氮肥运筹对小麦-玉米轮作农田无机氮淋失的影响

以冬小麦品种石新616,夏玉米品种浚单20为试验材料,采用田间定位试验和原位淋溶装置的方法,研究了河北省山前平原高产农田不同氮肥措施对冬小麦-夏玉米轮作农田0～100 cm土体中氮素淋失的影响。结果表明:不同施氮处理0～100 cm土层的NO3--N淋溶量和累积量均随施氮量的增加而增大;不同施氮措施对0～100 cm土体中无机氮分布和累积量的影响顺序为OPT+N处理>FP处理>FP-S处理>OPT处理>OPT-N处理>CK,其中OPT处理的小麦和玉米产量显著增加,且小麦和玉米收获后土壤的无机氮累积量明显降低;小麦季硝态氮主要分布在20～40 cm土层,玉米季硝态氮主要分布在表层和深层土体中;过量施氮是造成土壤氮素淋失和累积的主要来源。综合考虑经济效益和生态效益,在秸秆还田条件下,施氮量减少20%的施肥措施(OPT处理)是值得推荐的施氮措施。

Effects of Different Nitrogen Management Strategies on Soil Inorganic Nitrogen Leaching in Wheat-Maize Rotation System

Using winter wheat variety Shixin 616 and summer corn variety Jundan 20 as the materials,the effects of different nitrogen management strategies on inorganic nitrogen leaching in 0-100 cm soil layer were studied by field experiments and in situ leaching device in winter wheat-summer maize rotation system of piedmont high yield farmland of Hebei Province.The results showed that NO3--N leaching and accumulation of different nitrogen fertilizer treatments were increased with the increaseing of nitrogen fertilization in 0-100 cm soil layer.The order of influences of different nitrogen fertilizer treatments on the distribution and cumulative amount of inorganic nitrogen in 0-100 cm soil layer was OPT+N treatment>FP treatment>FP-S treatment>OPT treatment>OPT-N treatment>CK.The yields of wheat and maize were increased significantly and the inorganic nitrogen accumulations of soil after wheat and maize harvest were decreased significantly in the OPT treatment.The nitrate nitrogen mainly existed in 20-40 cm soil layer during wheat season,while in maize season it was appeared mainly in the surface and deep layer.Excessive nitrogen fertilization was the main source of soil nitrogen leaching and accumulation.Considering the economic and ecological benefits,the OPT fertilization strategy was worth to be recommended to farmers in the straw mulching condition.