片沙覆盖的黄土丘陵区土壤水蚀过程研究

Soil Water Erosion Processes in Loess Hilly Gully Region Covered with Sheet Sand

在片沙覆盖的黄土丘陵区，由于恶劣的自然环境及松散的地表组成物质，土壤的水蚀过程明显地不同于典型的黄土丘陵区。通过在神木县六道沟实验基地典型坡段的人工降雨模拟试验，揭示出一些土壤水蚀过程的特殊机理。（１）有片沙覆盖的斜坡小区，径流量少，但径流含沙率大，坡沟的形成过程是：垂直渗流—坡地潜流—崩塌；（２）在沙黄土斜坡小区，每年春末夏初降雨的强度及降雨量是决定坡面产沙量的关键因素；（３）该区坡沟系统的形成发育是风沙沉积、风蚀与水蚀交替作用的结果。

In loess hilly gully region covered by sheet sand,soil water erosion process is different from typical loess hilly gully region because of worse natural environment and loose land surface material. By the tests of artificial simulation of rainfall on typical slope in the Liudao gully experimental area of Shenmu county,the some new and peculiar water erosion processes were observed and described. (1) In the slope with sands,runoff amount is less, and silt content of runoff is more. The gullies are formed by the processes of infiltration interflow collapses. (2) In the slope with sand loess,the major factors of water erosion are the rainfall intensity and rainfall amount of annual first rainfall. (3) In the region,the evolution processes of slope gully system results from alternative actions of sand deposition and water erosion.