基于GIS的黄土高原土地坡度构成及垦殖率地域分异研究

Land Gradient and Reclamation Ratio on Loess Plateau Based on GIS

土地坡度构成和土地开垦情况是影响土壤侵蚀强度的重要方面。利用 GIS方法对黄土高原土地资源进行分析 ,探讨了利用地理信息系统技术来确定黄土高原县域不同坡度级的土地面积比例、耕地面积比例和垦殖率及其空间分布。研究表明 :黄土高原地区土地和耕地≥ 15°和≥ 2 5°比例较大的县主要集中在黄河中游几条支流流域和六盘山及以西地区。在这些地区 ,≥ 15°陡坡地的垦殖率在 0 .1以上 ,有些地区达 0 .5 ,是黄土高原陡坡耕地主要集中区 ,也是侵蚀严重的地区。

The soil erosion on Loess Plateau is one of the most serious problems, which re sulted in series of severe environment question in the Yellow River valley. Land gradient and reclamation ratio are important factors to soil erosion. On the base of GIS method, land resources on Loess Plateau was analyzed , and with the degree of ground gradient varying, the land proportion, the plant ation proportion, the reclamation ratio, and their zone distribution were ascert ained. The results showed, the counties that the proportion of land and plantat ion gradient exceeding 15° and 25° is bigger mainly distribute in the several branches valley in the middle reach of Yellow River and Liupan mountain and its west, in which reclamation ratio of land gradient ≥15° exceed 0.1, some extend ing 0.5. The several branches valley in the middle reach of Yellow River and Liu pan mountain area are not only the mainly concentrated section for steep sloping plantation on Loess Plateau, but also the area of high erosion.