ENHANCEMENT THE SLOW RELEASE PROPERTIES OF UREA-KAOLINITE FERTILIZER BY POLY(VINYL ALCOHOL) BINDER

Abstract

This study investigated the use of poly(vinyl alcohol) (PVOH) as a binder to prepare urea–kaolinite (U-K)
slow release fertilizer (SRF) granules. The concentration of PVOH was varied from 1.0 to 7.0% and it was
found that PVOH concentration of 4% and above was able to reduce urea release rate down to SRF
standards. Slow-release urea fertilizer based on PVOH and kaolinit was prepared and characterized. The
analysis of IR, SEM, XRD, EDX showed that the present of PVOH and kaolinite stabilized the structure of
fertilizer, slowed down the release of the Nitrogen in ure, led to the decreasing of the leakage. The results
showed that the slow-release fertilizer sample (U-K-PVOH) containing 40% urea and 4% PVOH binder
released only 43.21% of its N in water after 96 hours (at 25 OC).