人工模拟降雨条件下石灰土养分流失规律

Nutrient Loss of Limestone Soil Under Artificial Simulated Rainfall

通过对三峡库区香溪河流域选取具有代表性石灰土坡耕地进行原位人工模拟降雨试验,研究了在不同降雨强度下石灰土中氮磷养分随地表径流的流失规律。结果表明:雨强越大,地表径流量、径流总量、泥沙流失量越大,初始产流时间越短,但是雨强对泥沙流失浓度的影响不显著;不同雨强下TP、TN浓度都随着产流时间的延长逐渐变小,最后趋于平衡,而且雨强越大,TP、TN浓度流失越严重,其中TP主要以PP形式流失,达到80%以上,TN的流失在大雨时PN占优,中雨时以DN占优;地表径流磷素的流失主要以泥沙携带为主,泥沙养分流失浓度与雨强无关,但是泥沙养分流失量却与雨强和泥沙流失量成正比。

Through carrying out a field simulated rainfall experiment on the sloping arable land of typical limestone soil in Xiangxi River basin of Three Gorges reservoir area,we studied the patterns of nitrogen and phosphorus loss in runoff on limestone soil under different rainfall intensities.The results showed that total runoff and sediment yield increased with the increase of rainfall intensity,while the initial runoff-yielding time decreased,and the rain intensity had no significant effect on the loss concentration of sediment.The concentrations of TP and TN became smaller and tended to be stable with the increase of the runoff-yield time under different rainfall intensities,and with the increase of rainfall intensity,the loss of TP and TN increased.PP was the main form of phosphorus loss,which accounted for more than 80%.PN was the main form of nitrogen loss under high rainfall intensity,while DN was the main form under moderate rainfall intensity.The phosphorus loss mainly occurred through sediment carrying,and the nutrient loss concentrations of sediment did not correlate with the rainfall intensity,but the nutrient loss amount of sediment was positively correlated with rainfall intensity and the loss amount of sediment.