New approach to estimate the additional water requirements in sprinkler irrigation: a predictive model

Abstract

A regression model was developed from ET rates measured over sprinkler irrigated cotton by an ECV/energy balance technique. Rates from several trials were nondimensionalised and averaged to remove variation caused by cloud, time of day and experimental factors. Prior to irrigation the nondimensional ET followed a linear relationship. After commencing irrigation the rate of ET quickly jumped to a significantly higher value and stabilized to follow a linear relationship until conclusion of the irrigation. The ET decreased over the post irrigation drying period, following an exponential decay until again reaching a steady value. The model allows estimation of the additional water requirements in sprinkler irrigation to be estimated for other times and locations.