PJB-2019-659
Organic matter regulates soil N2O emission and nitrogen utilization in a wheat-maize rotation system
XIAOXIAO SHU
Abstract
This study was examined the effects of reduced inorganic nitrogen (N) application combined with organic matter on soil nitrus oxide (N2O) emissions, N use (NUE), N balance and economic benefits of winter wheat, summer maize and rotation system in North China Plain. Results showed that the soil N2O emission had significantly positive correlation with soil moisture and N reduction significantly reduced soil N2O emission. In rotation system, the treatment of 60% inorganic N fertilizer of RN with homemade organic substances (RN40%+OMB) resulted in the average N2O emission flux decreased by 38.0%, and cumulative emission significantly decreased by 1.58 kg ha-1 (P=0.05) than the treatment of recommended inorganic N amount based on soil tests and crop demand (RN). In addition, the N production efficiency, agronomic efficiency, and apparent utilization of N fertilizer in the rotation system were significantly increased by 14.6 kg kg-1, 9.7 kg kg-1 and 19.5%, respectively. Moreover, the soil residual and N loss in the RN40%+OMB treatment were reduced by 22.0% and 30.1%.Compared with the treatment of inorganic N application as conventional farmers practice (HAN), RN40%+OMB significantly reduced the N2O emission from the rotation soil by 20.9%, N2O emission intensity decreased significantly by 0.04 g kg-1, and N production efficiency and N agronomic efficiency increased significantly by 11.7 kg kg-1, 6.7 kg kg-1, N fertilizer utilization rate increased by 15.3 percentage points, soil residual and apparent loss N decreased by 23.3% and 18.0%, respectively. These results suggested that the treatment of RN40%+OMB is a recommended mode of N regulation of winter wheat/summer maize due to the lowest N fertilizer input and the highest grain yield in North China.
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