Combined cadmium reducing method for rice through basal application of passivating agent for activity degradation and topdressing of iron fertilizer for root control in tillering stage

Abstract

The invention provides a combined cadmium reducing method for rice through basal application of a passivating agent for activity degradation and topdressing of an iron fertilizer for root control in atillering stage. The method comprises the following steps: before planting of rice, carrying out basal application with basic passivating materials like lime with an application amount of 100 to 300kg / mu; and in the early tillering stage of the rice, maintaining soil to be in a semihumid state, uniformly applying the iron fertilizer with an application amount of 7.5 kg / mu into the soil, and in 2d after fertilizer application, carrying out waterlogging to a rice milk ripeness stage or later. The method provided by the invention integrates reduction of cadmium activity of the soil by application of the passivating agent and reinforcement of cadmium-resistant effect of an iron film on the root surface of the rice by topdressing of the iron fertilizer into a whole. Compared with contrast and independent basal application of the lime, independent topdressing of the iron fertilizer and mixed basal application of the lime and the iron fertilizer, the combined cadmium reducing method provided by the invention respectively reduces the cadmium concentrations of brown rice by 74.6 to 75.4%, 52.6 to 57.1%, 66.7 to 69.4% and 45.5 to 51.6% for acid soil with moderately and mildly over-standard cadmium.

Description

technical field [0001] The invention relates to the technical field of safe production of moderately and lightly polluted farmland, in particular to the safe production technology of rice in moderately and lightly polluted farmland with cadmium. Specifically, it is a combined method for reducing cadmium by applying passivation agent deactivation in rice base and topdressing iron fertilizer root control in tillering stage. Background technique [0002] Cadmium pollution in farmland directly threatens the quality and safety of agricultural products in my country and the sustainable development of agriculture, such as the cadmium rice incident in Guangdong, Hunan and other places. In view of the characteristics of low cadmium pollution, large area and agricultural use of farmland in my country, it is urgent to develop efficient, economical, fast, simple, reproducible and easy-to-promote safe farmland utilization technologies. At present, there are many studies on the treatment...

AI Technical Summary

Problems solved by technology

However, under the condition of increasing the pH with the application of alkaline passivator, the formation of iron film on the root surface of rice and its effect on preventing cadmium will be weakened. 2+ Concentration drop is one of the key factors, even with a small amount of Fe added to the passivator 2+ , due to the strong alkalinity of the passivator, the effectiveness of iron is also very low

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