Method for safe production while lossless in-situ remediation of moderately and mildly cadmium-polluted farmland soil

Abstract

The invention discloses a method for safe production while lossless in-situ remediation of moderately and mildly cadmium-polluted farmland soil. According to the method, rice and sesbania are planted in an intercropping mode, and 1-2 rows of sesbania are intercropped every 3-4 rows of rice; a nitrogen-phosphorus-potassium compound fertilizer and an organic fertilizer are dressed for promoting the growth of rice and sesbania; in the remediation period, the water content of the field soil is kept at 70%-100%; and after the rice is mature, the rice and sesbania are harvested at the same time. According to the method, the yield of rice can be stable or obviously increased, the cadmium content in grains is lower than the national food safety standard, meanwhile, efficient extraction of cadmium from sesbania is promoted, and thus the purpose of safe production while lossless in-situ remediation is achieved. The method does not need additional additives, does not destroy the soil structure and composition, does not cause secondary pollution, has the advantages of wide applicability, high efficiency, small engineering quantity, short treatment period, low cost and the like, and is suitable for treating the moderately and mildly cadmium-polluted farmland soil.

Description

technical field [0001] The invention belongs to the technical field of heavy metal polluted soil treatment. Specifically, it relates to a method for safe production while non-destructive in-situ restoration of medium-light cadmium-contaminated farmland soil. Background technique [0002] Soil heavy metal pollution refers to human activities, the content of trace harmful elements in the soil exceeds the background value, and the excessive content caused by excessive deposition is collectively referred to as soil heavy metal pollution. The heavy metals that pollute the soil mainly include mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr) and metalloid arsenic (As) and other elements with significant biological toxicity, as well as zinc (Zn) and copper with certain toxicity. (Cu), nickel (Ni) and other elements. Heavy metal pollution in soil mainly comes from pesticides, wastewater, sludge and atmospheric deposition, etc. For example, mercury mainly comes from mercury-cont...

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Problems solved by technology

[0005] Chinese patent document CN101780466A discloses a method for using leguminous shrubs to restore heavy metal cadmium-contaminated soil. The method mainly involves planting Cassia pterygium plants in heavy metal cadmium-contaminated soil, and adding EDTA as a strengthening agent to the soil, and EDTA as a Chemical complexing agents have been proved to have obvious effects, but the secondary pollution problem caused by them cannot be effectively solved; moreover, although Cassia pterygium has a large biomass and a high ability to absorb cadmium, its individual height and growth cycle Long, it will hinder the normal growth of rice, and it is not suitable for intercropping or crop rotation with rice; moreover, Cassia pterygium is not suitable for planting in paddy fields

Plant fixation can effectively reduce the mobility and bioavailability of pollutants, but it does not remove the pollutants fundamentally, and once the environmental conditions change, it will cause pollution again

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