Compound fertilizer capable of reducing cadmium lead content of vegetables in slightly contaminated vegetable field and preparation method thereof

Abstract

The invention discloses a compound fertilizer capable of reducing cadmium lead content of vegetables in a slightly contaminated vegetable field and a preparation method thereof. The compound fertilizer is prepared from urea, ammonium chloride, ammonium nitrate, diammonium phosphate, a nitric phosphate potassium fertilizer, a calcium magnesium phosphate fertilizer, potassium chloride, sepiolite, kaolin, bentonite and power plant slag in a ratio. The preparation method for the compound fertilizer comprises the following steps of: A, preparing the sepiolite; B, preparing the kaolin; C, preparing the bentonite; D, preparing the power plant slag; and E, mixing the raw materials prepared in the steps A, B, C and D with the urea, the ammonium chloride, the ammonium nitrate, the diammonium phosphate, the nitric phosphate potassium fertilizer, the calcium magnesium phosphate fertilizer and the potassium chloride in the ratio, and performing production processing to prepare the compound fertilizer. The compound fertilizer is mainly characterized by comprising 36.5 to 43.5 percent of passivator which can effectively reduce active state cadmium lead content of soil and cadmium lead content of the vegetables, and 30 percent of nutrients of nitrogen, phosphorus and potassium, so that the active state cadmium and lead contents of the soil in the slightly contaminated vegetable field are reduced by 41.3 to 52.3 percent and 36.0 to 58.5 percent respectively, the cadmium content and the lead content of vegetable products are reduced by 30.1 to 52.8 percent and 27.9 to 51.0 percent respectively, and the compound fertilizer is suitable to be popularized and applied to many heavy metal contaminated areas.

Description

technical field [0001] The invention belongs to the technical field of agricultural environment conservation and restoration, and more specifically relates to a compound fertilizer that can effectively reduce the cadmium and lead content of vegetables in lightly polluted vegetable fields, and also relates to a method for reducing the content of cadmium and lead in vegetables in lightly polluted vegetable fields The preparation method of the compound fertilizer is suitable for the vegetable production in the vast heavy metal polluted areas, especially the mild cadmium and lead polluted areas. Background technique [0002] With the continuous advancement of industrialization and urbanization, the problem of heavy metal pollution in my country's soil has been paid more and more attention by people. According to relevant reports, in the early 1980s, the area of ​​cultivated land polluted by heavy metals such as cadmium, lead, mercury, arsenic, chromium, and nickel in my country ...

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Problems solved by technology

However, there are very few reports on the application of soil heavy metal passivators such as sepiolite, calcium magnesium phosphate fertilizer, and kaolin in lightly polluted vegetable fields.

There are three reasons: first, the quality and safety of agricultural products caused by lightly polluted vegetable fields has not attracted widespread attention; second, the current soil heavy metal passivation technology is basically a one-time reserve application technology, that is, a one-time large-scale application (less Then hundreds of kilograms, as many as 2-3t) soil heavy metal passivation agent, because the cost is too high, farmers are not easy to accept; the third is that the definition of lightly polluted vegetable fields is difficult to grasp in actual operation

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