不同坡度径流小区产流产沙监测结果初报

相同土壤在同一降雨条件下，影响土壤侵蚀的因素是地形及植被。用粮农组织推荐的径流小区观测方法，经过2年对不同坡度上同一耕作方法和同一作物的侵蚀测定表明:10°～24°之间随坡度增大土壤侵蚀量增加，24°～35°之间随坡度增加土壤侵蚀增加趋势不大；径流系数也有同样反映。洋芋是陕北的主要作物，但洋芋作物地中的水土流失量大于其它作物地，甚至在陡坡26°时大于对照裸地。水平沟耕作栽培是一种有效治理措施，它在微地形上改变了地面坡度及坡长，有明显的截流保持水土效益，2年试验结果比坡地传统耕作减少土壤流失量60.3%。

Report on the Measurement of Runoff Plots With Different Slopes

Under the same soils and rainfall, the topography, vegetation and cultivation practice effect the soil erosion. The runoff and sediment yield of crop land with different slopes have been measured in hilled and gully areas since 1983. The results show that runoff and sediment yield increased with the slopes between 10 and 24 degrees,and decreased with the slopes between 24 and 35 degrees. Potato is one of the main crops in Northern Shaanxi, but to plant it caused more soil erosion compared with other crops. Contour may change the degrees and length of slope and increasing roughness of micro-topography and reduced 60.3 percent of soil erosion compare with traditional cultivation of potato on the slope land.