Analysis Of Land Use Change And Suitability On Geomorphic Type Units In Shanxi Province

Land use/cover change is a reflection of a close interaction between human and nature, which has become the hotspot and frontier areas of global environmental change and regional sustainable development studies. The landform directly affects the state of land cover and land bearing capacity, obviously controls the redistribution of the light, heat and water resources, and determines the land use status and progress direction to a certain extent. Shanxi Province is located in the eastern of the Loess Plateau, the land of which is overused and suffered terrible erosion. Great changes have occurred in Shanxi Province under the implementation of the National Grain for Green Project and Afforestation Policy. So, the analysis of land use change and suitability on geomorphic types is of great significance to optimize the land use layout, make measures to reasonably prevent and control soil erosion and promote the ecological recovery.We analyzed the spatial and quantitative character of different topographic factors, geomorphic types and the law of land use change on geomorphic types by taking Shanxi Province as the study area, using the remote sensing and GIS technology. Then, we analyzed the soil erosion assessment of Shanxi Province to research the relationship between soil erosion intensity and land use type(including arable land, woodland and grassland). Finally, we explored the land use suitability based on the previous results. The main results and conclusions of this thesis are as follows:(1) The main types of land use were arable land, woodland and grassland, which accounted for over 95% of the area of Shanxi Province. The woodland and construction land presented a rising tendency, however, arable land and grassland were opposite. The percentages of arable land and construction land gradually reduced with the increase of the relief amplitude. Inversely, that of woodland increased as the relief amplitude increased. In terms of the change of area, the main changes of arable land, woodland and grassland take placed in medium relief mountains; Water area mainly changed in high relief mountains; Construction land mainly changed in plains and tablelands; and the change of unused land in small relief mountains was primary. In the view of dynamic degree, arable land, grassland and water area changed most seriously in high relief mountains. And the most serious changes of woodland, construction land and unused land respectively occurred in plains, hills and small relief mountains. The major transformations between land use types were different in geomorphic types. In the plains, the highest occurrence was that the grassland evolved into woodland. The major transformations in the tablelands were similar to that in the hills, that was the mutual transition between grassland and woodland. In the small relief mountains, the primary change was the mutual transition between grassland and woodland. However, the proportion of grassland into woodland was much higher than that of the woodland into grassland. While in the medium relief and high relief mountains, the main transition were that other land use types transformed into woodland. Thus it can be observed that the National Grain for Green Project and Afforestation Policy mainly occurred in the mountains, and the deforestation occurred in the gentle relief area.(2) The average annual amount of soil erosion in Shanxi Province from is about 3.58×108t, the average erosion modules is 2 287 t/(km2?a). About 47.7% of the total area was identified as present an erosion risk area. The area of arable land in the plains is largest, but the area and ratio of each erosion level higher than the slight erosion is lower than that in other geomorphic types. The woodland distribution in the plains and tablelands is less, which is mainly tolerable and slight soil erosion. And the distribution of woodland in the mountain areas is wide spreading with tolerable and slight soil erosion. The ratios of each level soil erosion of the arable land and woodland gradually reduce in each geomorphic unit, however, that in the grassland is different. Ratios of grassland in hills and mountains(mainly small relief mountains) increase until obtaining the maximum at medium soil erosion level, the decrease gradually.(3) The 5 indicators, including geomorphic types, slope, aspect, soil erosion and land use types, were selected as the land suitability evaluation factors. In accordance with the order of agriculture, forestry and stockbreeding, the study area was divided into five categories of land resources, including the land highly suitable for arable land, the land moderately suitable for arable land, the land suitable for woodland, the land moderately suitable for woodland, and the land suitable for grassland, accounting for 21.6%, 13.6%, 12.1%, 15.6% and 37.1%, respectively. In the plains and tablelands, it is suitable for arable land. In the hills and small relief mountains, it is suitable for woodland to promote ecological economy. And it is suitable for grassland in all mountain areas.