Soils
Yellow loessial soil and cultivated loessial soil is widely distributed in this watershed [could you add some information about this watershed, is it measured by the flume? Size?]. The soil depth is up to 30 meters or more. The particle size smaller than 0.25mm amounts to 70-80% but the clay (small than 0.01mm) is just 10%. It is very incompact: the high silt content leads to surface crusting. The soil here has no clear plough pan. The organic matter here is very low about 0.5% by weight in the top 30 cm layer, and the fertility is very low. The total soil porosity is high. The average soil erosion rate of this region is amount to 6500 tons per square kilometre annually. The erosion of slope cropland is much higher than the average.
