自然降雨对紫色土坡耕地氮磷流失的影响

Influence of Nature Rainfall on Nitrogen and Phosphor Loss in Slope Land of Purple Soil

在三峡库区主要土壤类型(紫色土)、不同坡度(15°、25°)、不同种植模式(柑桔-牧草、蔬菜-马铃薯、玉米-小麦)上建立径流池,研究自然降雨条件下土壤氮磷流失特点。结果表明,土壤氮、磷流失量和流失率在降雨量增加到一定程度时即达最大值,继续增加降雨量,氮、磷流失量和流失率呈下降趋势。氮、磷流失量和流失率同72h内降雨量呈S曲线关系。径流水中总氮(磷)量和浓度同坡度和种植模式无显著性差异。径流水中总氮(磷)浓度随降雨量增加无明显增加趋势,径流水中总氮流失量随降雨量的增加也无明显增加趋势,但径流水中总磷流失量随降雨量的增加呈直线增加。

The experiment was conducted in main soil type（purple soil）,different slopes（15°,25°）,and different planting patterns（orange-weed,vegetable-potato,corn-wheat）.The results showed that runoff ratio and loss amount of nitrogen and phosphor in soil arrived biggest along with rainfall addition.When rainfall was continuous addition,the runoff ratio and loss amount of nitrogen and phosphor appeared downtrend.The runoff ratio and loss amount of nitrogen and phosphor had line relationship with rainfall in 72 hour,this relation had statistic significance.The concentration and loss amount of nitrogen and phosphor in runoff water had not obvious difference between slopes,and they were so among planting patterns too.The concentration of total nitrogen and total phosphor in runoff water had not obvious addition along with rainfall addition,and the loss amount of total nitrogen in runoff water was so too,but the loss amount of total phosphor in runoff water had obvious linear addition along with rainfall addition.