Determination of Crop Water Stress Index for Irrigation Scheduling of Bean (Phaseolus vulgaris L.)

Authors: YEŞİM ERDEM, SEZEN ŞEHİRALİ, TOLGA ERDEM, DİNÇER KENAR

Abstract: This study was conducted to determine the relationship between the canopy-air temperature differential and the vapor pressure deficit (VPD), which can be used to quantify the crop water stress index (CWSI) under fully irrigated (100%) and maximum water stress (0%) conditions of trickle irrigated bean. The effects of 5 irrigation levels (100%, 75%, 50%, 25%, and 0% replenishment of soil water depleted when 50% of available soil moisture was consumed in the 0.60 m soil profile depth of fully irrigated treatment) on seed yields and resulting CWSIs calculated using the empirical approach were also investigated. The highest yield and water use were obtained with fully watered plants (100% replenishment of soil water depleted). The trends in CWSI values were consistent with the soil water content induced by deficit irrigation. CWSI increased with increased soil water deficit. The yield was directly correlated with seasonal mean CWSI values and the linear equation Y = 2.731 - 2.034 CWSI can be used for yield prediction. The CWSI value was useful for evaluating crop water stress in bean and should be useful for timing irrigation and predicting yield.

Keywords: Canopy temperature, vapor pressure deficit (VPD), irrigation, evapotranspiration, bean

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