Method for reducing content of cadmium in middle rice

Abstract

The invention discloses a method for reducing the content of cadmium in middle rice. The method includes the following steps that after middle rice of the first year is harvested, middle rice straw is returned to the field directly, and tillage is conducted so that the middle rice straw can be evenly mixed with soil; hyperaccumulation plants are planted in a paddy; after the hyperaccumulation plants are removed from March to May in the second year, soil heavy metal passivator is scattered on the surface of soil of the paddy; tillage is conducted, and base fertilizer is applied 3-5 days later; tillage is conducted, and rice is transplanted; during planting of rice, a foliar resistance control agent is sprayed in the later tillering stage and the booting stage of rice respectively, wherein spraying time interval is 5-10 days; field drying is conducted in the later tillering stage, natural drying is conducted in the maturation stage, and flooding irrigation is conducted in other development stages. According to the method, crop production and straw resource utilization are not affected, the dual targets of reducing the paddy soil cadmium content and reducing the rice cadmium content are achieved under the combined action of plant extraction, soil passivation, foliar resistance control and water management, and effects are more remarkable compared with other combination technologies.

Description

technical field [0001] The invention relates to a method for reducing cadmium content in mid-season rice, and belongs to the technical field of prevention and control of heavy metal pollution of agricultural products. Background technique [0002] In recent years, due to sewage irrigation, application of pesticides and fertilizers, mining and vehicle exhaust emissions, the situation of heavy metal pollution in cultivated land soil in my country has become increasingly severe. In 2014, the National Soil Pollution Bulletin showed that there were 50 million mu of moderately and severely polluted cultivated land in the country, and the rate of soil points exceeding the standard in cultivated land was as high as 19.4%, among which cadmium (Cd) pollution was the most prominent, and the rate of sample points exceeding the standard reached 7.0%. The Cd content in the medium has exceeded 14.6×10 8 kg, food security problems caused by Cd pollution are not uncommon every year. Howeve...

AI Technical Summary

Problems solved by technology

[0006] At present, the technologies used for the remediation of cadmium pollution in paddy fields mainly include plant extraction and chemical passivation, but these two technologies are rarely used in combination

Planting hyperaccumulator plants can reduce soil total Cd content, but if phytoextraction is used in double-cropping rice, it will affect rice production

Although chemical passivation technology can reduce the Cd content of rice by reducing the activity of soil Cd, thereby reducing the absorption of Cd by rice, and can temporarily solve the problem of cadmium rice, but it has no significant effect on the reduction of total Cd in soil, and has no effect on soil restoration. play a permanent role

Images