Advancing Nutrient Management in Agriculture: Rice Straw to Nitrogen, Phosphorus and Potassium-Containing Hydrogel as Slow-Release Fertilizer

Rice (Oryza sativa) straw management is challenging due to its large volume and environmental and health risks associated with traditional disposal methods. Sustainable practices like composting, bioenergy production, biochar, and other industrial applications can address these issues while providing economic advantages. This study introduces a method for converting Rice straw into a slow-release hydrogel containing nitrogen, phosphorus, and potassium (NPK) fertilizers. The process involves a series of acid-base pretreatment to enhance Rice straw reactivity, followed by graft copolymerization with acrylamide (AM) and N,N'-methylenebisacrylamide (MBA) to form a three-dimensional network that retains water and plant nutrients. The application of ammonium persulfate-ferrous sulfate (APS-FS) redox initiator system reduces the gelation time (