Irrigation water was supplied from a well using a pump. The water was classified as C1S1 with a sodium risk and a low electrical conductance (USSL, 1954). The 16 mm diameter lateral pipes carrying 2 L h−1water had inline drippers with 33 cm spacing. Soil water contents water contents were measured by the gravimetric method from the soil samples taken from soil depths with 30 cm increments in each plot at planting, before irrigations, and at the final harvesting date.
Experimental plots were irrigated by a sprinkler irrigation system at the beginning for a uniform plant establishment. Irrigation was carried out two times during this stage. After the emergence of maize seedlings, irrigations were performed by drip irrigation to irrigate a soil profile of 0–90 cm to field capacity. Subsequent irrigations were applied according to the prescribed irrigation rates with 7 day intervals. In present study, irrigation treatments were arranged according to five different deficit rates (Kn) of available soil water as follows