Study On Screening And Improvement Effect Of Manganese Slag Improver Amended

Manganese ore slag has high content of heavy metals,strong toxicity and poor physical and chemical properties of the soil,which makes phytoremediation difficult.At present,most of the plants used for phytoremediation of manganese slag are herbaceous plants.In this study,the woody plant Paulownia fortunei and Nerium indicum were used as plant materials for manganese ore slag restoration,using different concentrations of organic matter(peat soil,mushroom residue)and inorganic matter(meteorite,attapulgite).The slag single improver was used to explore its effect on the repair of Paulownia fortunei and Nerium indicum in the manganese ore district,so as to screen out a single improver with good improvement effect,and selected the mushroom residue and the attapulgite as the composite modifier according to the results of the first year test,the composite modifier ratio screening and improvement effect research.The main results of the study are as follows:1 Comparative Study on Screening and Effect of Manganese Slag Single Modifier(1)The four kinds of modifiers such as peat soil,mushroom residue,vermiculite and attapulgite can effectively increase the organic matter content of slag,and the organic matter content in the slag increases with the increase of the concentration of the organic modifier,and the concentration increases with the application of the inorganic modifier.(2)Peat soil,mushroom residue,vermiculite and attapulgite can promote plant growth.The promotion effect of mushroom residue is the most significant,and there are differences among plant species.The biomass increase and root morphology index of Paulownia fortunei Both are higher than Nerium indicum.(3)The modifier can significantly reduce the acid extractable state of different heavy metals in the slag.Peat soil,attapulgite and vermiculite can significantly reduce the acid extractable state of Zn,Cu and Pb in the slag,respectively.The attapulgite significantly reduces the acid extractable state of Mn in the soil.(4)The cumulative amount of four heavy metals in Mn,Zn,Cu and Pb increased with the increase of the concentration of the modifier,and the total enrichment of Paulownia fortunei to heavy metals was higher than that of Nerium indicum,and the biomass increased.The law of change is consistent.Among them,the ability of plants to enrich manganese was stronger under mushroom treatment.The manganese accumulation of oleander and Paulownia fortunei under the treatment of 30%mushroom residue reached 11.65 and 20.77 mg,respectively,which was 7.8 times and 11.61 times that of the unmodified group.2 Comparative Study on Screening and Effect Comparison of Addition Amount of Manganese Slag Composite Improver(1)The mushroom slag and the attapulgite rod are ratioed by 1:1,1:2 and 2:1 respectively.The three ratio compound modifiers can reduce the slag pH value.The mushroom slag:the attapulgite is 2:1,the slag has the lowest pH value.Three composite modifiers can increase the slag organic matter content,reduce the bulk density,increase the porosity and the content of catalase and alkaline phosphatase in the slag,and the improvement degree showed a trend of 1:1<1:2<2:1 in the three composite ratios.(2)The contents of Mn,Pb,Zn and Cu in Nerium indicum and Paulownia fortunei matrix decreased after the action of three kinds of composite modifiers,and the content of Mn in slag decreased with the increase of the ratio of mushroom slag.When mushroom residue:attapulgite was 2:1,The effect of the composite modifier treatment is most significant.The acid extractable state of Mn,Pb and Zn in the slag increased after the application of the modifier,and the acid extractable state accounted for the highest proportion in the mushroom residue:attapulgite ratio of 2:1,while the Cu acid extractable state and organic.The total proportion of the combined state decreases,and the conversion to the Fe-Mn oxide bound state and the residual state.(3)After applying the compound modifier,the plant height,root morphology and biomass of Nerium indicum and Paulownia fortunei increased,indicating that the mushroom residue-attapulgite composite modifier can promote plant growth.When the application ratio of mushroom slag and attapulgite was 2:1,the plant height of Nerium indicum and Paulownia fortunei was the highest,1.5 times and 2.4 times higher than that of CK.The root morphology and biomass of Nerium indicum and Paulowniafortunei showed a trend of CK<1:1<1:2<2:1,and the root mor:phology and biomass of Paulownia fortunei were more obvious than Nerium indicum.(3)After applying the composite modifier,the contents of heavy metals such as Mn,Pb and Zn in Nerium indicum and Paulownia fortunei increased,and the content of heavy metals in stems and leaves decreased,and in the case of mushroom residue:attapulgite was 2:1.The increase in heavy metal content in plant roots is most pronounced.The cumulative amount of four heavy metals in Mn,Pb,Zn and Cu increased significantly after applying the composite modifier,and the overall trend showed CK<1:1<1:2<2:1,and the accumulation of heavy metals in Paulownia fortunei higher than the accumulation of heavy metals in Nerium indicum.