Compound fertilizer capable of reducing cadmium and lead contents in slightly-polluted farmland corn and preparation method thereof

Abstract

The invention discloses a compound fertilizer capable of reducing cadmium and lead contents in slightly-polluted farmland corn and a preparation method thereof. The compound fertilizer is prepared by urea, ammonium chloride, ammonium sulfate, ammonium nitrate, diammonium phosphate, phosphorus-potassium nitrate fertilizer, calcium magnesium phosphate fertilizer, potassium chloride, zinc sulfate, agricultural nitric acid rare earth, sepiolite, kaolin, bentonite and power plant furnace slag in proportion. The preparation method includes the following steps: A. preparation of the sepiolite; B. preparation of the kaolin; C. preparation of the bentonite; D. preparation of the power plant furnace slag; and E. mixing raw materials prepared in the steps with the urea, the ammonium chloride, the ammonium sulfate, the ammonium nitrate, the diammonium phosphate, the phosphorus-potassium nitrate fertilizer, the calcium magnesium phosphate fertilizer, the potassium chloride, the zinc sulfate and the agricultural nitric acid rare earth, and processing the mixture into the compound fertilizer. The invention can effectively reduce active cadmium and lead in soil as well as the cadmium and lead contents in corn, and enable the active cadmium and lead contents in soil of slightly-polluted farmland to be reduced by 48.8-54.2% and 38.1-44.7% respectively, and the cadmium and lead contents in the corn to be reduced by 44.3-49.3% and 43.4-45.4% respectively. The invention is suitable for being generalized in vast 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 lightly polluted farmland corn, and also relates to a compound fertilizer for reducing the cadmium and lead content of lightly polluted farmland corn. The preparation method of the mixed fertilizer is suitable for corn production in areas polluted by heavy metals, especially in areas polluted with mild cadmium and lead. 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 was only 2.67 million hm 2 , increa...

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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 farmland.

There are three reasons: first, the quality and safety of agricultural products caused by mildly polluted farmland 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 (at least 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; third, the definition of lightly polluted farmland is difficult to grasp in actual operation

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