Assessment of nutrient release from slow-release compound fertilizers by ion exchange resin membrane technique

摘要

Ion exchange resin membrane (IERM) method was used to study the N, P and K release characteristics of two slow-release-compound fertilizers (SRCFs) at 25°C in soil. The relationship between nutrient release of SRCFs and nutrient uptake by rice was studied in a pot experiment. Results showed that N and P from SRCFs were released slowly, compared to the common compound fertilizer (CCF) in soil during an incubation period of 56 days. The dynamic characteristics of N, P, and K release in soil could be quantitatively described by the Elovich, double constant, parabola diffusion and first-order diffusion equations (r = 0.70~*-0.999~(**)). There were positive correlations between N, P, and K release from SRCFs, determined by the IERM technique, and N, P, and K uptake by rice in the pot experiment (r = 0.869~*-0.994~(**)).