Determinação do coeficiente de tanque classe “A” e análise de métodos diferentes ao Penman-Monteith-FAO para a estimativa da evapotranspiração de referência na região de Rivas - Nicarágua

Abstract

This study addresses the challenges inherent in estimating crop evapotranspiration (ETc) to improve irrigation management practices in the Rivas region, Nicaragua. The ETc is crucial in determining the proper amount of water to apply to crops, and is often calculated from the reference evapotranspiration (ET0), which is adjusted by the crop coefficient to result the ETc. The main objective of this research was to evaluate the effectiveness of the Class A pan method, proposed by Doorenbos & Pruitt, in addition to the methods of Thornthwaite, Camargo and Hargreaves and Samani, in estimating the ET0 in the region of Rivas. Daily weather data collected between 1995 and 2021 from a meteorological station at the Companhia Açucareira do Sul were the database analyzed. The Penman Monteith-FAO56 method was adopted as a reference for comparison. The results revealed that none of the investigated methods had a satisfactory performance in the precise estimation of the ET0 in Rivas. Their performance varied predominantly between terrible and unsatisfactory levels, as assessed by multiple criteria, including determination coefficient, linear regression parameters, estimation standard error, Willmott concordance index, Pearson correlation coefficient, and reliability coefficient. Therefore, the research concludes that the evaluated methods are not adequate to accurately estimate ET0 in this specific region. Given these results, it is suggested the need to investigate other estimation approaches that adapt more effectively to local climatic characteristics, to improve the agricultural productivity and optimize the use of water resources in the region.