Effect Of Coal Dust On The Growth Of Plants In Grassland Near Coal Mining In Arid Region

Opencast mining (open-pit) would have an affect on the ecology and environment surrounding the coal mining. Fugitive dust (coal dust and waste rock dust) produced from the open-pit process are important pollutants, which is particularly important in coal mining of arid and windy Xilin Gol Grassland, Dust pollution in the coal mining was not only bring disaster to the large area of grassland surrounding coal mining, but also seriously affected the health of residents and livestocks. In this study, West II coal mining of Shengli Coal fieldin Xilinhot was selected as experiment site. The steppe surrounding the coal ming was serveied, in June2012-December2013. Vegetation height, coverage and density were determined in field tests. An indoor simulation test was conducted to measure the roots and leaves parameters under different dust conditions. In order to study the effect of dust on the growth of five plant. The results were showed as follow.(1) Through the monitoring of dust emissions, the result show that the dust deposition rate was0.36g·m-2in the upwind of prevailing wind (in northwest side of mine), which was0.59g·m-2in the downwind site (in the southeast part of mine). The rate was0.26g·m-2and0.36g·m-2at the upwind (in the southwest part of mine) and downwind site (in the northeast part of mine) in the vertical direction of prevailing wind, respectively. The most polluted site was in the southeast part of coal mining. The content of heavy metal (cadmium, chromium and lead) in the dust was higher than that in background values of soil near the coal mining.(2) In the enclosed area, the important value of perennial herb was reduced by the dust pollution. The Margarlef richness and Shannon-Wiener diversity index of the moderately polluted grassland were increased(3) In the grazing areas, the importance value of perennial herb was greatest in the mildly contaminated grassland. Compared with the enclosed area of background site, Margarlef richness and Shannon-Wiener diversity index were increased by the dust pollution.(4)The root length, root surface area and root volume of plant were obviously inhibited by the dust pollution. The root length and root forks of Agropyron cristatum were mostly inhibited. The surface area of Agropyron cristatum and Melissilus ruthenicus were also mostly inhibited.(5) The dust pollution had a negative effect on the plant photosynthesis and transpiration of leaves. The net photo synthetic rate and transpiration rate of Agropyron cristatum were obviously inhibited. The intercellular CO2concentration of Chenopodium acuminatum and the stomatal conductance of Melissilus ruthenicus were obviously reduced.