Carboxymethyl Cellulose‐Based Composite Hydrogels for Sustainable Agriculture Under Drought Stress

ABSTRACT This study investigates the synthesis and characterization of a DAP‐loaded composite hydrogel comprising carboxymethyl cellulose‐g‐poly(acrylic acid‐acrylamide)/diatomite (CMC‐g‐P(AA‐AAm)/diatomite/DAP) using chemical crosslinking. The incorporation of diatomite enhanced the equilibrium water absorbency of the hydrogel by 54.48% in distilled water and 34.02% in tap water. The hydrogel demonstrated excellent reswelling capacity, maintaining 105.8 g/g and 36.13 g/g in distilled and tap water, respectively, after 10 cycles. Soil treated with the hydrogel retained the highest water at a 0.3% concentration, showing a 291% increase at 35°C compared to the control. Composite hydrogel treatments improved soil physiochemical properties, including bulk density, porosity, organic carbon, water‐holding capacity, and microbial counts while reducing soil pH. The hydrogel facilitated a controlled release of nitrogen and phosphorus, following Fickian diffusion. Enhanced germination rates and improved mustard plant growth under drought conditions were observed, indicating the potential of hydrogel in sustainable agriculture. Further research and field trials are required to evaluate its performance under diverse soil and climate conditions, paving the way for its widespread adoption.