石匣小流域水土保持措施蓄水保土效益试验研究

Benefits from Soil and Water Conservation Measures on Reducing Runoff and Sediments in Shixia Small Watershed

通过石匣小流域径流试验小区的降雨径流泥沙资料,分析不同水土保持措施对径流泥沙的影响,探讨水土保持措施的蓄水保土效益。研究结果表明: ①合适的整地造林措施能有效地拦蓄降雨,减小土壤侵蚀;自然坡的水土流失都较小; ②水平条中土埂可减少径流20%～45%,减少土壤侵蚀31 5%～71 2%; ③水平条与鱼鳞坑的水保效益相当; ④在16°左右坡地采取水保措施(水平条、鱼鳞坑造林)比开荒减少地表径流77 7%～92 1%,在4°左右坡地修梯田比坡耕地减少地表径流54 2%,减少土壤侵蚀67 95%; ⑤水保措施均不同程度地减少了土壤氮、磷流失量,其中大水平条比开荒总氮流失量减少73 65%,总磷流失量减少42 86%;梯田比坡耕地总氮流失量减少60 98%,总磷流失量减少85 29%,说明大水平条和梯田的保水、保土、保肥效益明显。

The Benefits produced by different measures of soil and water conservation on reducing runoff and sediments are analyzed with the data from runoff plots in Shixia Small Watershed. The results are presented as following: 1) Suitable land preparation for afforestation can hold up more precipitation and reduce soil erosion effectively; 2) Narrow terrace can reduce 20%～45% of runoff and 31.5%～71.2% of sediments; 3) The benefits on reducing runoff and sediments from narrow terrace are generally equal from fish-scale pits. 4) On 16° slop area, the runoff would be 77.7%～92.1% reduction in the areas after vegetation measures with narrow terrace and fish-scale pit land preparation from slop farming. On 40 slop area, the runoff would be cut down 54.25% and sediment 67.95% in the areas after terrace from slop farming; 5) The measures also can reduce N and P losses, such as N can reduce by 73.65% and P by 42.86% from narrow terrace area and N by 60.98% and P by 85.29% from terrace area compared with that from slop farming areas.