施氮量对冬小麦—夏玉米轮作体系中土壤硝态氮分布和累积的影响

摘要

The 6 year-field experiment was carried out to study the effects of nitrogen application rate on soil nitrate nitrogen distribution, accumulation and crop yield in wheat-maize rotation system. The results showed that the suitable amount of nitrogen fertilizer application of the winter wheat should be about 250 kg/ha to guarantee high yield at piedmont plain of Hebei province. The suitable amount of nitrogen fertilizer application of the corn should be about N 150 kg/ha. From the effect of nitrogen application rate on soil nitrate nitrogen distribution and accumula tion, the nitrogen application rate for lower than 150 kg/ha could basically control soil nitrate nitrogen leaching loss to deep soil, which can reduce groundwater pollution risk caused by soil nitrate nitrogen leaching. From the effect of nitrogen application rate on crop partial productivity, with the increasing of nitrogen amount, the partial productivity of wheat and corn decreased obviously. For the treatment of N 150 kg/ha, the partial productivity of wheat and maize were maximum for 43. 09% and 56. 76% respectively. Considering the effect of nitrogen fertilizer rate on crop yield and soil nitrate leaching risk, nitrogen fertilizer rate for wheat and corn should not exceed 150 kg/ha at piedmont plain of Hebei province.%通过6年田间小区定位试验研究小麦-玉米轮作体系中不同施氮量对土壤硝态氮分布、累积以及作物产量的影响.结果表明:保证河北省山前平原小麦高产的适宜施氮量为250 kg/hm2,玉米高产的适宜施氮量为150kg/hm2.从施氮量对土壤硝态氮的分布和累积特征分析,在小麦-玉米季施氮量均低于150 kg/hm2的处理,基本上能控制土壤硝态氮向深层土壤的淋失,进而能明显降低土壤硝态氮向地下水淋失的风险.从不同施氮量对作物偏生产力的影响来看,随着施氮量的增加,小麦和玉米的偏生产力明显降低,在小麦-玉米轮作体系中施氮量均为150kg/hm2的处理,小麦和玉米的偏生产力最大,分别为43.09％,56.76％.综合考虑施氮量对作物产量以及土壤硝态氮的淋失风险,河北省山前平原小麦、玉米推荐施氮量均不超过150 kg/hm2.