不同施肥制度下紫色土坡耕地氮素流失特征

Nitrogen Loss from Slope Cropland of Purple Soil under Different Fertilization

利用野外径流小区试验,比较了川中紫色土丘陵区12种不同施肥制度下坡耕地侵蚀产沙特征和氮素迁移特征。结果表明,在单次降雨量达到44 mm时,相对于不施肥而言,农家肥配施化肥分别降低坡地径流与侵蚀量68.2%,67.3%,秸秆还田配施化肥分别降低80.3%,92.6%。不同施肥制度下随地表径流迁移的颗粒态氮占总氮的比例大部分都在60.0%以上。坡耕地平衡施肥能降低坡耕地土壤氮素随径流的损失,增施了磷、钾肥后,总氮迁移量分别降低了41.0%和46.1%。与不施肥相比较,农家肥配施化肥减少径流总氮69.0%,秸秆还田配施化肥减少90.5%。

Field runoff plots experiments were performed to monitor runoff, sediment yield and nitrogen loss in slope cropland of purple soil. Results showed that, Fertilization could reduce runoff and sediment yield of slope cropland. Application of manure with chemical fertilizer could reduce 68.2 %, 67.3 % of runoff and sediment yield. Straw returned with chemical fertilizer could reduce 80. 3%, 92. 6%. Particle nitrogen transport following runoff is the main pathway in slope cropland of purple soil because yield of particle nitrogen was above of 60. 0% of total nitrogen. Balanced fertilization can reduce the nitrogen loss significantly through runoff in slope cropland. Application of N with P and K fertilizer could reduce 41.0% and 46.1% of total N compared with single N fertilizer application. Single chemical fertilizer could reduce 36.5 % of total nitrogen. And manure with chemical fertilizer could reduce 69.0% of total nitrogen. Straw returned with chemical fertilizer could reduce 90. 5% of total nitrogen. So that rational fertilization system could reduce the nitrogen loss from slope cropland. And straw returning has the best effect.