Influence Of Coal Mining Subsidence On Physical And Chemical Properties Of Sandy Soil In Semi-arid Area

Coal mining subsidence resulted in a serial of environmental problems that prevent social economic development and affect sustainable development, thus research on the space variation law of land degradation in subsidence area, especially in semi-arid mining area, was an urgent issue for land reclamation. The sandy soil degradation mechanisms of Bulanta coal mining area in southeast Mu Us sandland have been analyzed and discussed from variation of basic physical and chemical properties and soil water content using spatial contrast method in this paper. The results showed:(1)Soil became more coarse and infertile in subsidence area. physical clay content decreased significantly(p<0.05); moisture constant (field water-holding capacity, wilting coefficient and available water capacity)decreased; organic matter, total N, total P and total K content within 20cm decreased, pH value changed little.(2)Soil porosity increased and bulk density decreased due to coal mining subsidence, however, variation of soil porosity and bulk density changed obviously in different dune location and profile layers(p=0.1); Fissure density and subsidence depth had little effect on soil porosity and bulk density.(3)Saturated conductivity increased after subsiding, infiltration depth increased and became deep with subsidence degree enhancement.(4)Subsidence aggravated soil water loss, caused water content of subsidence area to decrease significantly, especially from 0cm to 60cm, in bottom and depression of dune, and the lager fissure density was, the less soil water content was.