Bentonite-enhanced sanxan: A pathway to slow-release, eco-friendly fertilizers

Hydrogel-based slow-release fertilizers, anchored in sanxan, offer a promising path towards sustainable agriculture, yet they face hurdles like elevated production costs and stability concerns. In this study, we aimed to boost the practicality and stability of sanxan fertilizers with a new granular slow-release formula. We evaluated the physical properties of sanxan compounded with bentonite, kaolin, and sodium humate as carrier granules, and optimized the formulation of the sanxan/bentonite composite and validated its effectiveness through crop experiments. The resulting sanxan/bentonite composite slow-release fertilizer (SB-SRF), fine-tuned at a sanxanto-bentonite ratio of 1:10, showcases improved physical properties, with a hardness of 14.90 kg and sphericity of 0.90. The formulation with 75% urea achieved a loading rate of 3.95 g/g and an encapsulation rate of 95.56%. Post-treatment at 90 degrees C led to a 175.62% increase in hardness and 63.52% in elasticity, enhancing structural integrity. Pot experiments confirmed that SB-SRF boosts corn biomass by 36.64% and chlorophyll content by 15.09%, with negligible effects on soil bacteria, thus exhibiting excellent soil compatibility. The innovative insights into the sanxan-bentonite interaction from this study provide a novel approach for developing costeffective, eco-friendly controlled-release fertilizers, propelling sustainable agricultural practices forward.