| Jinfo Mountain in Chongqing is located in the transition zone of Sichuan basin and Yunnan-Guizhou plateau, and it is the typical Karst mountainous area of southwest China. The soil layer is thinner and the soil formation is slowly in the region. Its ecological environment is fragile and the contradiction between resources, environment and population is sharp. Unreasonable pattern of land use in the area has contributed to soil erosion and degradation of vegetation and the desertification phenomenon is serious It intensifies the contradiction between people and land resource and seriously affects the region’s sustainable development. The targets of this study were to analyse the temporal and spatial variation characteristics of land use and land cover changes(LUCC from year 2000 to 2010; to calculate and analyze the soil erosion characteristics of the study area with ARCGIS software and the RUSLE model, and to discuss relationship between the LUCC and soil erosion evolution for 10 years in the study area. The main conclusions are as follows:(1)The soil erosion degree is dominated by mild erosion and soil erosion showed improving trends in the study area. Average annual erosion modulus felt 0.65 t·hm-2·a-1 and the soil erosion amount went down from 2149.72 104t·a-1 in 2000 to 141.25 104t·a-1 in 2010. In soils with different strength levels of conversion, main conversions were mild and moderate erosion shifting to micro-erosion and soil erosion had been significantly improved. Regarding the soil erosion intensity change with different slope grade, soil erosion had aggravated within the scope with 0-10 degrees slope and the soil(2)erosion in some areas with10-15 degrees slope and the problem was still serious. The soil erosion phenomenon has been significantly improved where the slope is greater than 15 degrees.(3)The analysis of LUCC from 2000 to 2010 in the study area showed that the study area were dominated by woodland, dry land and paddy land during the study period and the sum of the three accounted for 90% of the total study area. The area of garden, woodland, grassland, construction land and bare land showed a growth trend, and the paddy field, dry land and water showed decreasing trends during the study period. Conversion between different land use and land cover was multiplex and the transformations between dry land, paddy field, woodland, grassland and road and construction land were quite frequent. The land use structure became reasonable under the different slope background. Area of dry land and paddy field reduced in areas with slope more than 15 degree, and they decreased much more in areas with slope more than 25 degree. The area of woodland, garden plot and grassland had been increased in areas.(4)There were close relationships between LUCC changes and soil erosion. The research results showed that the soil erosion intensity of dry land and grassland were the highest, and paddy field and forest land with low intensity. Relationships between changes of LUCC and soil erosion types showed that patterns, which protect soil from erosion, were shifts from dry land into woodland, woodland into road and construction land, dry land into road and construction land, grassland into dry land, grassland into woodland and paddy field into road and construction land, and shifts including from paddy field into dry land, woodland into dry land, paddy field into woodland and paddy field into grassland can exacerbate soil erosion. The study of erosion in areas, where is not suitable for farming in areas with 25 degree slope,showed that areas of cultivated land had been greatly reduced and woodland, grassland and garden land increased. The average erosion modulus decreased by 1.02t-hm·2-a-1 and the total soil erosion was reduced by 10.08*104t·a-1 and soil erosion was reduced because of leaving farmland for forest.(4)In order to rationally use of regional land resource and to realize the sustainable development, first, it was suggested to make adjustments of land use to the reasonable structure by changing farmland to forest land and grassland and closing hillsides to facilitate afforestation and to increase the ground coverage to reduce the loss of water and soil. Secondly, promoting economic forest and implementing no tillage or minimum tillage and other agricultural management measures were advocated to reduce the soil structure damage and disturbance in ecological fragile zone. In addition, we should strengthen the slope land rectification. And the less than 25 degrees areas can be cultivated through the land formation and improvement. At the same time, water and soil protecting measures should be strengthen surrounding the road and urban residential construction land areas. |
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