Many remote sensing‐based evapotranspiration (RSBET) algorithms have been proposed in the past decades and evaluated using flux tower data, mainly over North America and Europe. Model evaluation across South America has been done locally or using only a single algorithm at a time. Here, we provide the first evaluation of multiple RSBET models, at a daily scale, across a wide variety of biomes, climate zones, and land uses in South America. We used meteorological data from 25 flux towers to force four RSBET models: Priestley–Taylor Jet Propulsion Laboratory (PT‐JPL), Global Land Evaporation Amsterdam Model (GLEAM), Penman–Monteith Mu model (PM‐MOD), and Penman–Monteith Nagler model (PM‐VI). was predicted satisfactorily by all four models, with correlations consistently higher () for GLEAM and PT‐JPL, and PM‐MOD and PM‐VI presenting overall better responses in terms of percent bias (%). As for PM‐VI, this outcome is expected, given that the model requires calibration with local data. Model skill seems to be unrelated to land‐use but instead presented some dependency on biome and climate, with the models producing the best results for wet to moderately wet environments. Our findings show the suitability of individual models for a number of combinations of land cover types, biomes, and climates. At the same time, no model outperformed the others for all conditions, which emphasizes the need for adapting individual algorithms to take into account intrinsic characteristics of climates and ecosystems in South America.

The Caatinga dry forest encompasses 11% of the total continental territory of Brazil. Nevertheless, most research on the relationship between phenology and ecosystem productivity of Brazilian tropical forests is aimed at the Amazon basin. Thus, in this study we evaluated the seasonality of ecosystem productivity (gross primary production—GPP) in a preserved Caatinga environment in northeast Brazil. Analyses were carried out using eddy covariance measurements and satellite-derived data from sensor MODIS (MODerate Resolution Imaging Spectroradiometer, MOD17 and MOD13 products). In addition to GPP, we investigated water use efficiency (WUE) and meteorological and phenological aspects through remotely sensed vegetation indices (NDVI and EVI). We verified that ecosystem productivity is limited mainly by evapotranspiration, with maximum GPP values registered in the wetter months, indicating a strong dependency on water availability. NDVI and EVI were positively associated with GPP (r = 0.69 and 0.81, respectively), suggesting a coupling between the emergence of new leaves and the phenology of local photosynthetic capacity. WUE, on the other hand, was strongly controlled by consecutive dry days and not necessarily by total precipitation amount. The vegetation indices adequately described interannual variations of the forest response to environmental factors, and GPP MODIS presented a good relationship with tower-measured GPP in dry (R² = 0.76) and wet (R² = 0.62) periods.

Common bean is usually cropped under rainfed conditions and in soils with low pH and water retention, in the sub-humid and semiarid regions of Brazil. To improve soil conditions, smallholder farmers commonly use cattle manure. However, manure is available in limited amounts, insufficient to fertilize all cropping areas. Thus, other amendments, such as poultry manure (PM) and biochar (BC), have been proposed to increase soil water retention and pH. We evaluated the effects of BC (10, 20, and 40 t ha⁻¹; BC10, BC20, and BC40, respectively), PM (5 t ha⁻¹; PM), the combination of both amendments (BC10 + PM, BC20 + PM, and BC40 + PM) and an absolute control (Control), with no amendment, on soil physical, chemical, and biological properties, and on common bean water use efficiency (WUE) and yield. The treatments had no effects on total organic carbon, cation exchange capacity, microbial biomass carbon, soil physical properties, and evapotranspiration. Treatment combination BC (10 t ha⁻¹) + PM (5 t ha⁻¹) significantly improved phosphorus concentration, enzymatic activities, WUE, and bean yield in this one-year experiment and it can be a viable management practice for smallholder farmers in the Brazilian sub-humid region. However, further investigations are required to study the long-term field effects of the best performing soil amendments.