水土保持措施对径流泥沙及养分流失的影响

以北京市门头沟区龙凤岭水土保持科技示范园为研究对象,对2005—2009年汛期(5—11月)径流小区的径流量、侵蚀产沙量及养分流失量进行了分析。结果是:同为10 m坡长的径流小区,其径流量和养分流失量从大到小依次为裸地、坡耕地和石坎梯田,产沙量最大的是裸地,其次是石坎梯田,最小的是坡耕地;与裸地小区相比,10 m坡长的水土保持措施小区可减少全氮流失量50.5%~91.4%、减少全磷流失量31.8%~75.8%;20 m坡长裸地径流小区的径流量、泥沙量和养分流失量均明显大于鱼鳞坑,鱼鳞坑小区可减少径流量68.4%~83.0%、减少产沙量71.1%~82.7%、减少全氮流失量64.4%~74.9%、减少全磷流失量40.6%~87.3%。说明水土保持措施具有良好的保持水土和减少养分流失的作用。

Influence of Soil and Water Conservation Measures to Runoff Sediment and Nutrient Loss

The paper analyzes the runoff depth,sediment yield of soil erosion and nutrient loss of runoff plot in flood season(from May to November) from 2005 to 2009 by taking Longfengling scientific demonstration garden of soil and water conservation in Mentougou District of Beijing as a study object.The outcomes show that a) the sequence of runoff depth and nutrient loss of runoff plots with 10 m long slope from big to small are uncovered land,sloped land and terraced field with stone ridge,and the maximum sediment yield is uncovered land,then terraced field with stone ridge and sloped land is the minimum;b) comparing with the plot of uncovered land,the 10 m long slope in the plot with soil and water conservation measures can reduce total nitrogen loss by 50.5%~91.4% and total phosphorus loss by 31.8%~75.8%;c) the runoff depth,sediment and nutrient loss of runoff plots with 20 m long slope in uncovered land are obviously greater than that of the plots with piezoglypt.The plot with piezoglypt can reduce runoff depth by 68.4%~83.0%,sediment yield by 71.1%~82.7%,total nitrogen loss by 64.4%~74.9% and total phosphorus loss by 40.6%~87.3%.It shows that soil and water conservation measures have fairly good function on soil and water conservation and nutrient loss reduction.