Experimental Researches On Ecological Effects Of Peat And Plants' Ameliorating The Soil Media Of Coal Mining Wastelands

Most mineral resources in Jilin Province locate in the eastern Changbai Mountains. Of all the resources, coal,peat,diatomite, etc. distribute widely and are largely exploited. Mining activities and the waste they produced not only destroy and occupy lots of land resources but also bring about many serious environmental problems. Restoring the land productivity of mining areas and their health of ecological system is of great significance to the sustainable development of the eastern mountain areas in Jilin Province. The crucial part in ecological restoration of mining lands is soil media amelioration based on necessary land treatment and engineering measures. The coal mining wastelands in Wudaojiang township of Tonghua city, Jilin province are chose as the research objects. By adding peat as ameliorant and planting legume species alfalfa(Medicago sativa)and white clover(Trifolinw repens),the ecological effects of soil media amelioration in the coal mining lands are studied. All these are done to exploit the feasible pattern of media amelioration of mining lands. As shown in the study, the main obstacles in soil media amelioration of the coal mining wastelands are poor physical structure of the mined soil and extremely disproportional nutrient contents, especially the lack of N element. What's more, appreciably high pH value also restricts the growth of plants. Thus two aspects should be considered. First, the structure of mined soil should be ameliorated and the supply of nutrients be improved; second, the species should be planted which are capable of adapting themselves to the mining environment and have obvious ecological functions. Combining pot experimentation and chemical analysis, good ameliorative effects are gained by adding peat on appropriate proportion level and planting alfalfa and white clover. Contrasting with treatment A, the treatments B,C,D mined soil possess features as the following: moisture contents increase in turn; pH value falls down in turn with treatment D approaching neutral state; the contents of organic matter,total N,quick-acting N and quick-acting P increase continuously as response to the adding of peat with quick-acting N growing in the highest rate; effective Se,As get further decrease; the activity of urease and catalase also increase accordingly. Contrasting with treatment A, the alfalfa and white clover in treatment B,C,D grow better, especially treatment C and D, whose nutrients contents increase and contents of Se,As decrease continually. Both alfalfa and white clover have strong root system which can fasten mined soil as well as fix nitrogen. As a result the mined soil can develop better physical structure and stronger activities of microbes can be attained. According to the growth of the two species in 50 days, white clover has better growing trend and is less dependent on the adding of peat. Contrasting the differences in soil media amelioration of the two plants, white clover can advance the decrease of pH value more effectively; possess higher biologic absorption for heavy metal As; absorb more P,K with higher content of P,K in its body, thus can adapt to the living environment of mined media better. During the testing period, alfalfa and white clover act almost identically in N amelioration of the mined soil. In conclusion, according to the effects of amelioration,the growth state of plants and the consideration of economic aspect, adding peat with 10%～15% proportion and planting white clover and alfalfa can produce good amelioration effects.