宁夏耕地压力与社会经济发展耦合时空特征分析

Spatial-temporal characteristics of coupling pressure index of cropland with social economy in Ningxia Hui Autonomous Region

根据耕地压力指数和重心坐标模型,计算了宁夏回族自治区1980-2012年耕地压力指数及GDP重心坐标,在此基础上分析了耕地压力指数在时间上的动态变化及空间上的差异;并通过地理关联率的计算,进一步探讨了耕地压力指数与GDP在空间上的耦合关系。结果表明:30多年耕地面积减少了37.8×104 hm2,最小人均耕地面积和实际人均耕地面积不断减小,耕地压力指数总体随时间呈减小趋势,到2012年减小到0.72;但各县(区)耕地压力差异较大,北部能源开发区一直是宁夏耕地压力最大的地区;中部干旱区和南部黄土丘陵沟壑区在2000年以前耕地压力较大,而后明显减轻。经济发展、农业科技、水利工程及生态移民政策共同影响了耕地压力变化。到2012年耕地压力和GDP地理关联率为0.85,表明两者之间的地理联系率较高。

Pressure index on cropland reflects the land carrying capacity. According to the model of the pressure in- dex of cultivated land and the centre of gravity, the paper calculates the pressure indexes of cultivated land and the GDP barycentric coordinates in Ningxia Hui Autonomous Region from 1980 to 2012. And then the dynamic changes of the indexes and that of spatial differences were analyzed using GIS. At last, the coupling relationship between the pressure indexes of cultivated land and GDP were analyzed by calculating the geographical relevance. The results show as follows ： （ 1 ） the area of cultivated land decreased by 37.8 x 104 hm2 in the past 30 years, and the minimum per capita arable land area and the actual per capita arable land were decreasing, the pressure index of cultivatedland decreases with the overall time, the values of index decreased from 1.08 in 1980 to 0.72 in 2012. These indicate that the cultivated land productivity greatly improved and the grain yield per hectare significantly increased. （2） the pressure indexes of cultivated land for different counties are quite different. The Northern Energy Development Zone has been the most stressful area of cultivated land in Ningxia, such as, Dawukou District of Shizuishan City, the values of index was up to 2.32 in 1980. Loess Hilly and Gully Region in southern and arid area in middle of Ningxia had the larger pressure of cultivated land before 2000, and then the pressures of cultivated obviously reduced. On the contr- ary, along the Yellow River counties have lower pressure in cropland. The forces are from the following some policies and measures, such as agricultural science and technology, water conservancy project and ecological immigrant. （3） the geographical relevance indicates that the change of the pressure of cultivated land and the GDP development are closely linked, and the spatial distribution was consistent. Also, the same trend for the centre of gravity of the pres- sure index of cultivated land and the GDP dynamically moved in spatial. From the analysis above, we thought that the change of pressure of cultivated land was influenced by the social economic development, agricultural science and technology, water conservancy project and ecological immigrant. In the future, Ningxia Hui Autonomous Region should develop ecological agriculture, strengthen the construction of basic agricultural facilities, especially construct irrigation and water conservancy and transform medium-low yield farmland, enhance the ability to resist drought of cultivated land, in order to improve land use level and reduce the pressure of cultivated land in Loess Hilly and Gul- ly Region in the southern area and arid area in the middle of Ningxia.