Slow-release urea fertilizer from sulfur, gypsum, and starch-coated formulations

Abstract

To address nitrogen (N)-related environmental pollution, development of an economical, slow-release urea fertilizer is the need of the hour. A study was conducted on the reduction of nitrogen released from granular urea fertilizer by applying sulfur, gypsum, bentonite, and starch as coating material. Paraffin wax was used as a binder. The dissolution rates were studied by changing the composition of coating mixture using high-performance liquid chromatography. SEM was used to study the morphology of coated urea in terms of smoothness and uniformity. The ultraviolet spectroscopy analysis further authenticated the release behavior of coated urea in terms of nitrogen concentration. Coating material reduced the release rate of nitrogen from urea fertilizer, significantly. Mixture of sulfur and gypsum coating on urea gave slowest release rate of nitrogen from urea fertilizer, i.e., 37%, as compared to uncoated urea and thus seems to be the most promising binding material for product development.

Keywords:

• coated urea
• dissolution rate
• slow-release fertilizer
• sulfur coating

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project of was jointly funded by Higher Education Commission Pakistan and Fuji Fertilizer Company under University Industry Technological Support Program (HEC Project No: UITSP/HEC/2014/1-51).