缓坡梯土幼林林下植被覆盖与水土流失

Erosion and Vegetation Coverage of the Slope and Terrace Soil under Young Forest Stands

为了探讨南方丘陵缓坡梯土上经济林幼林林地的水土流失及植被覆盖的防蚀保土效果 ,采用设立 10 0 0 m2 径流小区定位观测和人工模拟测定相结合的方法 ,测定和研究了植被覆盖和生物地埂模式对板栗幼林林地土壤侵蚀的影响 .结果表明 :(1)在无植被覆盖条件下 ,当年降水量为 163 8.2 mm时 ,丘陵红壤区域开垦的缓坡梯地的年土壤侵蚀量可达 6.48kg/m2 ;(2 )林下间种能很好的削减土壤侵蚀量 ,如当花生、油菜种植面积与林地面积的比分别为 2 4.2 %、3 1.5 %至 44 .9%、5 8.4%时 ,年土壤侵蚀量可减少 3 5 .49%～ 5 7.5 5 % ,径流系数平均减少 9.0 4% ,输沙率平均减少 40 .0 2 % ,作物覆盖率每增加 10 %则输沙率减少 0 .0 0 19～ 0 .0 0 2 7;(3 )农林复合经营区的生物保土埂具有明显的拦截泥沙的作用 ,可减少径流含沙量 17.0 7% ,花生、油菜套种或连种模式及萱草。

In order to investigate the water and soil erosion of the young forest stands established on slop and terrace land and find out the effects of vegetation coverage on the soil and water erosion control, methods as located investigation through setting up a 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 the soil of young chestnut stand land. The results show as follows. 1) When the annual rainfall is up to 1 638.2 mm, the annual erosion of the red soil on slop land without vegetation coverage is 6.477 8 ton per 1 000 m 2. 2) When rapes and peanuts are inter planted or successive planted with exact vegetation area of 24.2%～58.4%, under the forest stands, the annual soil erosion is reduced by 35.4%～57.55%, the runoff coefficient is decreased by 24.09%, and the sediment discharge averagely reduces by 40.02%. With each 0.1 degree of coverage increase, the sediment discharge rate decreases by 0.0019～0.002 7. 3) The biological ridge within the agro forest area can reduce the sediment discharge by 56.1%. Compared with the control ridge, the sediment discharge is decreased 44.06% with the ridge of Lalanggrass (Imperata cylindrical), and decreased 36.6% with orange daylily ridge.