Authors: Osman YILDIRIM, Süleyman KODAL, Fatih SELENAY, Y. Ersoy YILDIRIM, Ahmet ÖZTÜRK
Abstract: This study was planned to determine the effects of both adequate and limited soil water supplies on grain yields of corn (Zea mays L.) during total and individual growth periods. Soil water deficits during certain growth periods were created by nonirrigation. The experiments were conducted at the Experimental Station of the Agricultural Faculty of the University of Ankara, in 1991 and 1992. The highest and the lowest grain yields were 10.85 t/ha from the plots with full irrigation and 3.47 t/ha from those without irrigation during the total growing period, respectively. Witholding irrigation during the ripening period did not affect the grain yield significantly. The greatest sensitivity to soil water deficit was at the flowering stage. Relative grain yield reductions were found to be 27.9%, 25.2%, 21.2%, 57%, 27.9%, 50.8%, and 68% when irrigation water was not applied during the vegetative, flowering, yield formation, vegetative and flowering, vegetative and yield formation, flowering and yield formation, and total growing periods, respectively. The yield response factor, ky, was found to be 0.97 for the total growing period, 0.78 for the flowering, and 0.47 for the vegetative and yield formation periods. According to these results, it was concluded than corn was rather sensitive to soil water deficits and should be irrigated throughout the total growing season with the exception of the ripening period to obtain high grain yields.