in the site-specific fertilized treatment was 175 kg N ha−1 as compared to 150 kg N ha−1 in the control. Neither crop yield nor N2O emissions were significantly affected by the different fertilizer rates.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords N2O; Soil moisture; Soil nitrate; N fertilization; Site-specific fertilization; Precision farming
ISSN (print) / ISBN 0167-8809
e-ISSN 1873-2305
Journal Agriculture, Ecosystems & Environment
Quellenangaben Volume: 99, Issue: 1-3, Pages: 97-111 Article Number: , Supplement: ,
Publisher Elsevier
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Soil Ecology (IBOE)