江淮丘陵区塘坝灌溉能力估算及其演变特征

目的探究氮素调控对江淮丘陵地区冬小麦—夏玉米一年两熟(麦玉两熟) N₂O排放及产量的影响，为该地区小麦和玉米稳产减排提供理论依据。方法以江淮丘陵地区麦玉两熟为研究对象，设置不施氮肥(CK)、常规施氮(CN)、生物炭与氮肥配施(SN)、硝化抑制剂与氮肥配施(XN)和叶面喷肥(PN) 5个处理，采用静态箱—气相色谱法，分析不同氮素调控措施下土壤N₂O排放和作物产量变化。结果土壤N₂O排放呈季节性变化，主要集中在施肥和降雨后的15 d内，玉米季是排放高峰期。与CN处理相比，小麦季XN和SN处理的N₂O累积排放量分别显著降低46.07%和25.10%，玉米季XN、SN和PN处理的N₂O累积排放量分别显著降低70.70%、64.01%和9.87%。从周年排放看， XN和SN处理的N₂O累积排放量比CN处理分别显著降低59.36%和46.21%，PN与CN处理间无显著差异。与CN处理相比，XN和SN处理的作物周年产量分别显著增加13.35%和11.27%，N₂O排放系数分别显著降低59.50%和46.28%。结论综合考虑N₂O排放和作物产量，硝化抑制剂与氮肥配施可作为江淮丘陵地区麦玉两熟稳产减排的最佳氮肥调控措施。

A 4-year field measurement of N2O emissions from a maize-wheat rotation system as influenced by partial organic substitution for synthetic fertilizer

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.