Study On Dynamic Change Of Land Cover In The South Margin Of Maowusu Sandy Lands

Land resources are the most important and essential nature resources to human. So analyzing the land use information, forecasting the land use changes are the premise of managing land use correctly.Dynamic monitoring about two periods of vegetation cover and land use / land cover situation of the year 1986 and the year 2000 are performed separately in this thesis. Vegetation cover and land-use thematic maps are made automatically with the help of GIS software packages. Based on a comparative analysis, it is safety to draw a conclusion about the trend for land cover changes of Jingbian County and also the mutual conversion ratio and type does. Main conclusions are as follows:(1)Vegetation cover of the study area is mainly belonging to the middle- and lower- vegetation cover type. In 1986, this kind of middle- and lower-vegetable cover area is 443445.19 hm2 of 89% the total area; while in 2000 it is 395962.89 hm2 of 85% the total area, but higher-vegetation coverage increased, it covers 54,807 hm2 more than that of 1986.(2) According to the statistics of absolute land use change area, area of woodland, grassland and unused land changes largely. Unused land area reduces 125668.15 hm2 these years, woodland and grassland area increased 108018.12 hm2 and 93626.91 hm2. Farmland and land for the construction changes a little. Farmland area decreases 55249.33 hm2, and land area for the construction increases 18391.53 hm2. Water area and sand area change in the least, 2452.96 hm2 area reduced at water area while sand area increased 116.95 hm2. According to the area changes of these different land use type from 1986 to 2000, the serials is unused land > woodland > grassland > waters area > land for construction > farmland > sand. According to the rate of change of land use types itself, the order is grassland > water area > forest land > land for the construction > unused land > farmland > sand.(3) Higher forestland and grassland vegetation coverage increase the impact of wind-erosion. In the northern Jingbian county sandstorms days reduced and the number of high winds days. Sandstorms weakened under the expansion of the sand control.(4) Driven forces have more impact on land use type conversion. According to the analysis of this thesis, natural factors varies little in a short period of time, human driving factors is at the leading position. Changes of population, economic development situation, urbanization, policy guidance and technical progress can lessen area of farmland, unused land and waters area, increasen construction land, woodland and grassland.