Soil Erosion of Young Forest Stands at the Slow-Slop Land and the Vegetation Coverage

摘要

In order to investigate water and soil erosion in young forest stand which was established on slow-slop land, and to find out the effects of vegetation coverage on soil and water erosion-control, methods as location investigating through setting up 1 000 m~2 runoff plot, combined with simulating rainfalls, were used to calculate and study the affects of vegetation coverage and biological ridge on soil erosion under the young chestnut stand. The results showed: (1) When the annual precipitation was up to 1 638.2 mm, the annual erosion of read soil on slow-slop land without vegetation coverage was 6.4778 ton per 1 000 m~2. (2) When rapes and peanuts were companion cropped successively and the rate of vegetation coverage area was of 24.2%, 31.5%, 44.9%, and 58.4% respectively under the forest stand, the annual soil erosion was reduced by 35.4%-57.55%, the runoff coefficient was decreased by 9.04%, and sediment discharge averagely reduced by 40.02%. With every 10% increase of crop coverage, the sediment discharge rate was decreased by 0.0019-0.0027. (3) The biological ridge within the agro-forest area can reduce the sediment discharge significantly, compared with the control ridge(barren ridge); sediment discharge was decreased 17.02% with ridge of Lalanggrass (Imperata cylindrical). So in south China, to inter-plant or plant peanuts and rapes successively and to setup biological ridge with orange daylily and lalanggrass, are the good biological ways to prevent the soil erosion in the young forest stands at the slow slops.