PROPERTIES AND NUTRITION RELEASE RATE IN THE SOIL OF SLOW-RELEASE POTASSIUM FERTILIZER VIA POLYMER COATING LAYER

Abstract

A slow-release potash fertilizer was prepared by coating polyacrylamitde onto granular potash fertilizer, which could minimize nutrient loss. Granular potash has been synthesized from conventional K₂SO₄, bentonite and polyacrylamitde. The structure and nutrient release characteristics of it via polyacrylamide coating layer were investigated by FTIR, TGA and EDX. The results revealed that the sample with mass ratio of  K₂SO₄ : bentonit : polyacrylamitde of 80:20:0,25, coating layer of  about 1% of polyacrylamitde released 81,25% potash in soil, in 7 weeks. The kinetic study showed that the potash release rate from the granular slow-release potash fertilizers  could be represented by pseudo-first-order equation at 25⁰C with R² ~1.