Slow Release Fertilizer Prepared from Leonardite and Zeolite

Abstract

This research aims to develop slow release fertilizers by using Leonardite and Zeolite. Two formulations of slow release fertilizer were prepared namely the Leonardite and Zeolite slow release fertilizer and the Leonardite slow release fertilizer. Theirnutrient releasing rates were investigated and comparedwith that of the commercially availableslow release fertilizer which contained N8:P24:K24.Specifically the slow release fertilizers were formulated from leonardite, zeolite and other fertilizer materials such as ammonium phosphate and potassium chloride. Each formulation was then pelletized and baked at 100°C for 1 hr to remove water; then they were kilned at 150°C for 1 hr. All the kilned fertilizers were analyzed subsequently by using the Fertilizer Test Kit (KU.5) to determine the releasing rates of the main N, P and K nutrients. Each fertilizer was immersed in distilled water and shakenat the speed of 150 rpm for 10 min, 30 min, 1 hr and 2 hr. The nutrients released into the distilled water were determined following the standard methodology. The results indicated that the nutrient releasing rates of the slow release fertilizer prepared from Leonardite and Zeolite were less than those observed in the commercial fertilizer.