Analysis of Spatiotemporal Features of Cassava Evapotranspiration in Benin Using Integrated FAO-56 Method and Terra/MODIS Data

Abstract

This study analyzed the temporal and spatial features of cassava evapotranspiration from 1985 to 2015 in Benin using linear regression, Mann-Kendall trend test, Sen’s slope estimator, and interpolation. The study used basic meteorological data from the Met office of Benin and the Terra/MODIS vegetation index. The estimated crop coefficients (Kc) from FAO and NDVI have shown a strong and positive linear relationship with a correlation coefficient of r = 0.968, while NDVI-Kc presented values slightly lower than FAO-Kc. The rates of crop evapotranspiration (ETc) varied from 1.23 to 7.63 mm/day and 2.92 mm/day on average. At the local level, there were significant upward trends in the seasonal ETc for stations located in the bimodal rainfall pattern area (Cotonou, Bohicon, and Save) and non-significant for stations in the unimodal rainfall pattern area (Kandi, Parakou, and Natitingou). At the country level, both methods revealed a non-significant positive trend in cassava evapotranspiration in the study area while showing a strong and positive linear relationship in variations throughout the growing season, r = 0.956. Cassava’s growth in Benin may encounter in the future the risk of water deficit.