IMPACT OF ACCELERATED EROSION ON DYNAMICS OF SOIL HUMIC ACIDS
加速侵蚀对土壤腐殖酸动态变化的影响

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 soil humic acid,humin acid and fulvic acid in eroded soil are decreased exponentially with reclaimed years and their loss rate is affected by erosion intensity and types.The loss rate of soil humic acids has a close relationship to the soil profile damage by accelerated erosion.Vegetation restoration can make soil humic acids gradually increase,soil fertility be restored and soil degradation process be reversed as a result.