Impact Of Mining Ground Fissures On Soil Quality And Damage Assess In Yushen Mining Area

Coal,as a main energy in China,is more than 70%in the domestic energy consumption.In a short run,it's hard to change.Because of coal mining,the surface environment of the mining area has been damaged.The ecological environment of the mining area has become a major constraint to the sustainable development of the mining area and the region.One o.f problems induced by mining is ground fissures.And it can cause serious damages to the surface soil.It is necessary to evaluate the quality of the soil in the fracture area,which could be basic for soil remediation and ecological reconstruction.This study was carried out in Yushen mining area.Cracks with widths of 0?20cm(small),20?40cm(medium)and 40?60cm(large)were studied,and set virgin zone as contrast.The change rule of soil physical and chemical indicators was investigated,and the soil fertility in the mining area was evaluated.The main research results,are as follows:(1)With the increase of the width of crack,the soil moisture content of the surface layer of 20?40cm from the crack is reduced by 9%to 11%.,and the moisture content of the topsoil from the crack 60cm increases by 20.9%.At 40?60cm from the crack,the soil porosity increases with the width of crack.It's about 24.65%.With the increase of the width of crack,the clay and fine particles in the topsoil are lost by nearly 30%,and the soil desertification is obvious.At 0?20cm from the crack,organic matter content is positively correlated with crack with and distance from the crack.And the maximum is 4.18g/kg.In the medium cracked area,the total nitrogen,available phosphorus and ammonium nitrogen content is the largest.It indicates that the soil nutrient index is less affected by the mining ground fissure in the medium cracked area.(2)In the same width cracked area,the soil moisture content increases with depth,and the range is 10%?19%.when the sampling depth is 0?80cm,the rate of water content in the fracture zone is 10%?20%larger than in the control area.The vertical characteristic of soil particle size in cracked area is that the clay,fine powder content is low,and the fine sand content is high in topsoil.And compared with the control area,the clay content decreased by nearly 50%;the sand content increased by nearly 100%;and the soil desertification trend was obvious.The soil organic matter content decreases with depth.And the range is from 43.69%to 68.18%.The soil organic matter content of topsoil at 60cm from the crack is about 22.25%higher than 20cm away from the crack.The content of total nitrogen in the soil decreased with depth.And the total nitrogen content of the soil in the 0?10cm layer was about twice that of the 40?60cm layer.The content of ammonium nitrogen in small cracked area increased with depth and then decreased.And at the same depth,the content of ammonium nitrogen increases with the distance from crack,and the maximum is 21%.The available phosphorus and potassium remained basically unchanged,(3)The Nemerow comprehensive index method was used to evaluate the soil fertility in the mining area.The soil fertility comprehensive coefficients of the fracture area and the control area were less than 0.9,which was a poor soil.After comparison,it is found that the soil fertility comprehensive coefficient in the fracture zone is ranked as follows:small crack>medium crack>large crack.Based on the analysis of the fertility coefficient of each index,the available potassium fertility coef,ficient ranges from 2.17 to 2.45,which is a fertile level.Soil organic matter,total nitrogen,and available phosphorus fertility coefficients are all less than 0.9,which is a barren level.It can conclude that the content of organic matter,nitrogen and phosphorus in the fracture zone is insufficient,compared with virgin zone.