降雨强度对紫色土坡耕地养分流失的影响

Effect of Rain Intensity on Nutrient Losses from Sloping Land of Purple Soil

采用人工模拟降雨装置,通过野外径流小区试验,研究了不同雨强对紫色土净作玉米条件下坡耕地土壤氮、磷、钾养分流失的影响。结果表明,在小雨强条件下,无地表径流及土壤侵蚀发生;随着雨强的增大,地表径流量、径流总量及土壤侵蚀量都急剧增加。磷素和钾素流失总量也随着雨强的增加而增加,而雨强对氮素流失的影响不大。在3种雨强条件下,氮素均主要通过地下径流的途径而流失,平均占氮素总流失量的96.5%。在小雨强条件下,磷、钾素不通过地表径流和泥沙流失;在中、大雨强条件下,磷、钾素流失途径均以侵蚀泥沙流失为主,分别平均占流失总量的95.3%,93.0%。

Experiments of field runoff plots, which were conducted in corn sloping plots, were designed to assess the effects of different rainfall intensities（0. 972,1. 741,2. 255 mm/min）on soil nitrogen, phosphorus, potassium loss from a purple soil by artificial rainfall simulations. Results showed that there was no surface runoff and soil erosion occurred at low rain intensity. As rain intensity increased, the amount of surface run- off, total runoff and sediment increased sharply, so as losses of P and K. Rain intensity had little influence a- mount of N lost. With three types of rain intensities, N loss mainly went through the underground runoff and that account for 96.5% of loss N. With small rain intensities, P, K did＇t loss through surface runoff and soil erosion. With middle and heavy rain intensities, P, K loss mainly went through the soil erosion, which account for 95.3%, 93.0% of lost P, K respectively.