Improving Growth, Physiological Attributes and Yield of Mungbean (Vigna radiata L.) Through Optimization of Irrigation Regimes in Arid Regions

Abstract

Mungbean (Vigna radiata L.) growth and development are critically reduced by water deficit, necessitating optimized irrigation scheduling to achieve maximum economic yield. A field study was conducted over two consecutive growing seasons (2018 and 2019) at the Agronomic Research Station, Karor-Layyah, within an arid climatic zone to evaluate different irrigation regimes to optimize mungbean yield. The experiment was arranged in a randomized complete block design (RCBD) with four replications to evaluate eight irrigation regimes viz. I₀: Control (no irrigation), I₁: One irrigation at 35 Days After Sowing (DAS), I₂: One irrigation at 45 DAS, I₃: One irrigation at 55 DAS, I₄: Two irrigations at 35 and 45 DAS, I₅: Two irrigations at 35 and 55 DAS, I₆: Two irrigations at 45 and 55 DAS, I₇: Three irrigations at 35, 45, and 55 DAS. The results of the study revealed that the application of three irrigations at 35,45 & 55 Days of Sowing (DAS) resulted in the highest recorded values for key physiological indices, including leaf area index (LAI), crop growth rate (CGR), and total dry matter (TDM) accumulation. Yield and yield attributes were also maximized under the same treatment. Moreover, relative water content (RWC) and chlorophyll concentration were also superior in plots receiving three irrigations, timed specifically at 35,45 & 55 DAS, compared to fewer or no irrigation treatments. A remarkable exception was observed in seed protein content, which was significantly greater in the non-irrigated control treatment compared to all irrigated plots. However, this treatment also resulted in the lowest water use efficiency (WUE), recorded at 2.02 and 1.87 kg ha⁻¹ mm⁻¹ for the 2018 and 2019 seasons, respectively. In contrast, the three-irrigation regime (35,45 & 55 DAS) demonstrated the highest Water Use Efficiency (3.55 and 3.52 kg ha⁻¹ mm⁻¹), establishing it as the most effective strategy for enhancing yield and optimizing water productivity in mungbean cultivation under arid conditions.