研究连续3 a秸秆过腹还田和直接还田配施氮肥对农田小麦-玉米周年产量和土壤理化性质的影响，以期为秸秆的高效利用和氮肥的合理配施提供理论参考。结果表明，秸秆过腹还田处理（施入干牛粪4 000 kg/hm²）小麦-玉米周年产量高于周年秸秆均直接还田的N₁（不施氮肥）、N₈处理（秸秆直接还田周年施氮695 kg/hm²），以N₂处理（前茬玉米秸秆过腹还田配施氮695 kg/hm²）周年产量最高，其次是N₃（前茬玉米秸秆过腹还田配施氮653 kg/hm²）、N₄处理（前茬玉米秸秆过腹还田配施氮625 kg/hm²）；秸秆过腹还田条件下，小麦成熟期的N₄处理、玉米成熟期的N₇处理（前茬小麦秸秆过腹还田配施氮695 kg/hm²）对0～20 cm表层土壤有机质、全氮含量提升显著高于N₈处理；秸秆过腹还田处理降低了放线菌相对丰度，增加了变形菌相对丰度。综合来看， N₄处理周年产量较高，虽然略低于N₂处理，但较N₂处理减施氮70 kg/hm²，且N₄处理表层土壤有机质、氮含量最高，对土壤容重、孔隙度的改善效果较好，均优于N₂处理。因此，N₄处理为本研究条件下的最佳处理。

The effects of straw returned to field directly and through cow’s belly combined application of nitrogen fertilizer for 3 years on annual yield of wheat and maize and soil physical and chemical properties were studied, so as to to provide theoretical reference for efficient utilization of straw and rational application of nitrogen fertilizer.The results showed that the annual yield of wheat and maize of the treatment with straw returned to the field through cow’s belly(applying dry cow drug 4 000 kg/ha) was higher than that of the N₁ treatment without nitrogen fertilizer and N8 treatments with 695 kg/ha nitrogen per year when the straw was directly returned to the field,and the N₂ treatment with maize straw returned to the field and 695 kg/ha nitrogen had the highest annual yield of wheat and maize,followed by N₃ treatment with maize straw returned to the field and 653 kg/ha nitrogen and N₄ treatment with maize straw returned to the field and 625 kg/ha nitrogen.Under the condition of returning straw to the field through cow’s belly,the N₄ treatment at the mature stage of wheat and the N₇ treatment with wheat straw returned to the field and 625 kg/ha nitrogen at the mature period of maize had significantly increase of organic matter and total nitrogen contents in the 0—20 cm soil compared with N8 treatment.The treatment with straw returned to the field reduced the relative abundance of Actinomycetes and increased the relative abundance of Proteobacteria.Taken together,N₄ treatment had higher annual yield,although it was slightly lower than that of N₂ treatment,but the nitrogen application decreased by 70 kg/ha compared with N₂ treatment,the surface soil organic matter and nitrogen contents of N₄ treatment were the highest,and the improvement effect of N₄ treatment on soil bulk density and porosity was better,which was better than N₂ treatment.Therefore,N4 treatment was the best treatment under the conditions of this study.