Inceptive Assessment of a New Olive Mill Waste–derived Biostimulant for Mitigating Water Stress in Pomegranate Trees

Water scarcity is a major constraint to the pomegranate (Punica granatum L.) cultivation. A need to find a new sustainable strategy to emphasize the tolerance of trees to water stress is necessary. In this context, the present study shows an initial evaluation of a novel biostimulant, prepared by a mix of phenolic extract (PE) and lignin nanoparticles (LNPs) extracted from olive mill solid waste (OMSW), applied on pomegranate trees submitted to deficit irrigation (ST) which compared to control (C) and deficit irrigation (S) treatments. Various parameters were evaluated. In treated leaves, the biostimulant has enhanced the content in total chlorophylls, decreased the malondialdehyde and starch, but the total phenolic and flavonoids content didn’t show any significant variation. With treatment (ST), the weight of fruits was ameliorated and the juice content was enriched by soluble solids, phenols, flavonoids and lycopene. In conclusion, this study opens the horizon of the validity use of bioactive compounds with a biostimulant action by recycling and valorizing bio-residues from olive oil chain production.