Studying and preparation slow-realease fertilizer based the on clay and modified-starch

Abstract

Show-release fertilizers based on bentonite and modified-starch have been prepared and studied. Tapioca Starch was modified by Javen solution at diffirent rime conditions, in neutral medium. The degree oxidÌ2:ation of Starch was determined by carboxyl index and molecular weight. After that, modified-starch was mixtured with ure fertilizer, bentonite before pelleting. The release rate and nutrient content of the products were characterized. The results showed that modifred-starch samples after 7 hours for the best adhesive ability, optimum starch content of slow release fertilizer composition is 30 % by weight compared with bentonite.