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黄土高原水土流失面积占黄土高原总面积的90%,其中侵蚀模数在5000吨以上的水土流失严重地区占一半以上。这些严重地区基本上属于半干旱地区,年降水量300—500毫米左右。仅就数量上看,发展旱作农业是可行的。但由于大量水土流失及降水的年内和年际分配不均,变化悬殊,造成本地区农业生产长期低而不稳。在这种情况下,尽力挖掘水源,发展小型水利灌溉无疑是克服干旱,获得较好收成的最重要手段。实践证明,本地区旱地变水地后,结合土壤培肥,产量可提高数倍以至十倍以上;但是,目前
Soil erosion in the Loess Plateau accounts for 90% of the total area of the Loess Plateau, with more than half of the areas suffering from soil erosion with erosion modulus above 5000 tons. These serious areas are basically semi-arid areas with an annual precipitation of about 300-500 mm. Only quantitatively speaking, the development of dry farming is feasible. However, due to the large amount of soil and water loss and uneven distribution of annual and inter-annual precipitation, the disparity between them has caused the long-term low and unstable agricultural production in the region. Under such circumstances, it is undoubtedly the most important means to overcome the drought and get a better harvest by diligently taping water sources and developing small irrigation projects. Practice has proved that the drylands in the region after the water table, combined with soil fertilization, the output can be increased several times or even more than ten times; However, at present