IMPACT OF POTASH DELIVERY METHODS ON SOIL PLANT WATER RELATIONS AND YIELD TRAITS OF MUNGBEAN UNDER MOISTURE STRESS

Background: Water scarcity is a critical barrier to sustainable mungbean (Vigna radiata L.) production in arid and semi-arid regions. Limited soil moisture significantly reduces plant growth, pod set, seed filling, and yield. Potassium (K) is a vital nutrient that enhances drought tolerance by improving osmotic adjustment, photosynthesis, and assimilate translocation. However, comparative evaluation of different application methods of potassium in mungbean under water-deficit conditions has received limited attention. Objective: This study aimed to investigate the influence of different potassium application methods on growth, physiological traits, and yield of mungbean grown under water-limited conditions in southern Punjab, Pakistan. Methods: A field experiment was conducted during the spring season of 2017 at the Research Farm of Bahauddin Zakariya University, Multan. The trial was laid out in a Randomized Complete Block Design with three replications. Four treatments were applied: T₀ (control, no K), T₁ (seed coating with potassium), T₂ (foliar spray at 30 days after sowing), and T₃ (broadcasting before land preparation). The mungbean cultivar NM-92 was sown manually at 20 kg ha⁻¹ with a 30 cm row spacing. Urea and triple super phosphate were applied uniformly, and potassium was supplied as sulfate of potash according to the treatment protocols. Standard agronomic practices were followed, and data on plant height, fresh and dry weights, leaves per plant, pod and seed traits, 1000-seed weight, biological yield, and grain yield were recorded and statistically analyzed. Results: Significant variations were observed among treatments. Seed coating (T₁) achieved maximum plant height (58.67 cm), fresh weight (53.33 g), dry weight (21.67 g), and leaf number (102). It also produced the highest pod number (142), seeds per pod (10.33), seed weight per pod (188.21 g), 1000-seed weight (288.11 g), biological yield (38.11 t ha⁻¹), and grain yield (8.11 t ha⁻¹). Foliar application (T₂) followed, with plant height of 56.33 cm, pod number of 133.67, 1000-seed weight of 262.62 g, biological yield of 26.62 t ha⁻¹, and grain yield of 6.62 t ha⁻¹. Broadcasting (T₃) showed moderate improvements, while the control (T₀) consistently produced the lowest values. Conclusion: Seed coating with potassium was identified as the most effective method for enhancing growth and yield of mungbean under drought stress, offering a practical nutrient management strategy to improve productivity in water-deficit environments.