甘肃省西峰市土地利用变化的探讨

本文作者参加了1990年西峰市土地利用现状的调查工作。对西峰市1981年和1990年两次调查资料对比分析后发现:十年期间,耕地、草地分别减少了2733公顷(4万亩)和7333公顷(11万亩)。耕地、草地减少的总数,大约等于居民地、林地、园地和未利用地增加数量的总和。这些增加数分别为5067公顷(7.6万亩)、2867公顷(4.3万亩)、800公顷(1.2万亩)、1800公顷(2.7万亩)。作者研究了西峰市各主要土地类型的分布规律后指出:造成耕地、草地锐减的主要原因在于:(1)居民地侵占了塬面耕地;(2)新开垦的山坡耕地、园地又侵占了山坡草地,使草地成为主要的“受害者”。西峰市居民地与耕地面积之比,已从81年的12％,上升到90年的25％。若不改变这种不合理的使用土地资源的状况,数十年后,将会出现塬面“无地可耕”的危险局面。针对西峰市的实际,作者提出了对土地资源重要性的认识、加强对土地资源的管理、充分利用原有居民地等建议,并希望对土地资源质量方面的变化所引起的经济、生态方面的问题,做进一步的研究。

MONITORING THE DYNAMICS OF LAND RESOURCES OF XIFENG CITY WITH REMOTE SENSING METHODS

The land resources of Xifeng city, Qingyang Prefecture, were surveyed with remote sensing methods in 1990 and the results compared with those obtained in 1981. The results showed that the areas of cropland and grassland were reduced by 2733 and 7333 hectares, respectively, during the latest 10 years period. On the other hand the areas of residential land, woodland, orchards, and nonutilized land increased by 5067, 2867, 800, and 1800 hectares, respectively. This serious reduction in the area of crop fields on the table land of the Loess Plateau is mainly due to the increasing population pressure which needs more land for housing. The area of residential land increased to 25%of the total cropland in 1990 from only 12% in 1981. Subsequently, the grasslands on the slopes were turned into crop fields, and the area of grassland was reduced dramatically. This demonstrates clearly that there will be no land available for agriculture in several decades if the current situation continues. A strategy of how to manage land resources properly and rationally is suggested.