Zinc and amino acids improve the growth, physiological, and biochemical attributes of corn under different irrigation levels

The global challenge of food security is threatened by drought stress. Exogenous application of zinc and amino acids could alleviate the negative impacts of water shortage on the growth, physiological, and biochemical attributes of plants. Based on this hypothesis, a field study was conducted to assess the effects of chelated zinc applied through irrigation systems and foliar amino acids on the growth, physiological and biochemical attributes of corn, under three irrigation levels at the recommended irrigation level (100%), and at 75% and 50% of the recommended rate. The treatments were arranged in randomized complete block design in triplicate. Treatment effects on yield varied with intensity and duration of water stress. An irrigation level of 100% means the normal supply of recommended water. In results, the implementation of irrigation levels on corn led to varying impacts on yield, depending on the intensity and duration of the water stress. Plants responded by reallocating nutrient accumulation within their tissues, which played a crucial role in mitigating the negative effects of water stress. The application of zinc and amino acids individually showed positive effects on corn improvement, as these promoted antioxidant defense systems and enhanced corn yield. However, the combined application of foliar amino acids and soil-applied zinc, particularly under the 75% irrigation level, had a tremendous effect on various examined parameters. There was an increase in catalase by 65.9%, superoxide dismutase by 17.1%, and peroxidase by 15.1%, resulting in improved corn yield by 114.6% and decreased hydrogen peroxide contents by 74.2% compared to control. In conclusion, adopting 75% of the applied water and treating corn plants with a combination of zinc and amino acids resulted in the highest yield, nutrient accumulation, antioxidant enzymes, chlorophyll contents, relative water contents, and carbohydrate levels.