Water content management method for lowering content of chromium in rice in mild chromium-polluted paddy field

Abstract

The invention discloses a water content management method for lowering the content of chromium in rice in a mild chromium-polluted paddy field. The method comprises the following steps of 1, adopting water flooding irrigation from a rice growth returning stage to the early stage of tillering; 2, conducting natural drying in the later stage of rice tillering, and maintaining the water content of soil at 35%-40%; 3, adopting water flooding irrigation in a rice booting stage, a head sprouting blossoming stage and a grain filling phase; 4, conducting draining and field drying and maintaining the water content of soil at 30%-35% in a rice mature stage till the rice is mature and harvested. According to the water content management method for lowering the content of chromium in rice in the mild chromium-polluted paddy field, the key phase when metal chromium enters rice is grasped, the water content management is effectively implemented, by changing the valence state and the form of chromium in the soil, the absorption and accumulation of chromium by rice are lowered, and thus the content of chromium in the rice is lowered. It is measured that the content of chromium in the rice planted according to the method conforms to a national health standard.

Description

technical field [0001] The invention relates to the technical field of chromium pollution treatment in paddy fields, in particular to a water management method for reducing the chromium content of rice in paddy fields with moderate to light chromium pollution. Background technique [0002] With the development of industry, chromium and its compounds are used more and more, such as electroplating, leather, printing and dyeing, chemical industry and other industries. In my country, about 750,000 to 900,000 tons of chromium-containing waste residues are produced every year, of which less than 17% have been treated and comprehensively utilized. According to the "Zhejiang Provincial Heavy Metal Pollution Comprehensive Prevention and Control Plan (2010-2015)", the total discharge of chromium accounts for 95% of the total industrial heavy metal discharge in Zhejiang Province. Chromium has become an important heavy metal pollutant in the environment. [0003] Rice is the main food...

AI Technical Summary

Problems solved by technology

Alternate wet and dry irrigation is generally used in rice cultivation at present, but this method is not suitable for chromium-contaminated paddy fields, which will lead to an increase in the bioavailability of chromium in the soil, thereby increasing the absorption and accumulation of chromium in rice

Some also use full flooding treatment, but at present, agricultural water resources are extremely scarce, and it is impractical to require flooding during the entire growth period, and it will also cause many ineffective tillers, affecting yield, and is not conducive to mechanized harvesting

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