依托黑土长期定位施肥试验平台,采集不同施肥处理0-300 cm土壤剖面样品(按每20 cm一层分开),测定土壤硝态氮含量,并结合产量计算氮素利用效率。结果表明：长期施肥显著提高籽粒产量,以NPKM处理产量最高,为11414 kg/hm₂^,较NPK提高了8.7%。与NPK处理相比,NPKS产量无显著差异,而N、NP籽粒产量分别下降44.6% 和9.5%,达显著水平。施肥显著增加地上部总吸氮量、氮收获指数。NPKM处理氮收获指数显著高于NPK。综合氮素利用率以及氮素贡献率,NPKM处理优于所有施肥处理。NPKM处理氮素贡献率最高,达73.2%,偏施肥降低土壤氮素贡献率以及氮素利用率。各处理硝态氮含量随着土层的加深均呈先降低后升高的趋势。硝态氮在土体中有下移趋势,偏施肥硝态氮向深土层迁移量较大,其次是有机替代处理。硝态氮主要积累在0-100 cm土层,NPK、NPKM处理硝态氮积累量占比高于55%。200-300 cm土层N、NP处理硝态氮积累量较高,增加硝态氮淋溶风险；NPK、NPKM处理硝态氮积累量较低,淋溶风险降低。因此,有机肥替代部分化肥可显著提高玉米籽粒产量,增加氮素利用效率,减少深层土体中氮素积累,降低氮素淋溶风险,实现高产高效。

Based on a long- term fertilizer experiment in black soil, soil nitrate nitrogen content was analyzed for every 20 cm depth of soil till 300 cm under different fertilizer treatments, and nitrogen use efficiency was calculated based on the yield. The results showed that long-term fertilization significantly increased grain yield, and NPKM treatment had the highest yield (11414 kg/hm2), which was 8.7% higher than NPK. Compared with NPK, NPKS had no significant difference, while N and NP decreased by 44.6% and 9.5%, respectively, reaching a significant level. Fertilization significantly increased total N uptake and N harvest index. Compared with NPK, NPKM significantly increased N harvest index. Synthesized N use efficiency and N contribution rate, NPKM was superior to all fertilizer treatments. Its N contribution rate reached 73.2%, partial fertilizer treatments reduced N contribution rate and N use efficiency. In all treatments nitrate nitrogen content decreased first and then increased with the deepening of soil layer. Nitrate nitrogen had a downward trend in soil profile, and nitrate nitrogen migrated to deep soil layer in partial fertilizer treatments, followed by organic replacement treatment. Nitrate nitrogen mainly accumulated in 0-100 cm soil layer, and the proportion of nitrate nitrogen accumulation was higher than 55% under NPK and NPKM treatments. N and NP treatments had higher nitrate accumulation in 200-300 cm soil layer, which increased the risk of nitrate leaching. NPK and NPKM treatments had lower nitrate accumulation and lower leaching risk. Therefore, organic fertilizer N replaced part of chemical fertilizer N can significantly improve maize grain yield, increase N use efficiency, reduce N accumulation in deep soil and N leaching risk, achieve high yield and high efficiency.

农业农村部“科研设施专项运行维护费”(G2022-07-2)资助。