Method for extracting zinc from farmland soil continuously by utilizing hyper-accumulation plants

Abstract

The invention discloses a method for extracting zinc from farmland soil continuously by utilizing hyper-accumulator plants, which comprises the following steps of: applying 50 to 800 milligrams of soluble phosphate fertilizer to each kilogram of zinc-polluted soil, and applying 0.2 gram of nitrogen and 0.2 gram of potassium which serve as base fertilizers; pre-culturing stems with axillary buds of sedum alfredii hance by using nutrient solution for 3 to 4 weeks, transplanting seedlings of the sedum alfredii hance of which the root system is eugenic and the plant height is between 6 and 8 centimeters in the treated zinc-polluted soil, managing growth according to the conventional farming method, harvesting overground parts of the sedum alfredii hance every four months, and reserving 2 to 3centimeters of the stems of the overground parts during harvesting; and harvesting the overground parts of the sedum alfredii hance at regular intervals to reduce the concentration of the zinc in thesoil continuously. The method is easy and convenient to operate, the physicochemical property of the soil can be improved effectively, and the repair efficiency of the zinc-polluted soil can be improved; and the method has the advantages of small investment, small work amount, simple management technical requirement, wide application range and the like, and soil environment is not damaged.

Description

technical field [0001] The invention relates to a phytoremediation method for compound polluted farmland soil by heavy metals, in particular to a method for continuously extracting zinc from farmland soil by using hyperaccumulative plants, and belongs to the technical field of environmental treatment of polluted soil. Background technique [0002] Soil heavy metal pollution is an important factor affecting the sustainable development of agriculture and the quality of ecological environment in my country. Due to the large amount of agricultural pesticides and fertilizers invested in my country, and most of them are distributed in the suburbs, they are greatly affected by urban industrialization pollution, so soil heavy metal pollution is the most serious. It is estimated that the area of ​​heavy metal pollution in its farmland is 300 million mu, and the economic loss caused by heavy metal pollution is nearly 20 billion yuan every year. The current heavy metal pollution in fa...

AI Technical Summary

Problems solved by technology

However, there are many problems in it: (1) chemical chelating agents generally have strong phytotoxicity, and higher concentrations will seriously inhibit plant growth, reduce biomass, and affect repair efficiency; (2) after chelating agents activate heavy metals, their heavy metals will Compounds and chelating agents are not easy to degrade, and there is potential secondary pollution to the environment such as surface water and groundwater; (3) The price of artificial chemical chelating agents is relatively high, and the cost of phytoremediation will inevitably increase in large-scale promotion and application

At present, scholars at home and abroad have carried out research on the accumulation of heavy metals in plants by different types and forms of fertilizers, but the laws of their effects are not consistent.

Most of the results found that insoluble phosphate fertilizers such as phosphate rock powder and calcium magnesium phosphate fertilizer have a passivation effect on heavy metals in the soil, and the application of phosphate fertilizers reduces the availability of heavy metals in the soil and limits the absorption of plants.

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