[Objectives] Effects of different nitrogen reduction modes on yield of spring maize and soil NO3-N residue in the southern Loess Plateau were discussed,and scientific fertilization suggestions were put forward to instruct local maize fertilization and protect environment.[Methods] A field experiment was conducted in the south of the Loess Plateau for three years.Spring maize was planted with half plastic film mulching in one crop per annum.The experiment consisted of 5 N fertilization treatments,no N application (CK),applying urea N 200 kg/hm2 (Con),applying urea N 160 kg/hm2 (Mod Ⅰ),applying N 160 kg/hm2 of urea plus nitrification inhibitor dicyandiamide (DCD)(Mod Ⅱ),and applying slow-release fertilizer urea formaldehyde (SR) N 160 kg/hm2 (Mod]Ⅲ).The yield of maize,the fertilizer N use efficiency and the soil NO3 residues were investigated.[Results] Compared with conventional N treatment,the grain yields and N uptakes of maize had no significant difference under the three N treatments,with the grain yield difference in range of 0.1-0.5 t/hm2.Compared with the Con,the agronomic efficiencies of fertilizer nitrogen and N partial fertilizer productivities were increased by 20.2％-23.2％ and 21.9％-23.7％,respectively.The accumulated amounts of nitrate nitrogen in 0-200 cm soil profile were decreased by 90.7,97.3 and 100.7 kg/hm2,respectively,with the decrease rates of 44.7％,47.9％ and 49.6％ in turn.[Conclusions] Reducing 20％ of conventional nitrogen input will not affect spring maize yield and N uptake significantly,but improve agronomic efficiency of fertilizer-nitrogen and N partial fertilizer productivity.Under the same nitrogen application rate,adding nitrification inhibitor or applying slow-release fertilizer do not show priorities over urea on nitrate-N residue reduction.%[目的]研究了不同减量施氮模式对黄土高原南部春玉米产量、土壤硝态氮残留的影响,提出科学施肥模式,旨在指导当地玉米施肥、保护环境安全. [方法]在黄土高原南部沟壑区农田连续进行了3年的田间试验,供试作物为春玉米,一年一熟,采用半覆膜种植方式.试验设不施氮(CK);传统施肥模式(Con,施尿素N200 kg/hm2);减氮模式Ⅰ(Mod Ⅰ,施尿素N 160 kg/hm2);减氮模式Ⅱ(ModⅡ,施尿素N 160 kg/hm2和加一定量的硝化抑制剂双氰胺);减氮模式Ⅲ(ModⅢ,施脲甲醛N 160 kg/hm2)5种处理.调查了玉米产量、收获后土壤硝态氮残留和氮素利用率. [结果]三种减量施氮模式较传统施氮模式施氮量减少20％的情况下,玉米产量连续三年无显著变化(P＞0.05),相差0.1～0.5 t/hm2.与Con相比,Mod Ⅰ、ModⅡ、ModⅢ处理的氮肥农学效率及偏生产力分别增加了20.2％～23.2％和21.9％～23.7％,0-200 cm土层NO3-N的残留量分别减少了90.7、97.3、100.7 kg/hm2,其降幅依次为44.7％、47.9％、49.6％. [结论]连续三年减少20％的施氮量不影响春玉米产量及吸氮量,可提高氮肥的农学效率和偏生产力,显著减少土壤剖面NO3--N残留量.在同一施氮量下,添加硝化抑制剂或施用缓控释肥对硝态氮残留量减少作用不甚明显.
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