氨氧化作为硝化作用的限速步骤，在土壤氮素转化、作物氮素利用过程中发挥重要作用。明确秸秆还田配施氮肥对氨氧化微生物的影响及其与玉米产量的关系，可为秸秆高效还田、减少化肥投入的绿色农业发展提供理论依据。研究设置了秸秆不还田且不施N(S0)、秸秆半量(7.5 t/hm2)还田且不施N(S1/2)、秸秆全量(15.0 t/hm2)还田且不施N(S1)、无秸秆还田配施N 200 kg/hm2(S0N)、秸秆半量(7.5 t/hm2)还田配施N 200 kg/hm2(S1/2N)、秸秆全量(15.0 t/hm2)还田配施N 200 kg/hm2(S1N)等6个处理，探究不同秸秆还田量和N施用量对玉米产量、土壤氮素含量以及土壤氨氧化古菌(AOA)和氨氧化细菌(AOB)丰度和群落结构的影响。结果表明，秸秆还田处理玉米籽粒产量较无秸秆还田有所降低，产量降低主要与穗粒数减少有关；秸秆还田配施氮肥可显著提高玉米籽粒产量和土壤氮素含量。同时可看出，秸秆还田可显著提高AOA-amoA基因拷贝数和群落Shannon指数，但会降低AOB群落Shannon指数；施氮则提高了AOB-amoA基因丰度，且增加了以亚硝化螺菌属(Nitrosospira)和亚硝化单胞菌属(Nitrosomonas)为代表的氨氧化细菌相对丰度；其中AOB-amoA基因拷贝数与玉米产量相关程度最高(r=0.55，P < 0.05)。综上认为，AOA和AOB丰度和群落结构对秸秆和氮肥响应方式不同，二者配合显著增加土壤氨氧化微生物，有利于玉米产量提高。

Amonia oxidation as a rate-limiting step in nitrification, plays an important role in soil nitrogen transformation and crop nitrogen utilization. Clarifying the effects of straw returning with nitrogen fertilizer on ammonia-oxidizing microorganisms and their relationship with maize yield could provide a theoretical basis for the development of green agriculture with efficient straw returning and reduced fertilizer input. Therefore, a field experiment was conducted with 6 treatments: no straw returning and no nitrogen fertilizer (S0), half straw returning (7.5 t/ha) without nitrogen fertilizer (S1/2), full straw returning (15.0 t/ha) without nitrogen fertilizer(S1), no straw returning with 200 kg/ha nitrogen(S0N), half straw returning with 200 kg/ha nitrogen(S1/2N), and full straw returning with 200 kg/ha nitrogen (S1N). The study aimed to explore the impact of different amount of straw returns and nitrogen rates on maize yield, soil nitrogen content, and the abundance and community structure of soil ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB). The findings obtained as follows: the straw return treatment reduced maize grain yield and the yield reduction was mainly related to a reduction in the number of grains in the spike. Straw returning significantly increased AOA-amoA gene copy number and community Shannon index. However, it reduced the Shannon index of the AOB community. Nitrogen fertilizer application increased AOB-amoA gene abundance and increased the relative abundance of ammonia-oxidizing bacteria represented by the genera Nitrosospira and Nitrosomonas. The AOB-amoA gene copy number showed the highest correlation with maize yield (r = 0.55, P < 0.05). In conclusion, the abundance and community structure of AOA and AOB respond differently to straw and nitrogen input, and their combination significantly enhances soil ammonia-oxidizing microorganisms, thereby promoting maize yield.

S513；S147.2

国家重点研发计划(2023YFD2301703)；国家现代农业产业技术体系(CARS-02-19)；国家自然科学基金(U23A 6001-01)。