| Many abandoned mines in China have not only destroyed and occupied a large number of land,but also brought a series of serious environmental problems.Therefore,reclamation and ecological restoration are urgently needed.However,the ecological restoration of mines is faced with many difficulties,such as poor soil structure,lack of nutrients and heavy metal pollution.Sludge contains a large amount of organic matter and nutrients required by plants.The fine particles can improve soil structure and improve soil fertility and water holding capacity.If used properly,sludge has broad prospects for soil improvement and ecological restoration in abandoned mines.This project is the coupling of abandoned mine soil and sludge utilization in soil,sludge disposal and mining area to repair two problems,the original soil in Pingyuan County of Guangdong Province,Meizhou C ity,rare earth mining wasteland as the research object,the sludge compost used as modifier,and adding different amount of earthworm,through TCLP leaching experiment select the suitable amount of earthworm by different formula,and then will mine soil and sludge(primary 6:4 mixing ratio,earthworm amo unt respectively 0 kg-1,40 kg-1,60 kg-1,80 kg-1,respectively T1,T2,T3,T4,at the same time to mine soil as a control,denoted as CK),mining soil improvement,and carry out a variety of resistant plants(Eucalyptus,jatropha,acacia,sword bean pot experiment).By monitoring the improvement of soil physical and chemical properties,stability and effect of heavy metals and plant growth adaptability,screened the best prescription-soil phytoremediation technology,in order to achieve the ecological restoration of mining wasteland,city sludge disposal,heavy metal stable multiple goals,and ultimately achieve the purpose of using waste to treat waste,provide the feasible application direction the reclamation and utilization of sludge from the city fo r abandoned mines.The main results are as follows:(1)add only four kinds of sludge significant effects on plant biomass was added to four kinds of earthworms;in terms of plant biomass had significant promoting effect,the best effect for the T2 group;but between the three kinds of woody plants in T2,T3,T4 no significant difference;only in the sword bean,put the number of different the earthworm will constitute a significant difference.Overall,the biomass of the four plants was numerically ranked as follows: T2>T3>T4>T1>CK.(2)the application of sludge can significantly promote the absorption of nitrogen,phosphorus and potassium by plants,but after the addition of earthworms,the content of nutrient elements in plants decreases,but the accumula tion of nutrient elements is still higher than that of earthworms.(3)the contents of C u,Zn and Cd in plants were consistent.The content of elements increased with the addition of sludge,but no significant difference was found.The release of earthworms could increase the content of elements,but there was no significant difference between the three treatments.After applying the sludge,the content of Pb in plants decreased significantly.(4)Cu,Zn,Cd elements in the single factor pollution index is consistent,T1 group was significantly higher than that of T2,T3 and T4 group was significantly higher than that of CK group,three treatment but put a different number of earthworms,there was no significant difference.After adding sludge,the content o f Pb element decreased,and the single factor pollution index decreased.At the same time,the single factor pollution index of T2,T3 and T4 was higher than that of group T1.(5)the comprehensive pollution index,the pollution degree of CK group were safe,group T1 for heavy pollution;comprehensive pollution index of Eucalyptus,jatropha in the order of T1>T2>T3>T4>CK,shows that with the increase in the number of earthworms on soil pollution index,reduce soil pollution;and jatropha is for heavy pollution,may be related to the Cd element of single factor pollution index;... |
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