Controlled release of granular fertilizer using chitosan coating

Abstract

Effects of concentration and degree deacetylation of chitosan solution on released rate of chitosan coated fertilizer was investigated in this study. Concentrations of chitosan solution are 1%, 2%, 3% by weight dissolved in 1 m. acetic acid solution. Degrees of deacetylation of chitosan are 79% and 95%. The effect of different amount of nutrient elements on the release rate was also studied. The fertilizer was coated with chitosan solution in a coating drum and dried at 75ํC for 24 hours. Coated fertilizer was put into deionized water and, at a specified period, water solution was analyzed for amounts of nitrogen, phosphorus, and potassium. The results showed that amounts of nitrogen, phosphorus, and potassium released from coated fertilizer were less than the uncoated one. The release rate depends on concentration of chitosan solution and degree of deacetylation. The fertilizer coated with high concentration of chitosan solution has low release ratewhile fertilizer coated with chitosan having low degree of deacetylation also has low release rate. The release rate observed in this study depends on amounts of nutrient elements in the fertilizer