Method for repairing heavy metal polluted soil of farmland with combination of crop rotation of grassiness and fungus

Abstract

The invention belongs to an elephant grass-mushroom fungus crop rotation combined recovery technique for heavy metal polluted soil of farmlands in the technical field of resources and environment, which comprises the following steps: elephant grasses and mushroom fungi are planted by means of crop rotation on the polluted farmlands to enrich heavy metal ions in the soil; when the elephant grasses and the mushroom fungi in the treated lands are mature, the elephant grasses and mushroom fungi are harvested respectively and thrown into a biogas tank according to a specific proportion of the elephant grasses and mushroom fungi for bio-decrement and fermentation production of biogas; a biogas liquid undergoes chemical precipitation, and the heavy metal ions in the biogas liquid are removed; and deposits and biogas residues are accumulated and buried. The elephant grasses have the characteristics of strong capacity of enriching the heavy metal ions, large biomass and promotion of the growth of the mushroom fungi; the mushroom fungi have the characteristics of strong capacity of enriching the heavy metal ions, short growth cycle and easy after-treatment; when the elephant grasses and the mushroom fungi are combined to recover the heavy metal polluted soil, high recovery efficiency can be achieved; the chemical precipitation method in the subsequent treatment can eliminate heavy metal environmental pollution fundamentally; and the overall recovery effect of elephant grass-mushroom fungus crop rotation combined recovery technique is as follows: 15 to 30 percent of polluted heavy metals in cultivated horizons of the farmlands are removed each year.

Description

Technical field: [0001] The invention belongs to the technical field of resources and environment, and in particular relates to a method for joint crop rotation of elephant grass and several kinds of mushrooms to repair farmland heavy metal polluted soil. Background technique: [0002] The development of industry and agriculture and the acceleration of urbanization have made the problem of soil heavy metal pollution increasingly prominent, including cadmium (Cd), lead (Pb), chromium (Cr), mercury (Hg), arsenic (As), nickel (Ni), copper (Cu), zinc (Zn) and so on are more common heavy metals polluting. The global average annual emission of Hg is about 15,000 tons, Cu is 3.4 million tons, Pb is 5 million tons, Mn is 15 million tons, and Ni is 1 million tons, which seriously damages the ecological environment balance and the sound development of agricultural economy. [0003] At present, the farmland soil polluted by heavy metals in my country is about 2500×10 4 Hectares, as m...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to overcome the deficiency of plants and fungi for repairing heavy metal-contaminated soil alone, through the joint planting of elephant grass and fungus in rotation, improve the efficiency of biological associations in removing heavy metals from soil, and provide a method for on-site repair of heavy metal-contaminated farmland soil. Elephant grass-fungus joint restoration technology with short period, easy implementation, environmental protection and saving