Cadmium-lowering composite fertilizer and application method thereof

Abstract

The invention relates to a cadmium-lowering composite fertilizer and an application method thereof. The cadmium-lowering composite fertilizer comprises a deep applied fertilizer and a surface appliedfertilizer; the deep applied fertilizer and the surface applied fertilizer are separately one of the following fertilizers and are different from each other: a positive colloid fertilizer is used forgenerating positively charged colloid so that the electrical property of the surface of silty clay activated by chloride ion becomes positive from negative; and a negative colloid fertilizer is used for generating negatively charged colloid so that hydroxide which is passivated and contains cadmium heavy metal is combined to oxide to form iron-manganese nodules which are settled to the lower layerof soil. The invention provides a core idea of a cadmium-lowering technology, namely cadmium is forced not to be compatible to the soil, thus, a soil plough layer becomes a derichment layer from an enrichment layer, the cadmium can be automatically separated from the soil plough layer, and permeates into a subsoil layer along with permeation of the water, the problem of cadmium pollution of the soil is solved, a purpose of lowering the cadmium by using a fertilizer is achieved, the cost for fertilizer application is not increased, the cadmium is lowered to reach the standard fundamentally, and a purpose of seeking both temporary and permanent solutions is achieved. The cadmium-lowering composite fertilizer has the advantages of low cost and stable cadmium-lowering technology, production is maintained in a cadmium lowering process, and the cadmium-lowering composite fertilizer is easy to popularize.

Description

technical field [0001] The application relates to the field of reducing cadmium, in particular to a compound fertilizer for reducing cadmium and its application method. Background technique [0002] The inventors have found that the enrichment of soil cadmium in the cultivated layer is related to the cadmium interception of water and air flowing through the cultivated layer in the front-line work of farmland with more than 30 years of experience. Usually, the cadmium concentration in the water flowing into the paddy field is lower than 0.005 mg / L. If the soil does not have a cadmium enrichment mechanism, even if the cadmium in the irrigation water source exceeds the standard by 50 times, the soil cadmium content will not exceed the standard. Therefore, the excess of cadmium in the soil is firstly determined by the ability of the soil to absorb and hold cadmium. That is to say, the soil chemical mechanism of cadmium enrichment is formed first, and then the pollutants exceed ...

AI Technical Summary

Problems solved by technology

After the 1980s, due to the application of a large amount of chemical fertilizers containing chloride ions to the soil, the soil that was originally anti-enriched for cadmium became positively enriched, and the tendency of cadmium enrichment was reversed, which led to the problem of excessive cadmium in crops

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