干旱区高强度开采地表裂缝对土壤微生物学特性和植物群落的影响

Effects of Surface Cracks Caused by High Intensity Coal Mining on Soil Microbial Characteristics and Plant Communities in Arid Regions

为了研究高强度开采地表裂缝对土壤微生物特性和植物群落的影响，以鄂尔多斯盆地腹地的神府-东胜矿区上湾煤矿开采沉陷区为研究对象，通过野外调查和试验分析裂缝两侧土壤和植物特征，结果表明：裂缝导致其两侧0-120cm范围内土壤水分和养分流失，距裂缝越近，土壤含水量和ω（碱解氮）越低，与距裂缝200cm处相比，裂缝上0～40cm范围内土壤含水量和ω（碱解氮）分别降低16．8％和29．9％；裂缝下0～40cm范围内土壤含水量和叫（碱解氮）分别降低27．8％和42．2％，地表裂缝显著减少了其两侧0～80cm范围内土壤中微生物数量，但超过80cm时则影响不显著，在地表裂缝两侧0～120cm范围内土壤脲酶和蔗糖酶活性被显著抑制，但当距离裂缝超过120cm时，裂缝则对两种土壤酶的活性没有显著影响，地表裂缝还会影响植物含水量，距裂缝越近植物含水量越低．与距裂缝200cm处的植物含水量相比，在裂缝上、下0～40cm范围内植物含水量分别降低8．4％、4．5％，地表裂缝通过干扰土壤理化性质和植物对水分的吸收，进而影响其生长，距裂缝两侧0-80cm范围内草本植物的生物量和盖度显著减少，但超过120cm时裂缝对植物生物量和盖度的影响不显著．

Coal greatly contributes to the energy supply in China. However, coal mining causes lots of ecological and environmental problems, such as soil surface cracks and vegetation degradation. Investigating the effects of coal mining on the characteristics of soils and plants can provide practical and theoretical values for vegetation restoration and ecological reconstruction in coal mining subsided areas. A field investigation and laboratory analysis experiment were conducted in the subsided area of the Shangwan coal mine in the Shenfu- Dongsheng mining area to explore the effects of surface cracks caused by high intensity coal mining on the characteristics of soils and plants. The results showed that the cracks resulting from coal-mining reduced soil moisture and nutrients from 0-120 em on both sides of the crack, and soil water and available nitrogen were lower nearer to the crack. Soil water and available nitrogen content in the 0-40 cm area on the upside of the crack were lower than those in 200 cm area from the crack by 16.8% and 29.9% , respectively. The differences on the downside of the crack were 27.8% and 42.2% , respectively. The soil microbial quantity in the 0-80 cm area on both sides of thecrack was lower than that beyond the 80 cm area, and the soil enzyme （e. g, urease and sucrose ） activity was significantly decreased in the 0-120 cm area on both sides of the crack, which indicated that the crack significantly decreased microbial quantity thereby inhibiting soil enzyme activities. Plant water uptake was also affected by the crack; it showed a trend of low plant water content near the crack, while it was not affected at distances further than 120 cm to the crack. Plant water contents in the 0-40 cm area on both sides of the crack were 8.4% and 4.5% lower than those in 200 cm area, respectively. The crack affected plant growth and decreased plant biomass and coverage by disturbing soil physicochemical property and water uptake of plant in the 0-80 cm area on both sides of the crack, while they were not significantly affected when the distance to the crack was more than 120 cm. According to the results, we concluded that the crack significantly disturbed the spatial soil physical, chemical and biological characteristics, thereby affecting plant community and water status. This study provided a theoretical basis for vegetation restoration and ecological reconstruction in coal-mining subsidence area.