Fixation of urea to polyacrylic acid and nitrogen release behavior of the product (polyurea) - A comparison with urea and control (without nitrogen fertilizer)

Abstract

A slow-release nitrogen fertilizer was prepared by covalently immobilizing urea on a biodegradable acrylic acid based polymer matrix. Polyacrylic acid was prepared by solution polymerization of acrylic acid followed by covalent immobilization of urea through the activated carboxyl groups. The resulting product, termed as polyurea, was characterized by FTIR and NMR spectral analyses, thin layer chromatography measurement and elemental analyses. Results showed that polyurea contained 24.76% nitrogen and the solvency reduced to over 300 times as compared to urea. To clarify the performance of this polyurea in agriculture, a comparative study was then carried out on the growth of green chili Capsicum annuum plants using urea and control (no nitrogen fertilizer) as the basis. Polyurea showed improved yield in terms of average plant size over the cultivation period. The nitrogen release behavior in soil during cropping and plant uptake of nitrogen suggested that polyurea can be used as slow-release nitrogen fertilizer. © 2009 Asian Network for Scientific Information.