Synthesis and Characterization of Calcium Based Coating Materials for Slow Release of Urea

Abstract

The food crises are increasing with the increasing population in the world. Artificial fertilizers are being used to overcome the gap of food scarcity between demand and supply. Urea is an important fertilizer being nitrogen-rich in contents. Nitrogen losses are a major problem affecting the efficiency of the urea. Coatings can be used to overcome the release problems of the urea. Calcium phosphate, Gypsum Power and Calcium Nitrate were coated separately and along gelatin as a binder to study the effect of slow release on nitrogen from urea. Scanning Electron Microscopy was used to study the structure of the coatings. Fourier Transformed Infrared Spectroscopy and X-Ray Diffraction were used to detect the presence of urea bonds and making sure that no chemical reaction occurred, and coatings were only physical. Universal Testing Machine was used to detect the crushing strength of the coated urea samples. Slow release analysis was performed to determine the nitrogen release pattern of the urea. The slow release of nitrogen was tested in water and soil and values were determined by UV-Spectroscopy. Calcium Nitrogen along gelatin gives the best results among all in both water as well as soil. The release of calcium nitrate along gelatin as coating gives 220% better results than the uncoated urea. A blank and 8 coated urea samples were used with 3 repetitions in a Complete Random Design (CRD) on sorghum plants. Different parameters were tested before and after experiments from soil, roots and shoots of the plants. The pH and Electric Conductivity (EC), and Microbial Biomass Potassium remained unchanged and had no effect by the applications of different coatings. Calcium Nitrate show the best results in Organic Matter (15350.9 ± 154.88 Kg ha-1), Microbial Biomass Carbon (2.836 ± 0.024 Kg ha-1) and Microbial Biomass Nitrogen (1.452 ± 0.0425 Kg ha-1).