The present investigations aim to decipher the beneficial role of hydrogen peroxide-supplemented irrigation in imparting drought tolerance and promotion plant growth and yield of potato plants grown under two different irrigation regimes. Hydrogen peroxide injection (oxygenation) was applied at 0, 300, and 600 ppm through subsurface irrigation regimes on potato performance grown in heavy clay soil. The results indicated that oxygenation of irrigation water boosted the plant′s vegetative growth and productivity, especially at 600 ppm hydrogen peroxide coupled with deficit irrigation. Root respiration, leaf biomass, chlorophyll content, and leaf osmotic status was observed to be improved in the presence of oxygenated irrigation. A similar trend was recorded on macro-elements (nitrogen, phosphorus, potassium and calcium content), proline, and soluble carbohydrates content of leaf along with catalase enzyme activity. Individual tuber weight, tuber number and tuber yield per plant and hectare recorded higher values as responding to oxygenated irrigation (300 and 600 ppm) of water within the optimum irrigation level. While the highest value of water use efficiency (WUE) was obtained by pairing deficit irrigation with 600 ppm oxygenated water. Thus, the present work provides new insights into the importance of oxygenated irrigation in obtaining optimum yield and field performance in potato plants subjected to deficit irrigation in clayey-loamy soils.

Purpose: Salicylic acid (SA) and benzoic acid (BA) are important phenolic regulators involved in plant growth and defense; however, their comparative roles in modulating growth and secondary metabolites production in leafy vegetables remain unclear. Therefore, this study aimed to investigate the influence of exogenous SA and BA on growth, mineral composition, and bioactive compound accumulation in Swiss chard ( Beta vulgaris L. var. cicla ). Methods: Field experiments were conducted over two successive seasons of 2023/24 and 2024/25 to assess the influence of SA and BA on Swiss chard cv. Ruby Red. Plants were treated with SA and BA at 1, 2, and 3 mM, each alongside an untreated control. Treatments were arranged in a randomized complete block design with three replicates. Beside the agronomic attributes, photosynthetic pigments, total phenols, total flavonoids, total antioxidant activity, total indoles, anthocyanin, nitrate, and mineral content were assayed. Results: Both SA and BA significantly improved growth parameters, mineral content, and secondary metabolites accumulation compared to the control. SA at 1 mM or BA 1 mM were the most effective treatments, showing the highest significant values of vegetative parameters, photosynthetic pigments, total phenolics, total flavonoids, total antioxidant activity, total indoles, anthocyanin, and mineral content. Further, BA 1 mM was the potent treatment for lowering leaf nitrate content, showing the lowest nitrate content, which was significantly lower than SA at 2 and 3 mM. Correlation analysis revealed strong positive relationships between growth parameters and secondary metabolites. Conclusion: BA behaves influence similar to SA for enhancing leaves yield with higher efficacy in reducing nitrate content via enhancing the efficiency of photosynthetic pigments and regulating various secondary metabolites. Herein, BA at low concentration (1 mM) is a promising rate to be applied to obtain high yield with good quality.