Biochar-enriched hydrogels from grapevine pruning waste improve soil water retention and drought tolerance in Vitis vinifera L.

Water scarcity is a critical global issue requiring sustainable water management in agriculture. This study investigated hydrogels incorporating biochar derived from grapevine pruning waste and their effects on grapevine growth and antioxidant responses under two drought stress conditions. Plants were grown in pots containing raw hydrogels and hydrogels enriched with different concentrations of biochar, and exposed to two different drought levels. Scanning electron microscopy showed structural differences between raw and biochar-enriched hydrogels. Biochar-enriched hydrogels reduced water evaporation, indicating improved water-retention performance of the hydrogel system. Antioxidant enzyme activities (SOD, CAT) and lipid peroxidation (MDA) revealed that biochar content and hydrogel/peat ratios significantly influenced plant drought tolerance. Specific hydrogel-biochar combinations promoted plant growth and chlorophyll retention and modulated antioxidant responses under water-scarcity conditions, whereas the effects were not consistently associated with increasing biochar concentration. Overall, incorporating biochar into hydrogel systems is an effective strategy to improve water retention and mitigate drought stress, highlighting its potential as a sustainable soil conditioner to enhance crop resilience under water-limited conditions.