Abstract:
This study was carried out to determine the relationship between the canopy-air temperature differential and
vapor pressure deficit (VPD), which can be used to quantify the crop water stress index (CWSI) under fully
irrigated ( 100 %) and maximum water stress (0 %) conditions of furrow irrigated corn. The effects of five
different irrigation levels (100, 70, 50, 30 and 0 % replenishment of soil water depleted from the 0.90 m soil
profile depth) on corn yields and the resulting CWSI were investigated. The highest yield and total water use
were obtained under fully irrigated corn plots (100 % replenishment of soil water depleted). The trends in CWSI
values were consistent with the soil water content induced by deficit irrigation. CWSI increased with increased
soil water deficit. An average CWSI of 0.22 before irrigation time provided the highest grain corn yield. The
yield was directly correlated with seasonal mean CWSI values and a second order polynomial equation “Y =
59258CWSI2 -72051CWSI +24060” can be used to predict the grain yield of corn as a second crop under the
semiarid climate.
