紫色土坡耕地施肥水平对土壤侵蚀及氮磷流失影响

以紫色土坡耕地"冬小麦-夏玉米"种植模式为研究对象,设置对照处理、复合施用农家肥和化肥、单施化肥、单施化肥增加施肥量、单施化肥横坡垄作5种施肥水平,采用径流小区定点监测的方法,研究紫色土坡耕地不同施肥水平下土壤侵蚀特征。结果表明:施肥水平和降雨量对径流量影响极为显著,各施肥水平下次降雨泥沙流失量与降雨量呈线性正相关,单位面积泥沙流失量与径流量在增加施肥时为幂函数关系,其他施肥水平下均为对数函数关系。施肥水平和降雨量对径流中氮磷浓度均具有显著影响。各施肥水平下径流中氮磷流失浓度变化趋势与降雨量变化趋势基本一致,随降雨量增加而增大,不同施肥水平下,氮磷浓度波动范围不同;复合施用农家肥和化肥,径流中氮素及可溶性磷浓度较稳定;各施肥水平下径流中氮磷浓度最高值出现与暴雨事件出现基本一致,同时追加施肥等农事活动也对磷素浓度最大值具有一定影响。

Effects of Different Fertilization Level on Erosion,Nitrogen and Phosphorus Losses on Sloping Farmland of Purple Soil

Through monitoring the runoff in plots,the soil erosion characteristics and N and P losses were studied under CK,combined application of manure and fertilizer,chemical fertilizer,chemical fertilizer with increasing fertilization,and contour plowing with chemical fertilizer with "winter wheat-summer maize" on the sloping farmland of purple soil.Results were as follows: Effects of fertilization level and rainfall on runoff were quite remarkable,and second rainfall sediment loss was linearly related to rainfall on different fertilization levels.The relation between sediment loss and runoff was power function relation in the unit area with the increase of fertilization,while the relation was logarithmic function in other fertilization levels.Effects of fertilization level and rainfall on nitrogen and phosphorus concentration in runoff were quite remarkable.The varying trend of nitrogen and phosphorus concentration loss in runoff was consistent with the varying trend of rainfall on different fertilization levels.With increase of rainfall,nitrogen and phosphorus concentration fluctuation range were different on different fertilization levels;combing application of manure and fertilizer,nitrogen and soluble phosphorus concentration in runoff were stable;maximum concentrations of nitrogen and phosphorus in runoff was consistent with occurrence of heavy rain on different fertilization levels,while additional fertilizer and other agricultural activities had influences on the maximum phosphorus concentration.