Assessment of Water Stress in Mung Bean (Vigna radiata (L.) Wilczek) by Infrared Thermometry and Its Relationship with Irrigation Scheduling and Yield Performance

OpenAlex İngilizce

This study was conducted during the 2018 growing season in Kahramanmaraş Province, Türkiye, to determine the response of mung bean (Vigna radiata (L.) Wilczek) to water stress under different irrigation strategies and seed densities using a drip irrigation system. Along with mung bean yield (Y), the potential use of Crop Water Stress Index (CWSI) in irrigation scheduling was also investigated. Three different seed densities; D1 = 2 kg/da, D2 = 3 kg/da and D3 = 4 kg/da were tested in combination with four irrigation treatments: full irrigation (FI), deficit irrigations (DI50 and DI75), and partial root-zone drying (PRD50). The experimental design was a randomized complete block design with three replications arranged in split plots. During the experimental period, canopy temperature measurements were taken for all treatments using an infrared thermometer, and CWSI values were calculated based on canopy–air temperature differences (Tc–Ta) and vapor pressure deficit (VPD). Hourly measurements throughout the day were used to establish the upper (UL) and lower (LL) baselines, with VPD values ranging from 1.67 to 3.30 kPa. The LL equation was determined as:(Tc−Ta)LL= −3.9283×VPD+2.1424; R2=0.87. CWSI values obtained for the tested treatments ranged between 0.00 and 0.77. The highest pre-irrigation CWSI value (0.30) observed in the FI-D3 treatment where the lowest CWSI values were subsequently recorded can be used as a threshold to initiate irrigation. A linear negative relationship was found between Y and CWSI, expressed by the equation:Y= −393.95×CWSI+863.22; R2=0.75. The results demonstrated that irrigation scheduling for mung bean can be effectively developed based on CWSI values.