不同降雨强度下紫色土陡坡地侵蚀泥沙养分特征

Characteristics of Sediment Nutrients from Steep Land of Purple Soil Under Different Rainfall Intensities

采用野外人工模拟降雨试验研究雨强对三峡库区紫色土陡坡地侵蚀泥沙养分浓度的影响。结果表明:(1)在整个产流过程中,随着降雨强度的增大,径流携带的侵蚀泥沙量呈增大趋势,侵蚀泥沙全磷、全钾、碱解氮浓度也表现出增大的变化趋势,而侵蚀泥沙全氮、有效磷、速效钾浓度随雨强增大的变化规律不明显。(2)随着降雨强度的增大,侵蚀泥沙量、侵蚀泥沙各养分浓度到达峰值点的时间分别有不同程度的提前,且峰值点值也有不同程度的增加。(3)同一雨强下,随着产流历时的增加,径流泥沙量呈现出先增大后逐渐减小至平稳的变化趋势,侵蚀泥沙全钾、全磷、全氮、碱解氮、有效磷、速效钾浓度也表现出相同的变化特征。(4)不同降雨强度下,侵蚀泥沙携带的全钾、全磷、碱解氮、有效磷、速效钾发生了富集,但各养分的富集程度与雨强无明显的相关关系。

The effects of different rainfall intensities（0.285,0.978,1.737 mm/min） on sediment nutrient concentrations from steep land of purple soil in Three Gorges region were studied by artificial rainfall simulations.Results showed that with the increasing rain intensity,the eroded sediment and the sediment nutrient concentrations,including total phosphorus,total potassium and available nitrogen,all increased throughout the runoff process.However,the concentrations of total nitrogen,available phosphorus and available potassium had no obvious variation.The peak sediment and each peak concentration of sediment nutrients increased in some degree and the time peak values occurred advanced in different degrees respectively.Meanwhile,the quantity of sediment increased first and then gradually reduced,subsequently,remained relatively stable levels under the same rainfall intensity.The concentrations of sediment nutrients which were total potassium,total phosphorus,total nitrogen,available nitrogen,available phosphorus and available potassium had the same variation.All the sediment nutrients enriched except total nitrogen,but the enrichment degree had no obvious relationship with the rainfall intensity.