Yield Components and Crop Water Stress Index (CWSI) of Mung Bean Grown Under Deficit Irrigations

This study was conducted in 2018 growing season to determine the response of mung bean to water stress. Effects of different irrigation levels on mung bean yield and yield components and potential use of crop water stress index (CWSI) in mung bean irrigation scheduling were also investigated. Five different irrigation levels (I-100, I-75, I-50, I-25 and I-0) were applied through drip irrigation system. Amount of irrigation water supplied varied between 20-445 mm. Plant water consumption (ET) values varied between 125-521 mm. The highest yield (163 kg/da) was obtained from full-irrigation (I-100) and the lowest yield (39.7 kg/da) was obtained from rain-fed (I-0) treatment without irrigations. Plant heights varied between 58.6-21.2 cm, the first pod heights between 17.4-29.3 cm, number of branches per plant between 1.00-2.77 and number of pods per plant between 3.2-18.9. Water use efficiency (WUE) values varied between 0.31-0.50 kg/m(3) and irrigation water usage efficiency (IWUE) values varied between 0.37-0.77 kg/m(3). Crop water stress index (CWSI) values varied between 0.13-0.93. The lower limit (LL) equation was obtained as Tc-Ta = -2.9674 x VPD + 4.1341 (R-2 = 0.66) and the upper limit (UL) was identified as 9.7 degrees C. Highly significant (p < 0.01) correlations were seen between CWSI and yield. Based on present findings, I-75 was recommended under water deficit conditions. CWSI values of between 0.13-0.22 can be used to initiate irrigations for drip-irrigated mung bean.