Preparation and properties of macromelecular slow-release fertilizer containing nitrogen, phosphorus and potassium

A new kind of macromelecular slow-release fertilizer containing nitrogen, phosphorus and potassium (MSF) was prepared. The structures of the fertilizer were characterized by the FTIR spectrum and the gel permeation chromatography, which shows the uron rings structure and the average molecular weight of 13,500. And the N, P and K contents of the fertilizer are 24.2 wt%, 20.2 wt% (showed by P₂O₅) and 13.5 wt%( shown by K₂O), respectively by an element analysis experiment. The slow-release properties of the fertilizer in water and soil were further investigated, which shows the release of 39.5%, 91.8% and 98.9% for 30 days in soil corresponding to the N, P and K elements, respectively. The result is believed to come from the decomposition of the macromolecular fertilizer. Moreover, the effect of macromolecular fertilizer on the soil and water is environmentally friendly, which is expected to apply in modern agriculture.