Thornthwaite and mather soil water balance model adapted for estimation of real evapotranspiration of the pasture
| Autor: | Gustavo Bastos Lyra, Marcel Carvalho Abreu, Suelen da Costa Faria Martins, João Paulo Francisco, Guilherme Bastos Lyra, Leonardo Duarte Batista da Silva, Fabiana da Costa Barros |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Hydrology
geography Irrigation geography.geographical_feature_category Automatic weather station Water extraction General Medicine Bowen ratio Agrometeorological Modeling Single Crop Coefficient Water Consumption Pasture Water balance Bowen ratio Altitude Single Crop Coefficient Evapotranspiration Environmental science Agrometeorological Modeling |
| Zdroj: | Engineering in Agriculture; Vol. 29 (2021): Publicação Contínua; 146-156 Revista Engenharia na Agricultura-REVENG; v. 29 (2021): Publicação Contínua; 146-156 Engenharia na Agricultura Universidade Federal de Viçosa (UFV) instacron:UFV |
| ISSN: | 2175-6813 1414-3984 |
| DOI: | 10.13083/reveng.v29i1.11703 |
| Popis: | Knowing the real pastures demand is essential for a more rational use of irrigation. The present work deals with the performance of the Thornthwaite and Mather water balance method (ThM) adapted to estimate the daily actual evapotranspiration (ETa) of a pasture in relation to the Bowen ratio - energy balance method (BREB). The experiment was carried out from July 2018 to June 2019 in Cachoeiras de Macacu, RJ (22º 27 'S; 42º 45' W and 30 m altitude). Micrometeorological and meteorological measurements were conducted in a micrometeorological mast installed in the pasture and also in an automatic weather station. The ThM model was evaluated by simple linear regression between ETa BERB and the estimates from ThM, by its determination coefficient (r²) and the modified Willmott agreement index (dm). The ThM model underestimated (between 11 and 16%) ETa for all seasons, with the exception of spring, which overestimated 1%. The highest precision and accuracy of the estimates were observed in autumn (r² = 0.84 and dm = 0.68) and spring (r² = 0.83 and dm = 0.82). In summer (r² = 0.56 and dm = 0.73) and winter (r² = 0.43 and dm = 0.66), the lower performance was due to the model inability to represent water extraction from the soil in absence periods of rainfall. Determining the real water requirement for pastures is essential for the rational use of irrigation. The aim of this work was to assess the crop coefficient and performance of the Thornthwaite and Mather soil water balance (ThM) adapted to estimate the daily actual evapotranspiration (ETa) of a pasture in relation to the Bowen ratio - energy balance method (BREB). The experiment was carried out from July 2018 to June 2019 in Cachoeiras de Macacu, Rio de Janeiro State (RJ) (22º 27’S; 42º 45’W and 30 m altitude). Micrometeorological and meteorological measurements were conducted in a micrometeorological tower installed in the pasture and also in an automatic weather station, located 1 km from the pasture area. The ThM model was evaluated using linear regression between ETa determinate from BREB and the estimates from ThM using its coefficient of determination (R²) and the modified Willmott agreement index (dm). The ThM model underestimated (between 11 and 16%) the ETa for all seasons, except for spring, which overestimated by 1%. The highest precision and accuracy of the estimates were observed in autumn (R² = 0.84 and dm = 0.68) and spring (R² = 0.83 and dm = 0.82). In summer (R² = 0.56 and dm = 0.73) and winter (R² = 0.43 and dm = 0.66), the lower performance was caused by the inability of the model to represent water extraction from the soil in dry periods. |
| Databáze: | OpenAIRE |
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