An agronomic method for controlling cadmium and selenium enrichment in rice

Abstract

The invention provides an agricultural method for controlling cadmium and enriching selenium of rice. The method comprises the steps that soil is kept in a semi-humid state in the tillering stage of rice plants, selenium fertilizer is evenly applied into soil at 100 g / mu, and the rice plants are submerged with water two days after the fertilizer is applied until the rice plants are harvested. For intermediate-alkaline soil, and the cadmium concentration in brown rice can be reduced by 20.9%-26.5%, the selenium content can range from 0.083 mg / kg to 0.106 mg / kg and reaches the selenium enrichment standard with selenium higher than 0.04 mg / kg; for acid soil, the cadmium concentration in brown rice can be reduced by 38.0%-63.0%, the selenium content can range from 0.248 mg / kg to 0.283 mg / kg and reaches the selenium enrichment standard. By means of the method, the defects that selenium fertilizer is likely to be fixed by minerals of soil when applied as base fertilizer, consequently the biological effectiveness of selenium is reduced in the vigorous growth period of rice, the cadmium control effect is poor, and when selenium fertilizer is subjected to foliage spray, the cadmium control effect is poor when the spraying amount is small, and the selenium content of grains is too high to cause health risks when the spraying amount is large are overcome, and selenium-rich rice can be produced.

Description

technical field [0001] The invention relates to the technical field of safe production of medium and low-pollution farmland, in particular to the technology of safe production of rice in medium-low cadmium-polluted farmland. Background technique [0002] According to the National Soil Pollution Survey Bulletin on April 17, 2014, the excessive rate of heavy metal points in cultivated land in my country is 19.4%, mainly moderate and light pollution (18.3%). Cadmium is the primary pollutant to be controlled in farmland in the Southwest and Central South regions, as well as in the Yangtze River Delta, Pearl River Delta, Liaoning and Northwest regions (the national exceeding rate accounts for 7.0%). Cadmium pollution in my country's farmland directly threatens the quality and safety of agricultural products and the sustainable development of agriculture in my country, such as the cadmium rice incident in Guangdong, Hunan and other places. In view of the characteristics of low ca...

AI Technical Summary

Problems solved by technology

Na 2 SeO 3 When used as basal fertilizer and applied to the soil, the absorption and transport capacity of cadmium in the early growth stage of rice is limited, and in the critical period (tillering stage and later) when rice absorbs and transports cadmium, due to the Na 2 SeO 3 Most of the Se that has been fixed or transformed into other forms by soil minerals reduces the effect of controlling cadmium

If the amount of selenium fertilizer sprayed on the leaves is too low, the effect will not be significant; if the amount of selenium sprayed is too high, it will easily lead to excessive accumulation of selenium in the grain and cause health risks, and the effect will be unstable

At present, there is no report on soil application of selenium fertilizer to control cadmium and selenium enrichment in the tillering stage of rice in the literature

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