黄土区大型露天煤矿煤矸石自燃对复垦土壤质量的影响

为了研究煤矸石自燃对复垦土壤质量的影响，以复垦13 a的平朔安太堡露天矿区南排土场1420平台正常复垦土壤与自燃退化土壤为研究对象，分析研究了煤矸石自燃对复垦土壤的理化性质、重金属含量、土壤微生物区系和土壤酶活性的影响，并选取原地貌土壤为参照。研究结果表明， 煤矸石自燃对复垦土壤的物理性状影响很大。土壤体积质量、总孔隙度、毛管孔隙度与非毛管孔隙度、田间持水率发生突变。南排1420煤矸石自燃复垦土壤的体积质量显著比正常平台和原地貌土壤的要小，总孔隙度要大，而且主要是非毛管孔隙度，表层土壤和20～40 cm的土壤的非毛管孔隙度高达42.08%和39.49%，远高于正常平台和原地貌土壤，而毛管孔隙度仅有16.41%和15.60%，远低于正常平台和原地貌土壤，田间持水率仅为14.92%和13.11%，为正常平台复垦土壤的47.76%和39.95%。煤矸石自燃可以降低复垦土壤的有机质、速效磷质量分数以及pH值，而提高复垦土壤表层速效钾的质量分数。煤矸石自燃可增加复垦土壤0～20 cm中Pb、Cr、Hg的质量分数，特别是Cr和Hg的质量分数略高出土壤环境质量一级标准。煤矸石自燃对土壤微生物数量影响甚大，煤矸石自燃复垦土壤微生物数量极少，仅为正常平台复垦土壤的0.82%，其中细菌为正常平台复垦土壤的0.80%，放线菌为1.64%，真菌为1.24%。煤矸石自燃可大大降低复垦土壤的过氧化氢酶和蔗糖水解酶活性，特别是蔗糖水解酶活性，而表层复垦土壤的脲酶活性略有提高。总之，煤矸石自燃造成复垦土壤极度退化，大大降低了复垦土壤的质量。

Effect of gangue spontaneous combustion on reclaimed soil quality of large-scaled opencast mine in loess area

For researching the effect of gangue spontaneous combustion on reclaimed soil quality, soil physical and chemical properties, contents of heavy metals, soil microbe and enzyme activities were studied by taking soils having been reclaimed for 13 years as objects, which located in south refuse dump of Antaibao large-scaled opencast mine in Pingshuo County, Shanxi Province, and original geomorphologic soil was chosen as the references. The results showed that the physical properties of reclaimed soil were influenced by gangue spontaneous combustion significantly. Compared with normal platform and original geomorphologic soils, bulk density of gangue spontaneous reclaimed soil was lower and total porosity was higher. Non-capillary porosity in 0-20 cm and 20-40 cm layers of gangue spontaneous combustion reclaimed soil were up to 42.08% and 39.49%, respectively, which were much higher than that of normal platform and original geomorphologic soils. However, capillary porosity in 0-20 cm and 20-40 cm layers of gangue spontaneous combustion reclaimed soil were 16.41% and 15.60%, respectively. Field water-holding capacity in 0-20 cm and 20-40 cm layers of gangue spontaneous combustion reclaimed soil were only 14.92% and 13.11%, which were 47.76% and 39.95% of that of normal platform, respectively. Contents of organic matter, rapidly available phosphorus and soil pH value were decreased and content of readily available potassium was increased due to gangue spontaneous combustion. The mass fractions of Hg, Pb and Cr, especially Hg and Cr were increased significantly. Total microorganism in gangue spontaneous reclaimed soil was 0.82% less than that of normal platform reclaimed soil. The amount of bacteria, actinomycetes and fungi were 0.80%, 1.64%, 1.24% of that of normal platform reclaimed soil, respectively. The activities of catalase and invertase were decreased and urease was increased slightly in gangue spontaneous combustion reclaimed soil as compared to normal platform reclaimed soil. In a word, gangue spontaneous combustion caused reclaimed soil extreme deterioration and decreased reclaimed soil quality.