Improving Herbaceous Cotton Performance Under Drought Scenario Through Sustainable Hydrogel Polymers

Abstract Water scarcity is one of the main challenges for agricultural production in semiarid regions, compromising the development of crops such as upland cotton ( Gossypium hirsutum L.). Using starch-based biodegradable hydrogels emerge as a sustainable alternative to synthetic polymers to improve soil water retention. Our working hypothesis was that biodegradable cassava starch-based hydrogels alleviate drought damage in cotton plants associated with improved physiological coordination. Two parallels trials were conducted in greenhouse and field, in a randomized complete block design, 2 × 2 factorial scheme, combining two water regimes [well-irrigated at 90% field capacity (FC), and drought at 50% FC] and two hydrogel levels (0 and 1.0 g per plant). Drought modulated the physiological responses and significantly decreased the biometric data and biomass accumulation in both environments. The data revealed that the agronomic effectiveness of cassava starch-based hydrogel is strongly dependent on the environment. In the greenhouse, hydrogel partially mitigated drought-induced reductions in stomatal conductance and instantaneous water use efficiency without result in biomass improvement. In contrast, under field conditions, hydrogel-treated stressed plants preserved the photosynthetic pigments, a response associated with enhanced water use efficiency and shoot dry mass, resulting in an increased relative drought tolerance. In conclusion, hydrogel polymers alleviate drought damages on cotton performance under field conditions, highlighting potential of biopolymer incorporation into sustainable water management practices.