Soil humic acid loss is one of the signs of soil degradation.After vegetation removal,the spatial distribution of soil humic acid loss rate responds to types and intensity of soil erosion at the hillslope and gully slope.The most severe location of soil humid acid loss is the ditch of shallow gully erosion area at the middle and lower part of the hillslope,the second one is rill erosion area and the sheet erosion on the upper part of slope is not as severe as the other two.The contents of...