Silicon applying method for reducing content of mercury of rice grains in rice fields severely polluted by mercury

The invention relates to a silicon applying method for reducing the content of mercury of rice grains in rice fields severely polluted by mercury, and belongs to the technical field of prevention and control of heavy metal pollution of agricultural products. The silicon applying method is characterized in that in a rice field severely polluted by mercury (Hg concentration of soil is 2 mg/kg and is four times greater than the national limitation standard), the total silicon application amount is 300 kg/hm (counted by the effective ingredient SiO2), the silicon is applied in three steps, silicon of which the amount is 1/2 of the total silicon amount is applied five days before transplanting of rice seedlings, silicon of which the amount is 1/4 of the total silicon amount is applied 30 days after transplanting of the rice seedlings, and silicon of which the amount is 1/4 of the total silicon amount is applied 5 days after earing. Silicon application 5 days before transplanting of the rice seedlings and silicon a