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To study the formation process of feldspathic sandstone and sand compound soil in the Mu Us Desert, 1:1, 1:2 and 1:5 ratios of feldspathic sandstone and sand were mixed to obtain compound soil to plant crops, and aalyze the rules of changes in water-stable aggegates of the compound soil among the 4 years crops gowing process. The results showed, before crop planting, the order of mass percent of>0. 25 mm and 0. 25-2. 00 mm water-stable agregates in three kinds of compound soil was 1:1 >1:2 > 1:5, showing that the overall content was low; the mass percent of > 0. 25 mm water-stable agregates remained at 18. 38%-28.22%; the mass percent of 0. 25-0.50 mm, 0.50-2.0 0 mm, 2.00-5.0 0 mm, and > 5.00 mm water-stable agregates was close with each other in each kind of compound soil. After 4 years of planting, the mass percent of > 0.25 mm water-stable aggegates in 1:2 compound soil increased significantly and exceeded other 2 kinds of compound soil, reached 32. 34%; the main components of > 0. 25 mm water stable aggegates in 1:1, 1:2, and 1:5 compound soil were 0.25-0.50 mm (53. 54"%), 0.25-0.50 mm (59.43"%), 0.05-2.00 mm (52. 16"%), aggregates; 0.25-2.00 mm aggegates increased significatly in H three kinds of compound soil, with the highest increase in 1:2 compound soil; the orgaic matters of 1:2 compound soil were significatly correlated with 0.25-0.50 mm and 0.25-2.00 mm water-stable aggregates. The results showed that the ratio of 0.25-2.00 mm aggregates in the three kinds of compound soil was increased after 4 years of crop planting and 1:2 compound soil was most favorable for the formation of aggegates. [ABSTRACT FROM AUTHOR]

In order to ease the contradiction between people and land and ensure the needs of construction land and farmland, this paper analyzes the demad and regional land development background, and points out the problems of the development of the land in China: late start of land development and utilization practices; declining back-up resources and shaply increasing costs; new resources and environmental problems brought about by development and utilization of land in some areas. This paper presents a new opportunity and strategy for land use transition : giving full play to the aricultural and geographical advantages of farming-pastoral area; carrying out water-saving technologies and intensive use of agricultural land in water-deficient areas, in order to achieve reasonable and efficient development and utilization. [ABSTRACT FROM AUTHOR]