Phytoremediation method for restoring farmland soil heavy metal cadmium pollution

Abstract

The invention discloses a phytoremediation method for restoring farmland soil heavy metal cadmium pollution. The phytoremediation method comprises the following steps: selecting a rice variety Meilianzao, planting the rice variety in the heavy metal cadmium polluted soil according to a conventional planting method of rice, draining the water and sunning the farmland from the booting stage to the pustulation stage and the milk ripening stage, so as to enable the heavy metal cadmium in the soil to be adsorbed in rice straws and rice through planting. The cadmium content in the soil can be effectively lowered by planting the rice variety Meilianzao in the farmland with cadmium exceeding the standard, draining water and sunning the farmland from the booting stage to the milk ripening stage, and enabling the heavy metal cadmium in the soil to be adsorbed by and transferred to the rice. The technical support is provided for restoring the soil cadmium pollution and ensuring the aftercrop food safety. The method is simple and feasible and easy to grasp by farmers; the harvest can be purchased from the farmers, so that the secondary pollution can be avoided.

Description

Technical field: [0001] The invention belongs to the field of farmland soil heavy metal cadmium pollution control, and in particular relates to a phytoremediation method for repairing farmland soil heavy metal cadmium pollution. Background technique: [0002] For heavy metal contaminated soils, phytoremediation has been considered to have the advantages of environmental friendliness and low cost. At present, there are more than 400 kinds of super-accumulating plants in the world, but there are very few super-remediating plants for cadmium. The super-remediating plants have small biomass, long repairing period, shallow root depth, and are not suitable for excessive pollution concentration or multiple pollution. Adaptability, not suitable for the disadvantages and limitations of polluted soil characteristics and climate, etc. At the same time, many super-accumulative plants are mostly obtained from the wild environment, lacking a complete set of agricultural management and mea...

AI Technical Summary

Problems solved by technology

At present, there are more than 400 kinds of super-accumulating plants in the world, but there are very few super-remediating plants for cadmium. The super-remediating plants have small biomass, long repairing period, shallow root depth, and are not suitable for excessive pollution concentration or multiple pollution. Adaptability, not suitable for the disadvantages and limitations of polluted soil characteristics and climate, etc. At the same time, many hyperaccumulative plants are mostly obtained from the wild environment, lacking a complete set of agricultural management and measures

[0003] It has been recognized that there are huge differences in the absorption of heavy metals among crop varieties. Rice is the most important food crop in the world, especially in Asian countries such as Japan and China. Heavy metal accumulation varieties are used to ensure food production safety in low and medium heavy metal pollution areas. However, since the absorption of heavy metal cadmium by rice is deeply affected by soil moisture management, many low-cadmium rice varieties are difficult to achieve the expected results in practical applications. For this reason, Japan The researchers did the opposite, by looking for high-accumulation varieties of cadmium, using these varieties to repair cadmium-contaminated soil, and achieved remarkable results. They found two high-accumulation varieties, Milyang23 and Chokoukoku. During the two-season planting, Chokoukoku The cadmium content in the aboveground part of the rice can be as high as 70mg kg-1 (the standard for hyperaccumulative plants is 100g kg-1) rice can remove cadmium from cadmium-contaminated soil (1.63mgkg-1) respectively (550 and 333g ha-1 extract a total of 883g Cd ha-1), reducing cadmium in soil by 38%

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