MULTI-COATING-STRUCTURE CONTROLLED-RELEASE FERTILIZER AND PREPARATION METHOD THEREFOR

摘要

Disclosed are a multi-coating-structure controlled-release fertilizer and a preparation method therefor, which relate to the field of fertilizers. The multi-coating-structure controlled-release fertilizer comprises fertilizer layers and coating layers which are coated layer by layer, wherein the fertilizer layers and the coating layers are arranged in a spaced manner, at least two fertilizer layers are provided, at least one coating layer is provided, and one of the fertilizer layers is used as a core of the fertilizer; the fertilizer layer contains at least one of a nitrogen fertilizer, a phosphatic fertilizer and a potassic fertilizer, and the coating layer is a polyurea formaldehyde, wherein the polyurea formaldehyde at least contains a polyurea formaldehyde having 2-5 carbon atoms. Elements such as nitrogen, phosphorus, potassium, calcium, magnesium and zinc in the fertilizer can be controlled better to release so as to meet the demands of different crops for different nutrients in different stages of growth. The controlled-release fertilizer is prepared by means of a reaction kettle, a slurry tank, a dusting groove and accessory facilities thereof, and the amount of fertilizer in each layer and the positions at which the fertilizer is coated in whole fertilizer particles can be controlled according to a design program. The whole process can be carried out intermittently, and can also be carried out continuously, and the fertilizer can be produced on a large scale.