Effects of Ethanol and Zinc Sulfate Foliar Application on Yield and Drought Tolerance of Peanut (Arachis hypogaea L.)

Water scarcity is a major constraint in peanut production, necessitating cost-effective strategies to mitigate yield losses. This two-year study (2018–2019) is the first to investigate the synergistic effects of foliar-applied ethanol (0, 3, 6% v/v) and zinc sulfate (0, 1500, 3000 ppm) under three irrigation regimes [well-watered after 50 mm evaporation (IR50), mild drought stress after 100 mm evaporation (IR100), and severe drought stress after 150 mm evaporation (IR150)] using a split-factorial experiment based on randomized complete block design. The combined application of 3% ethanol and 3000 ppm zinc sulfate was the most effective treatment, reducing severe drought damage by 40–50%. This synergy effectively maintained pod, kernel, and oil yields under severe stress at 2587.71, 1944.41, and 975.51 kg ha⁻¹, respectively, while also maximizing yields under well-watered conditions. The physiological basis for this resilience was a fortified antioxidant system, evidenced by a 29% increase in catalase activity and a 15–30% reduction in malondialdehyde content, indicating lower oxidative stress. Crucially, the marginal yield gain from 3000 ppm zinc over 1500 ppm was negligible (~ 1%). Therefore, we recommend the foliar co-application of 3% ethanol with 1500 ppm zinc sulfate as a highly efficient and economically viable strategy to bolster drought tolerance, reduce irrigation dependency, and secure peanut oil production in water-limited environments.