COMPOSITION WITH SUSTAINED-RELEASE OF FERTILIZER AND METHODS OF THEIR PREPARING Russian patent published in 2002 - IPC

FIELD: fertilizers. SUBSTANCE: invention relates to fertilizers with sustained-release of nutrient substances and to methods of their preparing. Invention proposes composite with sustained-release of fertilizer comprising granulated core containing at least one water-soluble fertilizer. Fertilizer granules show smooth external surface being at least 95% of these granules show spherical form and practically water-insoluble cover applied on granulated pithy material. Fertilizing composite is structured by method to provide the combined release of fertilizing substance in the amount less 10% of its total weight in granulated core for 30 days after effect with moisture on fertilizing composite. Composite comprises of a single layer of homogeneous continuous polymeric film presenting on at least 90% of granulated pithy material. Invention proposes also method of fertilizing composite preparing. Fertilizer is characterized by delayed onset of release of nutrient substance. EFFECT: improved properties of composite and method of preparing. 13 cl, 4 dwg