Comparative Study On Soil Remediation Methods Of Waste Rare Earth Minerals

The exploitation of rare earth ore has promoted the development of local economy,but also caused a series of environmental pollution problems.In this study,taking an abandoned rare earth mine in Huang She Village,Renju Town,Pingyuan County,Meizhou City,Guangdong Province as an example,We designed a soil remediation test with six plants with seven modifiers,and will explore the remediation effect of plant repair(including Glycine max(Linn.)Merr.?Stylosanthes guianensias SW.?Pennisetum giganteum z.x.lin?Pennisetum alopecuroides(L.)Spreng ? Pennisetum americanum x P.purpureum and Sorghum bicolor L.Moench)and Chemical repair(Organic fertilizer?biochar? passivation agent?bacteria agent and earthworm)on soil.We will measure the plant growth,soil fertility,and heavy metal contamination after 4 months and 8 months of repair.Comparing the changes of soil fertility and heavy metals with different plants and different soil improvers and their interaction,the optimal treatment mix was obtained.Research indicates:1)The soil of abandoned rare earth mine has lower fertility and higher content of cadmium,which exceeds the secondary standard of ?soil environmental quality standard?;2)With the repair and advancement,the soil fertility under all treatments was improved to some extent,and the contents of cadmium were reduced in different degrees,that is,all treatments had the effect of repairing the soil.3)Within 3 months of plant growth,Pennisetum alopecuroides(L.)Spreng and Pennisetum americanum x P.purpureum strong growing,Stylosanthes guianensias SW.weakly growing;4)After four months of plant growth,growing stong Stylosanthes guianensias SW,with the application of organic fertilizer or organic fertilizer + bacteria + earthworm,was the best repair effect.And the comprehensive fertility index of the soil under there treatments was higher than the soil under Pennisetum giganteum z.x.lin and Glycine max(Linn.)Merr.;5)After the first grass mowing,Pennisetum giganteum z.x.lin?Pennisetum americanum x P.purpureum and Stylosanthes guianensias SW.all grows strong.And Sorghum bicolor L.Moench was almost all infected with the disease and slowly growing.Pennisetum alopecuroides(L.)Spreng was no longer budding;6)After 8 months of plant growth,Pennisetum alopecuroides(L.)Spreng? Pennisetum americanum x P.purpureum and Pennisetum giganteum z.x.lin treated organic fertilizer+biochar+passivator,was better than the soil of other plants and modifier treatments;the soil under Pennisetum giganteum z.x.lin and Pennisetum americanum x P.purpureum with a variety of biochemical modified agent treatment was better than other the soil under other plants.