Deficit irrigation effects on sweet corn (Zea mays saccharata Sturt) with drip irrigation system in a semi-arid region: I. Water-yield relationship

This study was conducted to determine appropriate irrigation frequencies and water-yield relationship for sweet corn irrigated by drip irrigation system in a semi-arid region. The research was carried out at the Agricultural Research Station of Harran University in Sanliurfa, Turkey, in 1998 and 1999. In the study, water was applied to sweet corn as 100, 90, 80 and 70% of evaporation from a Class A Pan corresponding to 2-, 4-, 6-and 8-day irrigation frequencies, respectively. Irrigation water applied to crops ranged between 610 and 876 mm in 1998, while 612–889 mm of water was applied in 1999. The highest values for total water use efficiency (TWUE) were found to be 1.38 and 1.24 kg m^-3 in the 4-day irrigation frequency in 1998 and 1999, respectively. The highest values for irrigation water use efficiency (IWUE) were determined to be 1.66 kg m^-3 in the 4-day irrigation frequency in 1998 and 1.59 kg m^-3 in the 6-day irrigation frequency in 1999. Crop response factor (ky) ranged from 0.76 to 1.22 in 1998 and from 0.96 to 1.29 in 1999. Fresh ear yield, based on the irrigation frequencies, was found to be statistically significant (**P<0.01) in both years. The highest fresh ear yields were 13.66 and 13.19 t ha-1 for the 2-day irrigation frequency in 1998 and 1999, respectively. The minimum fresh ear yields were found to be 8.55 and 7.29 t ha-1 with the 8-day irrigation frequency in 1998 and 1999, respectively. Yield was reduced with deficit irrigation in both years. The results of this research indicate that a 2-day irrigation frequency, with 100% ET water application by a drip system, will be optimal for sweet corn grown in semi-arid regions similar to that in Turkey where the work was conducted.