Nitrogen-phosphorus-potassium full-slow-release fertilizer, preparation method and application method thereof

Abstract

The invention provides a nitrogen-phosphorus-potassium full-slow-release fertilizer, a preparation method and an application method thereof. The nitrogen-phosphorus-potassium full-slow-release fertilizer comprises (a) MgNH4PO4.6H2O and (b) at least one substance selected from a KAlSiO4 crystal, a K2O-Fe2O3-SiO2 system crystal, a K2O-CaO-SiO2 system crystal, a K2O-MgO-SiO2 system crystal and a glass body containing potassium and silicon. The nitrogen-phosphorus-potassium full-slow-release fertilizer takes potassium-containing rock as a main raw material and is processed through the steps of rawmaterial blending, raw material heating, compounding reaction and the like. The invention also discloses application of the nitrogen-phosphorus-potassium full-slow-release fertilizer as a shell for coating a slow-release fertilizer, and an application method of the nitrogen-phosphorus-potassium full-slow-release fertilizer. The nitrogen-phosphorus-potassium full-slow-release fertilizer has the beneficial effects that (1) nutrition elements are rich and can be stably and continuously supplied; (2) the nutrient release period is controlled; (3) the leaching loss rate is low, and the nutrient utilization rate is high; and (4) soil acid-base balance can be adjusted, and soil properties can be improved.

Description

technical field [0001] The invention relates to a full slow-release fertilizer, in particular to a nitrogen, phosphorus and potassium full slow-release fertilizer, a manufacturing method and an application method thereof, and belongs to the technical field of fertilizers. Background technique [0002] At present, the apparent utilization rate of fertilizers in my country is generally low. The reason for this phenomenon is not only the subjective factors of unreasonable application of fertilizers and the objective factors of poor fertilizer retention capacity of the fertilized soil, but also the fundamental reason is the nature of the fertilizer itself. - Low utilization rate due to high mobility caused by high activity (including water solubility and volatility), especially nitrogen and potassium fertilizers. Commonly used nitrogen-containing fertilizers include urea, ammonium nitrate, ammonium chloride, diammonium phosphate, monoammonium phosphate, and the like. Commonly us...

AI Technical Summary

Problems solved by technology

This type of slow-release fertilizer does realize the slow release of fertilizer, but there are also problems: (1) most of the organic polymers used as coating agents are difficult to degrade, and a large amount of application will cause soil degradation and ecological hazards; (2) this type of fertilizer The encapsulation agent is wrapped on the surface of the fertilizer and controls the dissolution and release of nutrients by limiting the contact area between fertilizer particles and water. However, the control mechanism is single, and it will not be released quickly because of the strong nutrient demand of the crops, nor will it be released slowly because of the low nutrient demand of the crops. Inconsistent with the characteristics of crop fertilizer requirements

However, sewage is often rich in nitrogen and phosphorus but lacks magnesium, and struvite crystallization requires a higher pH

Therefore, the struvite crystallization process needs to add magnesium source and alkali source, which greatly reduces the economic feasibility of struvite crystallization to recover nitrogen and phosphorus.

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