Effects Of Applying Green Waste Compost On Pb,Zn Contaminated Soil And Plant Growth

The soil in our country is seriously polluted by Pb and Zn,and the growth of vegetables is also affected.Applying amendments to repair heavy metal contaminated soil is a widely used chemical remediation method.In order to investigate the remediation effect of green waste compost on Pb,Zn contaminated soil,this paper used the leafy vegetable Brassica chinensis L.as an indicator plant,a greenhouse pot experiment was carried out to study the effects of different application rates of green waste compost(hereinafter referred to as compost)on the chemical properties,soil enzyme activity,the availability of Pb and Zn of contaminated soil and the plant growth of pakchoi and absorption of Pb,Zn by pakchoi.It is expected to provide simple,cost-effective and efficient remediation materials for Pb,Zn contaminated soil,and at the same time provide a direction for the effective use of green waste.The results were as follows:(1)The application of compost increased the contents of soluble salt,organic matter,total nitrogen,available nitrogen,available phosphorus and available potassium in Pb,Zn single and compound contaminated soil,and at the same time increased the activities of soil urease,catalase and dehydrogenase,the effect is best under 5% compost application.There was no significant effect of compost application on the p H of each contaminated soil.(2)The application of compost reduced the contents of available Pb,Zn in Pb,Zn single and compound contaminated soil.The contents of available Pb,Zn in each contaminated soil were the lowest under 5% application level.Compared with the control,the contents of available Pb in single Pb contaminated soil decreased by 17.83%;the contents of available Zn in single Zn contaminated soil decreased by 24.36%;and the contents of available Pb and Zn in compound contaminated soil decreased by 21.45% and 27.29%,respectively.The soil EC and nutrient content were the main factors affecting the contents of available Pb,Zn in the soil.(3)The application of compost reduced the Pb,Zn contents in the aboveground and underground parts of pakchoi on both single and compound contaminated soil.The contents of Pb,Zn in pakchoi were the lowest under 5% compost application rate,and significantly lower than the control.The application of compost improved the growth and physiological characteristics of pakchoi.The biomass,chlorophyll content,catalase activity and free proline content of pakchoi increased,while malondialdehyde content decreased.The effect of compost application on superoxide dismutase activity of pakchoi was not significant.The soil EC,nutrient content,enzyme activity and available Pb,Zn contents were the main factors affecting the growth and physiological characteristics of pakchoi.