WinSRFR model validation in border irrigation in a soil in southern Uruguay

Abstract

In Uruguay, the irrigation boom driven by rice cultivation between the 1970s and 2000s and the subsequent reduction of the rice area led to the underuse of impounded water. Surface irrigation of sown pastures would seem to be a good alternative to solve this problem. But, although surface irrigation has advantages, its applicability is limited by the need for precise systematization and it is not suitable for light soils, with a loamy to sandy loam texture, with a slope. This study seeks to adjust the border irrigation technology in southern Uruguay and validate the WinSRFR model in border irrigation with pastures. Nine borders were used with slopes of 2.5% to 3%, widths of 5.5 to 6.3 m and lengths of 50 to 65 m. Previously optimized flow rates were used and soil moisture was monitored with an FDR probe. Operational analysis with WinSRFR determined the necessary irrigation time. Performance parameters were evaluated: application efficiency, distribution uniformity, storage efficiency, percolation losses and runoff at the foot. The results reveal a high correlation between the model-simulated data and the observed data. Validation was carried out using 11 events of the 21 evaluated. The sensitivity analysis of the model showed a high impact on slopes of less than 1% and had no relevant effects above 3%. Variations in the roughness coefficient (n) have limited effect. Furthermore, the infiltration family influences the performance parameters.

Keywords

• application efficiency
• distribution uniformity
• simulation models
• surface irrigation