The Effect of Soil Erosion on Rock Fragment Content in Beijing Hilly Area

摘要

Since soil loss varies with the different land use. It leads to problem of different rock fragment content in top layer in the Beijing hilly area. In this paper, The data of cropland plot, the fallow plot and the wasteland plot at Miyun county, Beijing were used. The topsoil samples and section samples were taken at the upper slope, middle slope and lower slope of the plots. The soil samples were sieved. Then the rock fragment, whose diameter is over 2mm in the sample, was weighted. The percentage of rock fragment in the sample was calculated. The results show that the percentage of rock fragment at fallow plot is the largest and the percentage of rock fragment at wasteland is the smallest. The percentage of rock fragment in the sample of the waste land was known as a normal value, and the soil texture index was expressed with the ratio of the percentage of rock fragment at other land use to the one at waste land. The indexes of fallow land, conventional tillage and wasteland were 2.96, 2.07 and 1, respectively. The results can be applied for land use plan and soil degradation evaluation.