Effects of Humic Acid and Amino Acid Foliar Application on Biochemical Traits, and Grain Weight of Mung Bean (Vigna radiata L.) under Water Deficit Stress Conditions

Document Type : Research Paper

Authors

Department of Agrotechnology, Faculty of Agriculture, University of Tarbiat Modares, Tehran, Iran

Abstract

To evaluate the effects of different levels of amino acid foliar application and humic acid soil amendment under water deficit conditions on mung bean, a pot experiment was conducted in a semi-open greenhouse in Urmia, West Azerbaijan, during the 2022 growing season. The study was arranged as a three-factor factorial in a randomized complete block design with three replications. Experimental factors included three irrigation regimes (well-watered, mild stress, and severe stress), foliar application of a commercial amino acid product (Amino Rich) at six levels (no spray, distilled water, and 1, 2, 3, and 4 g L⁻¹), and humic acid at two levels (0.1 g per pot and no application). The highest plant height (26.6 cm) was recorded under well-watered conditions with 3 g L⁻¹ amino acid and humic acid, showing a 47% increase compared to the control. The largest leaf area (51.7 cm²) was obtained from 2 g L⁻¹ amino acid combined with humic acid under optimal irrigation, while the lowest (17.1 cm²) occurred with distilled water under severe stress. Photosynthetic pigment and anthocyanin concentrations increased with amino acid and humic acid treatments. The highest seed number per plant (26.2) was achieved with humic acid under well-watered conditions, representing a 40% increase over the control. The greatest seed yield (1883.3 mg plant⁻¹) was obtained from 2 g L⁻¹ amino acid plus humic acid under optimal irrigation. Overall, this combination was the most effective treatment in mitigating drought stress effects on mung bean.

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Articles in Press, Accepted Manuscript
Available Online from 04 June 2026
  • Receive Date: 18 November 2025
  • Revise Date: 15 January 2026
  • Accept Date: 17 January 2026
  • Publish Date: 04 June 2026