## 3 Results
### Capabilities and limitations of VTM-Forecasted Transpiration for Sugarane Plantations  
The correlation between ET\({}_{\text{EC}}\) and T\({}_{\text{VTM}}\) for the Brazil site was moderate for the T\({}_{\text{VTM\_EC}}\) model (R\({}^{2}\) = 0.47) but exhibited lower values for T\({}_{\text{VTM\_MOD}}\) (R\({}^{2}\) = 0.009) and T\({}_{\text{VTM\_LS-S2}}\) (R\({}^{2}\) = 0.21), indicating that further improvement and additional variables should be considered in sites located in tropical environments like the Brazil site, where elements such as the residual straw and Bowen ratio variability can affect the transpiration and evapotranspiration rates [152], whereas the more wider spaced rows in Louisiana (1.5 m single row compared to 1.83 m single row and 2.4 m double row) could have affected these water rates [153]. Conversely, the USA site showed a robust correlation across all VTM estimates, especially for the high-spatial-resolution T\({}_{\text{VTM\_LS-S2}}\) (R\({}^{2}\) = 0.61), which outperformed the estimates calculated using the GPP\({}_{\text{EC}}\) data as an input for the VTM. The observed differences could be attributed to various factors, including the climatic conditions, soil properties, row spacing, data quality, and sugarcane varieties.  
The annual total data in Table 4 underscore the inherent variability in precipitation, ET\({}_{\text{EC}}\), and T\({}_{\text{VTM}}\) across the sites. Ref. [154] highlighted the changes in actual evaporation and transpiration linked to climate change as one of the leading factors in the interannual yield variability of sugarcane in Brazil. The USA site exhibited the largest interannual variation in precipitation, ET\({}_{\text{EC}}\), and transpiration VTM rates. Ref. [155] emphasized the impact of soil water conditions as the main driver of the interannual variability in ET and T, partially explaining some the differences observed in the T\({}_{\text{VTM}}\):ET\({}_{\text{EC}}\) ratios over time. Moreover, ref. [156] addressed the significance of row spacing, as it increases soil water content and provides more space for the sugarcane to grow, significantly increasing transpiration in periods of low rainfall, which could partially explain some of the abnormally high T\({}_{\text{VTM}}\) rates at the USA site in 2020 (driest year). In addition, some of the differences between the MSR and HSR transpiration estimates can be linked to the fact that the MSR pixel included multiple fields containing different varieties and, in some cases, different management practices.  
The VTM showed a strong capacity to capture the seasonal dynamics and some of the interannual variability in the transpiration rates. Despite the simplicity of the approach, overall, the T\({}_{\text{VTM}}\) results captured the seasonal dynamics of the water flux, underscoring the potential of this tool and its applications. However, the variability across different scales in the results suggests that for field-level and commercial applications the time-scale dependency should be further studied, and additional parameters such as initial water content and row spacing should be included to provide a better field representation of the transpiration water flux.