【摘要】 <正> 我国黄土高原的水土流失,举世瞩目。据调查估计,黄河年输沙量16亿吨,约有8亿吨来自坡耕地。按耕层20厘米推算,相当于每年损失500多万亩耕地。榆林地区平均每年每平方公里土壤侵蚀11,700吨,年侵蚀总量可达5.1亿吨。强烈的水土流失,不仅严重地破坏了土地资源和生态环境,造成了当地的贫困与落后,而且大量泥沙输入黄河,造成淤积严重,河床升高,导致了历史上多次决口改道,使下游人民的生命财产遭受巨大损失。更多还原

【Abstract】 Soil in loess plateau is extremely deep and has a high capacity of retaining water. Soil erosion in this area is produced not because rainfall exceeds the capacity of soil retaining, but because precipitation intensity exceeds infiltration rate, causing run off on the surface of the soil. Increasing penetration of soil water will decrease or even eliminate run off. Based on this idea, a ground-hole method was proposed and examined to control soil erosion. Simulation and field experiments showed that:1, The ground-hole method had considerable potential to control soil erosion. On yellow loamy soil with a slope of 20 degrees a 1 m deep hole with a diameter of 10 cm per square meter on average might decrease run off by more than 82% and soil sedement by more than 97% in general storm.2. The ground-hole method was able to keep soil and reserve water, suitably to raise soil fertility and to improve water status of soil, and thus to raise crop yields. In loess plateau area, slope land covers more than 70% of total cultivated land, and therefore amendment of slope land is more important. The ground-hole method provides a new way of eontrolling soil erosion, which can make top soil not leave the slope and water not run away out of the land. with increase of yield per unit by this method, it will be possible to leave some land for forestry and for growing grass, and also for establish ing good ecologic system. This in turn will completely control soil erosion.3、The ground-hole method was simple and easy to practise. It was able to get benefit in a short time and cost a little. In addition,it was easy to encourage people to use.更多还原