Vegetation Restoration Of Rare Earth Mining Abandoned Land And The Effects Of Soil Environment In South Jiangxi Province

In disturbed ecosystem,succession is carried out after vegetation is settled in.Therefore,vegetation recovery is very important to the resumption of mining wasteland.The study is based on the soil destruction caused by rare earth mining in Gannan.Then we carried out vegetation restoration to a rare earth mining wasteland in Anyuan County.Grasp the ecological process of vegetation restoration by regular observation of vegetation growth,understand plants adaptation to rare earth mine wasteland,and select the appropriate vegetation species of rare earth mine wasteland.Let soil seed bank play a role through soil replacement,screening native species for rare abandoned mine;by planting hybrid species and a single species in two modes,studied the configuration of the plant.By measuring soil characteristics to understand the different improvement of soil pHysical and chemical properties between two modes;understand soil improvement on restore areas on the time scales.The main results are as follows:(1)The original dip mining method and heap leach mining methods both have an impact on soil physical and chemical properties,change soil structure,lead to nutrient loss.Heap leaching way make soil TN,TC,TP,and water content decline significantly;The original way make soil TC and TP,water content decreased significantly.In addition,both mining methods have an impact in different slope posistion on soil TP,PH.(2)The area of vegetation recovery after one and a half years,plants grow well,species increase,dominant species grow gradually obvious,companion species are distributed evenly.Plant overall coverage and diversity index improved very well:plant overall coverage reached 90%,A-E model coverage are above 78%;Shannon-wienner diversity index of vegetation restoration reached the normal level(1.5 3.5),Simpson diversity index of vegetation restoration reduced,Pielou diversity index of vegetation restoration tends to be stable.Coverage,the number of species and vegetation diversity of each mode have been significantly improved.In addition,slash pine,Miscanthus,Nigatake can be adapt to the harsh living environment of rare earth mine better.Native species:rhus,the white-backed leaves,millet bran,gotu kola and other can grow well too.(3)Soil physical and chemical properties of each mode has been significantly improved in the region of vegetation restoration,bulk density,the proportion of gravel,ammonium nitrogen and nitrate nitrogen of each mode are lower than bare land;water content,TN,TC,TP and effective P,TK,available K of each mode are higher than bare land.In general,the soil physical properties have been improved significantly,according to the classification standard of soil fertility quality evaluation parameters,the soil physical properties are in the primary to secondary standards;but chemical properties are still on the low side,in four to five standards.So vegetation restoration need to takes a long time to restore soil nutrients.(4)The best model of vegetation restoration is wetland pine + Nigatake + Miscanthus.In addition,mixed cropping patterns is better than single planting trees model to the entire ecosystem restoration:the species richness and Shannon-wienner diversity index and Pielou evenness index were significantly higher than single mode,Simpson diversity index was significantly lower than that of single mode;Its surface water content,deep PH was significantly higher than that of single model,surface gravel proportion,deep gravel proportion were significantly lower than that of single mode;the ammonium nitrogen and nitrate nitrogen content are significantly lower than that of single mode,TP?TK?effective P?available K content are significantly higher than the single mode.