采用田间试验研究不同施氮量对两个玉米品种子粒产量、土壤硝态氮累积量及氮素利用率的影响。结果表明，玉米产量随施氮量增加显著提高，当施氮量高于200 kg/hm²时玉米产量不再增加，高氮处理地上部分秸秆生物量出现下降趋势。0～100 cm土层硝态氮累积量随氮素输入量的增加显著增加。不同玉米品种对氮素的吸收利用影响硝态氮在土壤中的累积，植株氮积累量存在差异。密植型玉米先玉335总吸氮量高于平展型玉米辽单28，土壤硝态氮的累积量也显著低于后者。不同氮肥水平的氮肥利用率为28.38%～35.33%，高氮处理氮肥利用率最低。本试验条件下，中氮处理水平基本能够满足作物生长的需求。综合产量、氮肥利用效率和土壤硝态氮累积情况，确定合理施氮量应控制在200 kg/hm²左右。

Field experiment was carried out to investigate N application on yield, soil nitrate accumulation, plant N uptake and utilization of two kinds of maize. The results showed that maize yield increased significantly with the increment of nitrate application rate, but the biomass of maize decreased and the yield of grain of maize didn’t increase when the nitrogen application rate was higher than 200 kg/ha. Nitrogen application significantly increased nitrate content in all layers of soil profile and hyper-accumulation of nitrate was found in 0-100 cm soil layer in the treatment of 200 kg/ha nitrogen application. There were differences in the yield and plant total amount of N absorption among 2 types of maize. Total amount of N absorption and the content of soil nitrate in the high dose treatment which planted density-tolerance maize Xianyu 335 were higher than density no-tolerance maize Liaodan 28. High nitrogen using efficiency was found in the treatment whose nitrogen fertilizer rate was 200 kg/ha. Under the experimental conditions, with the consideration of yield, nitrogen utilization and soil nitrate accumulation, a reasonable amount of nitrogen application should be controlled at about N 200 kg/ha.

国家水体污染控制与治理科技重大专项（2008ZX07425-004）、“十一五”国家科技支撑计划重点项目（2008BAD95B01）