PurposeTo explore the effects of nitrogen regulation on N2O emission and yield of wheat-maize double cropping system in Jianghuai hilly region, so as to provide a theoretical basis for stable yield and emission reduction of wheat and maize in this area.
MethodsTaking wheat-maize double cropping system of Jianghuai hilly region as the research object, five treatments including no nitrogen fertilizer (CK), conventional nitrogen application (CN), combined application of biochar with nitrogen (SN), combined application of nitrification inhibitor with nitrogen (XN) and foliar topdressing (PN) were set. The changes of soil N2O emissions and crop yield in different nitrogen control measures were analyzed by static box-gas chromatography.
ResultsThe soil N2O emissions showed seasonal changes, and N2O emissions were mainly concentrated within 15 days after fertilization and rainfall, and the maize season was the peak of emissions. Compared with CN treatment, the cumulative N2O emission of XN and SN treatments in wheat season decreased significantly by 46.07% and 25.10%, respectively, and the cumulative N2O emissions of XN, SN and PN treatments in maize season decreased significantly by 70.70%, 64.01% and 9.87%, respectively. In terms of annual emissions, the cumulative N2O emissions of XN and SN treatments were significantly lower than that of CN treatment by 59.36% and 46.21%, respectively, and there was no significant difference between PN and CN treatments. Compared with CN treatment, the annual crop yield of XN and SN treatments increased significantly by 13.35% and 11.27%, respectively, and the N2O emission coefficient decreased significantly by 59.50% and 46.28%, respectively.
ConclusionConsidering N2O emission and crop yield, combined application of nitrification inhibitor with nitrogen can be used as the best nitrogen regulation measure for stable yield and emission reduction of wheat-maize double cropping system in Jianghuai hilly region.
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