北京地区等高草篱防治坡耕地水土及氮磷流失效果研究

Effects of Contour Grass Hedges on Soil,Water and N,P Nutrients Loss on Sloping Croplands in Beijing

在北京地区自然降雨条件下,研究了狼尾草和野古草两种等高草篱在不同坡度(5%,10%,15%,20%)下对裸露坡耕地水土及氮磷养分流失的影响。研究结果表明,两种草篱均可显著减少径流和土壤流失,并同时显著减少随径流和泥沙的氮磷养分流失,且两种草篱对水土及氮磷流失的防治效果随坡度增加而逐渐减弱。其中,狼尾草草篱对水土及氮磷流失的防治效果显著好于野古草草篱。与无草篱相比,狼尾草可分别减少73%的地表径流和86%的土壤流失,同时减少76%的氮流失和88%的磷流失;与此对应,野古草可减少54%的地表径流和64%的土壤流失,以及55%的氮流失和63%的磷流失。另外,径流量和土壤流失量是影响氮磷养分流失的主要因素。

The decreasing effects of Pennisetum（Pennisetum alopecuroides（Linn.） Spreng.） and Arundinella（Arundinella hirta（Thunb.） C.Tanaka） grass hedges on the loss of soil,water and N,P nutrients were studied under natural rainfall on fallow lands with different slope gradients（5%,10%,15%,20%）.The results showed that the loss of runoff and sediments and N,P nutrients were significantly reduced by Arundinella and Pennisetum hedges.These reducing effects of two grass hedge gradually decreased with the increase of slope gradient.In addition,the Pennisetum hedges was much more effective than Arundinella hedges in the controlling of soil,water and N,P nutrients loss on sloping croplands.As compared to the plots without grass hedges,the runoff and sediments on plots with Pennisetum hedges were decreased by 73% and 86% respectively,and the nitrogen and phosphorus loss were decreased by 76% and 88% respectively;Correspondingly,the runoff and soil loss on plots with Arundinella grass hedges were decreased by 54% and 64% respectively,and the nitrogen and phosphorus loss were decreased by 55% and 63% respectively.Finally,the results indicate that the runoff and soil loss were the dominant factors in the controlling of nutrients loss on sloping croplands.