矿区开采沉陷农用土地质量空间变化研究

提出利用土地环境条件、土壤物理特性、土壤养分因子反映矿区土地质量．通过徐州矿区的试验研究，分析了开采沉陷引起的土地环境条件、土壤物理特性、养分因子的变化规律，得出：开采沉陷后土地产生附加坡度，排灌标准明显下降，农田林网防护范围缩小，地下水位埋深相对变浅；土壤物理特性中下坡位置土壤含水率明显升高，土壤容重几乎没有变化，总孔隙度在下坡处明显变小；而土壤养分因子上坡各项指标普遍低于对照田，下坡位置要高于对照田，上、下坡的养分因子平均值与开采沉陷前没有显差异，利用熵流指数模型分析知：开采沉陷后排灌条件差、防护林防护范围小、地下水位埋深不理想是导致开采沉陷区土地生产力下降的主要原因。

Change of Agricultural Land Quality due to Mining Subsidence

It is proposed that mined land quality can be estimated by environmental conditions, soil conditions, such as nutrient contents, physical factors. The laws of the change of environmental conditions and soil conditions in subsided area were proposed by means of field survey. The results show that 1) additional slope is formed, the level of drainage and irrigation decreases strikingly, the defense area by net of farmland forestry reduces, and the level of phreatic water becomes shallow after subsided; 2) soil water content in low slope increases, bulk density nearly keeps constant, and total porosity diminishes at down slope; 3) all indices of soil nutrient in the contrast farmland are lower than those in down slope and higher than those in up slope, but the average of soil nutrient indices in down slope and up slope is nearly equal to contrast farmland. The poor conditions of drainage and irrigation, the small portion of defense area by net of farmland forestry, and the shallow level of phreatic water in subsided area are the primary factors to cause land productivity reduction by means of entropy exchange model.