where ETc is the crop water requirements (mm day−1) and Kc is
the crop coefficient.
The duration of the different crop growth stages were 25, 40,
45, and 30 days for initial, crop development, mid-season and late
season stages, respectively and the crop coefficients (Kc) of initial,
mid and end stages were 0.70, 1.20 and 0.35, respectively, according
to Allen et al. (1998).
The amount of irrigation water applied to each treatment during
the irrigation regime was determined by using Eq. (3):