Effects Of Open-pit Coal Mining On Soil Physical And Chemical Properties Of Surrounding Grassland In Xilinhot

Xilinhot city of Inner Mongolia is an important coal production base of China.Coal industry not only brings economic benefits,but also has a great influence on local ecological environment.Soil is the base of terrestrial ecosystem,so the research on the soil physicochemical properties in mining area is the basis for a series of research works such as ecological restoration.This paper took a large open-pit mine in Xilinhot as research area.Through analyzing the soil physicochemical properties at different distances of surrounding natural grassland from mining interference area and comparing the soil physicochemical properties difference between natural grassland and artificial reclamation waste dump,this thesis explored the influence scope and influence degree of open-pit mining on the soil physicochemical properties of natural grassland and the soil improvement situation of waste dump after artificial reclamation.The main research results are as follows:(1)The vertical change of soil bulk density,water content,and p H value in the large open-pit mining area of Xilinhot City showed an increasing trend,and the vertical changes of soil total nitrogen,total carbon,available nitrogen,available phosphorus,and available potassium showed a decreasing trend.This indicates that the surface soil in this area has a large volume,high water content,and the soil is relatively alkaline with high nutrient content;the deep soil in this area has a small bulk density,low water content,and weakly alkaline soil with low nutrient content.(2)The soil bulk density and ammonium nitrogen content of the natural grassland around the mining area did not change significantly from the interference area.However,the soil p H showed a gradually decreasing trend with the interference distance.The water content,total nitrogen,total carbon,nitrate nitrogen,available phosphorus,and available potassium in the surface soil(0-10 cm)showed the distribution characteristics with 2 km as the threshold value,which was significantly higher the range of 2 km.While in the deep soil(10-30 cm),the grey correlation degree of soil physical and chemical indexes was the highest at the maximum distance of 3 km.This shows that mining activities in this area have a severe impact on grassland soil's physical and chemical properties within a range of 2 km.(3)The content of total nitrogen,total carbon,available nitrogen,available phosphorus,and available potassium in the south dump of Shengli Mine is lower than that of the natural grassland control area on the west side of Shengli Mine.The soil water content,bulk density,and p H value are higher than those in the natural grassland control area on the west side of Shengli Mine.This shows that the reclamation period of the South Dump of Shengli Mine is relatively short and the improvement effect is not significant,and further ecological restoration work is needed.