Abstract
In this study, effects of different amount of irrigation applications on water use, yield and yield parameters of sunflower plant in Thrace Region conditions were investigated. The six different irrigation water amounts with 7 days interval applied based on a ratio of Class A pan evaporation as 0, 25, 50, 75, 100 and 125% were created in the research. In the first year of the study, irrigation water was applied to all experimental subjects between 67.0 and 334.8 mm with 7 irrigation applications and 133.7 to 668.1 mm with 12 irrigation applications in the second year of the experiment. As a result of the research, 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 sunflower seed yields obtained from the experiment subjects ranged between 272.88 kg da-1 and 503.73 kg da-1 in the first year of the experiment and 222.49 kg da-1 to 518.61 kg da-1 in the second year of the experiment. In addition, as a result of statistical analyses, it was concluded that different irrigation applications do not affect vegetative growth and yield parameters. The seed yields obtained from treatments in both years changed depending on the amount of water entering the soil (precipitation + irrigation). As a result of the research, it can be suggested to apply 100% and 125% of the evaporation measured from the Class A pan in 7 days irrigation interval under conditions where the water resources are sufficient and the drip irrigation method is applied. On the other hand, considering the high IWUE and WUE values in conditions where the water supply is limited, it may be recommended to apply 25 and 50% of the evaporation measured from the Class A pan.