Abstract: Abstract：Field experiments were conducted，and five treatments were set up，including no nitrogen application（T1），conventional nitrogen application rate（T2），20% nitrogen fertilizer reduction combined with humic acid organic fertilizer（T3），20% nitrogen fertilizer reduction combined with seaweed organic fertilizer（T4），and 20% nitrogen fertilizer reduction combined with amino acid organic fertilizer（T5）.The effects of nitrogen fertilizer reduction combined with different functional organic fertilizers on soil nitrogen components，abundance of functional genes related with soil nitrogen cycling，water and nitrogen use，and yield of maize（Zea mays L.）were studied，so as to provide the basis for formulating technical plan of reducing fertilizer and improving efficiency in the maize‐growing region of the North China Plain.The results showed that compared with the T2 treatment，nitrogen fertilizer reduction combined with different functional organic fertilizers decreased the content and proportion of mineral nitrogen at tasseling stage，but increased the proportion of organic nitrogen；increased the content and proportion of mineral nitrogen at mature stage，and the content and proportion of fixing nitrogen of T4 treatment increased.T3 and T4 treatments increased the copy number of functional genes related with soil nitrification and denitrification，and T5 treatment increased the copy number of functional genes（nirK and mosZ）related with soil denitrification.The total nitrogen accumulation of T4 treatment significantly decreased by 20.5% at mature stage.The nitrogen harvest indexes of T4 and T5 treatments significantly increased by 48.5% and 25.6%.T3 treatment promoted soil moisture migration from deep layers to surface，and improved the instantaneous water use efficiency of leaves at tasseling stage；the soil moisture of T4 and T5 treatments decreased at tasseling stage，increased in shallow soil and decreased in deep soil at mature stage. Instantaneous water use efficiency of leaves and water use efficiency of grains of T4 treatment significantly increased，and water use efficiency of grains of T5 treatment significantly increased. The yield of T4 treatment significantly increased，which mainly attributed to the increase of ears number and grains number per row，but T3 treatment significantly decreased，and T5 treatment had no significant change. In summy，under the conditions of this experiment，compared with the T2 treatment，T4 and T5 treatments can significantly increase the nitrogen harvest index and water use efficiency of grains of maize，T3 and T4 treatments can significantly enhance the instantaneous water use efficiency of leaves at tasseling stage，especially T4 treatment，and T4 treatment can also significantly increase the yield，achieving reduction of cost and improvement of efficiency.

Key words: Nitrogen fertilizer reduction, Functional organic fertilizer, Maize（Zea mays L.）, Soil nitrogen components, Functional genes related with soil nitrogen cycling, Yield, Water and nitrogen use

摘要： 采用大田试验，设置不施氮（T1）、常规氮肥施用量（T2）、氮肥减量20%配施腐植酸有机肥（T3）、氮肥减量20%配施海藻有机肥（T4）、氮肥减量20%配施氨基酸有机肥（T5）5个处理，研究氮肥减量配施不同功能有机肥对土壤氮组分、氮循环功能基因丰度和玉米植株氮素吸收、水分利用及产量的影响，为华北平原玉米种植区制定减肥增效技术方案提供依据。结果表明，与T2处理相比，氮肥减量配施功能有机肥处理虽然玉米抽雄期土壤矿质氮含量及占比降低，但有机态氮含量占比增加；玉米成熟期土壤矿质氮含量及占比均提高，且T4处理固持氮含量及占比均提高。T3和T4处理提高了土壤硝化和反硝化功能基因拷贝数，T5处理提高了反硝化功能基因nirK和mosZ的拷贝数。T4处理玉米成熟期总氮积累量显著下降20.5%。T4和T5处理氮素收获指数分别显著提高48.5%和25.6%。T3处理可促进土壤水分从深层向表层运移，提高抽雄期叶片瞬时水分利用效率；T4和T5处理抽雄期各土层土壤含水率均有所降低，成熟期土壤含水率浅层增加、深层降低，T4处理叶片瞬时水分利用效率和籽粒水分利用效率均显著增加，T5处理籽粒水分利用效率显著增加。T4处理产量显著提高，主要得益于穗数和行粒数的增加，T3处理产量显著降低，T5处理产量无显著变化。综上，该试验条件下，与T2处理相比，T4和T5处理可显著提高玉米氮素收获指数和籽粒水分利用效率，T3和T4处理可显著提高玉米抽雄期叶片瞬时水分利用效率，尤其是T4处理，且T4处理还可显著提高产量，实现节本增效。

关键词: 氮肥减量, 功能有机肥, 玉米, 土壤氮组分, 氮循环功能基因, 产量, 水氮利用