Determination of transpiration rate using stable isotope mixing model in different irrigation regimes for winter wheat

The main goal of this research was to partition evapotranspiration (et) into evaporation (e) and transpiration (t) components for determining transpiration rate of wheat using by oxygen isotope discrimination. field experiment was conducted between the year 2009 and 2011 under rainfed (so) and full irrigation (s1) conditions on 5 hectares plots in ankara-murted basin. soil-water-plant samples was taken during growing period for isotopic (18o/16o) analyses. keeling plot methods were used to determine transpiration (ft %) and evaporation (fe %) rate from atmospheric vapor (δet), soil (δe) and plant stem (δt) isotopic δ18o content. according to research results; two years average of t/et was found for s0 treatment 50.80, 69.09 and 79.87% and for s1 treatment 53.24, 75.82 and 95.13% at 1-15-29 may respectively. this study has indicated that stable isotopes can be used to protect limited water resources and to promote sustainable use.