Effects of Zinc and Boron on Physiological Responses, Seed Quality, and Productivity of Peanut Grown in a Corn–Peanut Intercropping System under Moderate Deficit Irrigation

To evaluate whether foliar zinc (Zn) and boron (B) application can improve the physiological performance, nutrient status, seed quality, and productivity of peanut grown under moderate deficit irrigation in monocropping and peanut–corn intercropping systems. Field experiments were conducted during two consecutive growing seasons under hyper-arid conditions in Egypt. Peanut was grown as a monocrop or intercropped with corn under moderate deficit irrigation using alternate partial root-zone drip irrigation. Four foliar treatments were evaluated: deionized water (control), B (10 mg L−1), Zn (325 mg L−1), and Zn + B. Physiological traits, oxidative stress indicators, nutrient concentrations, seed quality, and yield were assessed. Intercropping increased oxidative stress indicators and antioxidant enzyme activities while reducing chlorophyll content, relative water content, carbohydrate reserves, mineral nutrient concentrations, seed quality, and yield compared with monocropping. Relative to the untreated intercropping control, Zn + B application increased chlorophyll content by 55.1