坡地退耕还林(草)对土壤磷素流失的影响

Effect of Returning Farmland to Forest(Grass) on Phosphorus Runoff of Slope Land

退耕还林（草）能有效的减少坡地土壤磷素的流失,尤其水溶态磷的流失,表现为：在相同的降雨量下,地表径流中颗粒态磷的含量分别减少62.95%和43.79%,磷酸根态磷含量分别减少45.59%和23.53%;通过径流小区试验,表明退耕还林（草）后径流中水溶性磷的流失量分别减少44.81%和60.24%,径流泥沙颗粒态磷的流失量分别减少27.82%和41.94%。

Returning farmland to forest （grass） can effectively reduce the phosphorus loss of slope land, especially dissolved phosphorus. By the experiments of runoff plots without boundary, at the same precipitation, the particulate phosphorus content of runoff is respectively reduced 62.95% and 43.79% and the PO4^3 -P content is respectively reduced 45.59% and 23. 53% after returning farmland to forest （grass）; By the experiments of runoff plots in field, the dissolved phosphorus loss of runoff silt is respectively reduced 44.81% and 60.24 N and the particulate phosphorus loss of runoff silt is respectively reduced 27.82% and 41.94% .