民勤绿洲地区土地资源结构及其合理利用

对干旱区内陆河流域下游具代表性的民勤绿洲地区土地资源结构进行了系统研究分析,得出了民勤绿洲各级各类土地资源的数量。就限制绿洲土地生产潜力的因素及强度进行了研究,其中水分限制占30.87%,土质限制占25.74%,盐碱限制占15.96%,肥力限制占8.96%。最后就土地资源结构与土地利用的合理匹配问题提出了两点建议:一是要加强农业部门结构和地域结构的优化调整;二是搞好水土资源结构平衡。

THE STRUCTURE OF LAND RESOURCES AND RATIONAL USE IN MINQIN OASIS

The paper has discussed the structure of land resources and its rational use problem from an example study on Minqin oasis situated in arid continental river's lower reaches region. The combined structure of land types in the studied area presented a diversified pattern from alluvial lacustrine plain, hill and low mountain to lake and basin depression. According to the ecological and economic properties of land in this region, the types of land suitability were divided into six classes:cultivable land, consisted of 1339%; cultivable, afforestable and also suitable for stock raising land, made up of 791%; cultivable and afforestable land, took 067%; afforestable land took 337%; land suitable for stock raising, took 1006%; land hard to use at present, took 6459%. The limiting factors of land productive potential were four types:① water factor, consisted of 3087%, in which the first grade took 386%, the second grade took 2039% and the third grade took 662%; ② soil texture, consisted of 2574%, in which the first grade took 488%, the second grade took 362% and the third grade took 1724%; ③ saline-alkali factor, consisted of 1596%, in which the first grade took 347%, the second grade took 255% and the third grade took 994%; ④ fertility factor, consisted of 896% and it belonged to the first grade totally. Moreover, according to the regional differences of land and water resources, two proposals about the structure of land resources and rational disposition of land use in this region were put forward. First, the optimization and adjustment of the structure of agricultural departments and regions should be strengthened. The quality of land resources in dam region is superior to that of lake area and with advantageous water irrigation condition, so it is a beneficial-type agricultural region with high output when high input. The secondary salinization was very serious in lake area which situated at the lower reaches region of Shiyang River basin. Nearly a half of croplands have been abandoned. Water-saving and salt-resistant economic crops should be planted in this region. On the premise of food self-sufficient, the type of crops should be changed to industrial crops type. Second, the equilibrium of land and water resources must be maintained. The cropland of inferior quality should be appropriately reduced. The water-supplying allocation must be rationally arranged by controlling the whole amount of water in the upper, middle and lower river-basin.