SLOW-RELEASE COATED FERTILIZER USING OYSTER SHELLS AND PREPARATION THEREOF

PURPOSE: A slow-release fertilizer, being coated with chitosan, using oyster shells is provided, which improves quality of agricultural products, and has effects of antibiotics, activation of growing plants and acceleration of calcium(Ca) absorption. CONSTITUTION: The preparation method of slow release fertilizer comprises the steps of: preparing Ca-chelated oyster shell powder by sintering shells at 800-1200deg.C for 3-4hrs., and cooling; adding 40-80wt.% of shell powder, 1-15wt.% of amino acid, 5-20wt.% of nitrogen(N-NO3, N-NH3), 5-20wt.% of P2O5, 5-20wt.% of K2O, 0.01-1wt.% of B2O3, 0.1-5wt.% of MnO, 0.1-5wt.% of Fe, 0.001-0.1wt.% of microbes(photosynthetic bacteria:Rhod bact.) and 0.5-1wt.% of plant extracts such as small amount of Mg, I, Fe, Ca, fiber, etc.; mixing and forming to a shape of ball; and coating with chitosan by spraying.