关键词: 丘陵沟壑区, 陡坡, 微地形, 坡面面积, 黄土高原

Abstract: Soil moisture content is the main factor affecting vegetation conservation and regeneration in the loess hillygully region, but it is low in steep slope. Microrelief affects strongly the soil moisture content in slope. A field measurement of the terrain parameters was carried out with a 3dimentional laser scanning total station in the Hejia Valley in Wuqi County, Shaanxi Province. The distribution of gullies, shallow gullies, platforms, scarps and collapses on steep slope was researched based upon Arc GIS 9.2. The results showed that the proportions of area of microrelieves varied in a range of 18%-30% of the total steep slope area and 23.13% in average. The proportions of area of different microrelieves were in an order of gully (8.44%)>platform (6.66%)>shallow gully (5.00%)>scarp (1.53%)>collapse (1.52%). Exposure and slope were the main topographic factors affecting the proportions of area of gullies, shallow gullies and collapses, the proportion of area of scarp was mainly affected by slope, and there was no obvious effect of exposure and slope on the proportion of area of gentle platform. Exposure affected the proportions of area of microrelieves on steep slope, proportions of the microrelieves were in an order of sunny slope ＞semisunny slope＞semishaded slope＞shaded slope, and the proportions of area of collapse, gully and shallow gully on sunny slope and semisunny slope were higher than those on semishaded slope and shaded slope, however, there was an opposite result for the proportion of area of scarp. The proportions of area of scarp, gully and shallow gully were decreased with the increase of slope, but the proportion of area of collapse was increased with the increase of slope.

Key words: loess hillygully region, steep slope, microrelief, slope area, Loess Plateau