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土连续两年小麦—玉米轮作条件下 ,播前一次施氮量 130～ 5 2 0kghm-2 a-1时 ,氮肥用量对硝态氮在土体中的移动深度没有影响 ,但土壤剖面中残留的硝态氮量随施氮量增加显著增加。播前一次施用氮肥 ,差减法计算的肥料氮表观回收率 (作物携出量和土壤硝态氮的残留量 )为 6 2 %～ 82 7% ;就作物而言小麦的携出率高于玉米 ,在玉米生长季节有更多的硝态氮可能被淋移至土壤剖面的下层。小麦—玉米轮作一年 ,不同的施氮时间对肥料氮的表观回收率以及硝态氮在土壤剖面中的分布、累计没有明显影响。土区合适的氮肥用量是控制硝态氮向深层移动的主要措施
When soil nitrogen was 130 ~ 520kghm-2 a-1, the nitrogen application had no effect on the depth of nitrate-N movement in soil under wheat-corn rotation for two consecutive years. However, in the soil profile The residual nitrate nitrogen increased with the increase of nitrogen application. The apparent recovery of fertilizer N (sowing amount of crop and the residual amount of nitrate in soil) calculated by subtraction method was the highest at sowing time of 62% ~ 82 7% Corn, with more nitrate during the corn growing season, may be leached to the bottom of the soil profile. Wheat-corn rotation for one year, different nitrogen application time on the apparent recovery of fertilizer nitrogen and nitrate nitrogen distribution in the soil profile, the cumulative no significant impact. soil suitable amount of nitrogen fertilizer is to control the deep movement of nitrate nitrogen to the main measures