s: Fixed site observations for 14 yr long term investigation on the soil water losses in the sloping red earth (slope
8°-15°) showed that soil water losses were closely
correlated with land slope and
vegetative coverage. Runoff rate in sloping red earth could be reduced duplicately by exploitation, while the soil erosion was enhanced duplicately during the first 2 years after exploitation. Subsequently, it tended to be stable. Soil erosion was highly positively correlated with land slope, i.e. soil erosion was increased by 120 t·km -2 per year with a slope increase of 1°. On the contrary, soil erosion was highly negatively correlated with vegetative cove rage, i.e. soil erosion was limited to below 200 t·km -2 per year as the vegetative coverage exceeded 60%. Furthermore, soil erosion was highly related with planting patterns, i.e. soil erosion in contour cropping pattern would be one sixth of that in straight cropping. Based on the view of soil nutrient balance and test data, it was suggested that soil loss tolerance in Q 2 red clay derived red earth should be lower than 300 t·km -2 per year.