Preparation and Nutrient Release Mechanism of a Polymer as Slow-Release Compound Fertilizer

摘要

A new kind of polymer as slow-release fertilizer containing nitrogen, phosphorus and potassium (PSRNPK) was synthesized and the structure of the fertilizer was characterized by the FTIR spectrum. The N, P and K contents of the fertilizer are 21.4 wt%, 10.0 wt% (shown by P2O5), and 6.5 wt% (shown by K2O), respectively. Because the nutrient release of polymer as slow-release fertilizer depended on the speed of degradation, this study evaluated the release patterns of N, P, and K from PSRNPK at pH values of 4.0, 5.6, 7.0, 8.4, and 10.0. Additionally, the effect of temperature on the nutrients release behaviors was investigated. The results showed that the PSRNPK possessed an excellent slow release property, and the releases of N, P are pH dependent. N was released rapidly in both acid and base systems, respectively, while the release of P was suppressed by acid, and the K release speed was not influenced by the pH. Hydrolysis reaction mechanism was proposed based on the controlled experiments.