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. | Turk J Agric For 30 (2006) 195-202 © TÜB‹TAK Determination of Crop Water Stress Index for Irrigation Scheduling of Bean (Phaseolus vulgaris L.) Yeflim ERDEM1,*, Sezen fiEH‹RAL‹2, Tolga ERDEM1, Dinçer KENAR2 1 Faculty of Agriculture, Department of Farm Structures and Irrigation, University of Trakya, 59030 Tekirda¤ - TURKEY 2 Faculty of Agriculture, Department of Field Crops, University of Trakya, 59030 Tekirda¤ - TURKEY Received: 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 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 = – 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. Key Words: Canopy temperature, vapor pressure deficit (VPD), irrigation, evapotranspiration, bean Fasulyenin (Phaseolus vulgaris L.) Sulama Zaman› Planlamas›nda Bitki Su Stresi ‹ndeksinin De¤erlendirilmesi Özet: Bu çal›flma, damla sulama yöntemi ile sulanan fasulyenin, maksimum su stresi (%0) ve tam sulama koflullar›nda (%100), bitki su stresi indeks (CWSI) de¤erlerinin elde
