Determination of crop water stress index (CWSI) of second crop corn in a semiarid climate

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.