In this study, effects of different applications of irrigation on yield of sunflower (Helianthus annuus L.) and usability of plant-based measurement techniques in irrigation applications were investigated. As a result of the study, the evapotranspiration values measured in the experimental subjects during the plant growing season changed, depending on the amount of irrigation water applied, between 375.2 and 655.0 mm in 2018 and between 278.2 and 801.3 mm in 2019. The seed yields obtained from treatments in both years changed depending on the amount of water entering the soil (precipitation + irrigation). Linear relationships were calculated between applied irrigation water, measured seasonal evapotranspiration and seed yields of sunflower. The IWUE (Irrigation Water Use Efficiency) and WUE (Water Use Efficiency) values were found to be high in the experimental treatments with less irrigation water. As a result of the study, it can be suggested that 25 and 50% of the evaporation values measured from class A pan evaporation is applied under limited water supply conditions. In the under-limited water conditions, the leaf area index value of 2.83-3.95 m2 m-2, leaf water potential value of -13 and -14 bar, chlorophyll content of 45-50, stomatal conductance value of 35-70 mmol m-2 s-1, photosynthesis rate value of 25-30 μmol CO2 m-2 s-1 and transpiration rate of 5-8 mmol H2O m-2 s-1 can be used for irrigation applications, especially in the flowering period of sunflower. It is important to determine the irrigation data required for sunflower in terms of protection of soil and water resources in conditions where irrigation practices are not very intensive and drip irrigation applications are new.

28.2.2023