Authors: Semih Metin SEZEN, Attila YAZAR
Abstract: Water-yield relations for winter wheat differentially irrigated with a line source sprinkler system under Cukurova conditions are determined. Different irrigation stress levels were created by using a line source sprinkler system and yields were found to be significantly different among the treatments studied. The highest yield with 753.2 kg/da was obtained from the non-stressed treatmet (I1) (adjacent to the lateral) during the growing periods. The lowest yield with 587.3 kg/da was obtained from the non-irrigated (dry) treatment (I5). Seasonal evapotranspiration was determined to be 518.8 mm with the highest yielding treatment (I1), and the average daily maximum water consumption occured in April with 4.5 mm per day. A significant linear relationship between the seasonal evapotranspiration and the grain yield was obtined. The yield response factor (ky) was found to be 1.01 in the relationship between the relative evapotranspiration deficit and the relative yield reduction for total growing period. The main reason for the yield reduction under water stress may be attributed to incomplete fill of the grains before maturation. This condition is particularly obvious in the non-irrigated treatment.