Selecting models for the estimation of reference evapotranspiration for irrigation scheduling purposes

• Published in: PloS one Vol. 16; no. 1; p. e0245270
• Main Authors: Ferreira, Lucas Borges, da Cunha, Fernando França, Zanetti, Sidney Sara
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 11-01-2021; Public Library of Science (PLoS)
• Subjects: Agricultural engineering; Agricultural research; Biology and Life Sciences; Crop evapotranspiration; Earth Sciences; Effective precipitation; Empirical equations; Evapotranspiration; Evapotranspiration estimates; Field capacity; Humidity; Irrigation; Irrigation scheduling; Mathematical models; Measurement; Methods; Moisture content; People and places; Physical Sciences; Rain; Rainfall; Rainfall distribution; Research and Analysis Methods; Scheduling; Soil moisture; Soil water; Water content; Brazil
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0245270

Alternative models for the estimation of reference evapotranspiration (ETo) are typically assessed using traditional error metrics, such as root mean square error (RMSE), which may not be sufficient to select the best model for irrigation scheduling purposes. Thus, this study analyzes the performance of the original and calibrated Hargreaves-Samani (HS), Romanenko (ROM) and Jensen-Haise (JH) equations, initially assessed using traditional error metrics, for use in irrigation scheduling, considering the simulation of different irrigation intervals/time scales. Irrigation scheduling was simulated using meteorological data collected in Viçosa-MG and Mocambinho-MG, Brazil. The Penman-Monteith FAO-56 equation was used as benchmark. In general, the original equations did not perform well to estimate ETo, except the ROM and HS equations used at Viçosa and Mocambinho, respectively. Calibration and the increase in the time scale provided performance gains. When applied in irrigation scheduling, the calibrated HS and JH equations showed the best performances. Even with greater errors in estimating ETo, the calibrated HS equation performed similarly or better than the calibrated JH equation, as it had errors with greater potential to be canceled during the soil water balance. Finally, in addition to using error metrics, the performance of the models throughout the year should be considered in their assessment. Furthermore, simulating the application of ETo models in irrigation scheduling can provide valuable information for choosing the most suitable model.