Synthesis and Characterization of Sodium Carboxymethyl Cellulose/Sodium Alginate/Hydroxypropyl Cellulose Hydrogel for Agricultural Water Storage and Controlled Nutrient Release

Physically crosslinked superabsorbent hydrogels based on NaCMC, HPC, and NaAlg were developed to address the effects of water shortage to crop farming and to regulate fertilizer usage. An optimized synthesis was performed using ten different blends. The blend with a NaCMC/HPC/NaAlg ratio of 0.29/0.42/0.29 was found to exhibit the most favorable results, accommodating 1585% moisture and 8.38% fertilizer on a dry basis. Scanning electron microscope images of this blend manifested microporous structures, responsible for its superabsorbent properties. It was found out that applying the hydrogel at 5% loading to silt soil decreases fertilizer runoff by 28% and increases field capacity to 55%. Moreover, phytotoxicity studies showed that the optimum hydrogel blend exhibits no phytotoxic properties to pechay ( Brassica rapa subsp. chinensis ), lettuce eton ( Lactuca sativa ), and spinach ( Spinacia olera cea ), proving its applicability to agriculture.