Study On Soil Physicochemical Properties Of Different Vegetation Restoration In Abandoned Rare Earth Mining Area Of South Jiangxi Province

The rare earth mine exploitation of the South Jiangxi area has brought serious destruction of ecological environment.Therefore,the management for rare earth tailings seems especially important.Vegetaion restoration has been gradually spread in south of Jiangxi provience as an important means to control the pollution.Thus it is urged and necessary to explore a useful mode of vegetation restoration in the place of discarded rare earth tailings.Our study is based on the vegetation restoration plots built by Nanchang University in abandoned rare earth tailings,which located in Anyuan county.It sets the vegetation restoration of abandoned mining area of rare earth tailings in Jiangxi Anyuan county as the research object,selects four good vegetation restoration modes(W: the mode of wetland pine with tree,shrub and grass,S: the mode of schima superba with tree and grass,E: the mode of eucalyptus with tree and grass,P: the mode of paspalum notatum with grass and shrub)has been carried on the basic physicochemical properties of soil,soil nitrate nitrogen and ammonium nitrogen content and soil microbial diversitites and related indicators monitoring,then analyze the improvement of the physicochemical properties of soil under different vegetations restoration mode,finnally provide theoretical basis for the selection of suitable vegetation recovery mode for Jiangxi rare earth abandoned mines.The main results are as follows :(1)The basic physicochemical properties of soil has improved dramatically.After vegetation restoration,various models of soil bulk density were lower than bare land.While pH,total C,total N and total P of soil were significantly higher than that of bare land.Within the overall improvement,W is the best with the soil pH,total C,total N and total P increased by 10%,21%,13% and 21% respectively.(2)The vegetation restoration changed the existence forms of the soil effective nitrogen obviously.The extensive use of ammonium sulfate in the process of mining tailings has caused the effective nitrogen seriously overproof.After vegetation restoration,various models of soil ammonium nitrogen and nitrate nitrogen content were lower than that of bare land.From this,W is the optimal to improve the effect of nitrogen in soil,with the ammonium nitrogen and nitrate content was reduced by 181% and 527%.(3)The vegetation restoration enriched the diversity of microbial in the soil.After vegetation restoration,microbial abundance of all kinds of patterns was higher than that of bare land obviously.Comparing different vegetation recovery modes,the abundance of microbial in W patterns of is the highest,and the number bacteria,fungi and actinomycetes colonies respectively increased by 149 times,82 times and 230 times.Overall,the vegetation restoration process can improve the structure of the soil,increase the soil nutrient content,change the forms of effective nitrogen in soil,enrich the diversity of microbial,thus improve the physicochemical properties of soil.Among these different restoration modes,the best model of vegetation restoration is W.It is suitable for the promotion of vegetation restoration in Jiangxi rare earth abandoned mines.