Calibration of Aydin-Oiger model for estimating evaporation from salinated soil under saline water conjunction irrigation strategy in an arid and semiarid region

Measuring soil evaporation is a difficult task and this can only be estimated either by usingempirical methods or by water balance calculation from a lysimeter. An adjustment of soilevaporation estimation is required since farm condition is different from the standard condition set by FAO (56). In field conditions, the evaporation is decreased by soil salinity. The main objective of this study was to calibrate Aydin-Oiger model for a saline soil under three schemes of saline water irrigation in an arid and semi-arid region. Three conjunction strategy of fresh (1 dS m-1) and saline water (14 dS m-1) (blending, one-alternate and half-alternate) in three replications were applied in a completely randomized design in nine lysimeters. Soil samples were taken in 11 dates and 11 data series were collected. Soil evaporation was calculated for the internal between the two consequent samplings. Eight series of data were used for calibration of a new model and the other three were used for validation of the calibrated model. ANOVA, EF and CRM indexes were used for determination of significant levels of the calibrated model and its evaluation. The results indicate that the calibrated model predicates soil evaporation better than the original Aydin-Oiger model.