Influence of vineyard row orientation on evapotranspiration estimates using a two-source energy balance model

Authors: SALAZAR-MARTÍNEZ, DIEGO - Orise Fellow; Knipper, Kyle; Kustas, William; BAMBACH, NICOLAS - University Of California, Davis; PONCE DE LEON, MARÍA - University Of California, Davis; CASTRO, SEBASTIAN - University Of California, Davis; Tolentino, Peter; Prueger, John; Alfieri, Joseph; McKee, Lynn; Anderson, Martha; Gao, Feng; WRIGHT, IAN - University Of California, Davis; GAL, ANDREW - University Of California, Davis; McElrone, Andrew

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2025
Publication Date: 11/14/2025
Citation: Salazar-Martínez, D., Knipper, K.R., Kustas, W.P., Bambach, N., Ponce de Leon, M.A., Castro, S., Tolentino, P.M., Prueger, J.H., Alfieri, J.G., McKee, L.G., Anderson, M.C., Gao, F.N., Wright, I.R., Gal, A., McElrone, A.J. 2025. Influence of vineyard row orientation on evapotranspiration estimates using a two-source energy balance model. Agricultural Water Management. 322. Article 109976. https://doi.org/10.1016/j.agwat.2025.109976.
DOI: https://doi.org/10.1016/j.agwat.2025.109976

Interpretive Summary: Farmers in dry regions like California need to be very careful about how they use water. One factor that can influence how much water crops need is the direction in which the crop rows are planted. While researchers have studied typical row orientations (north-south or east-west), much less is known about rows planted at angles, such as southwest–northeast (SWNE) or northwest–southeast (NWSE). In this study, we used computer models, satellite data, and on-the-ground measurements to see if row direction affects water use in vineyards. We found that during the growing season, vineyards with rows planted SWNE consistently used more water than those planted NWSE. The difference was linked to how the rows intercept sunlight and create shadows, which can influence how much water the plants take up. These results can help farmers and vineyard managers design their fields and irrigation schedules in ways that use water more efficiently. This information is especially important for high-value crops in areas where water is scarce. While the study focused only on water use, row orientation could also influence crop quality and yield, which may be explored in future research.

Technical Abstract: Understanding and quantifying the influence of crop row orientation in canopy radiation interception and water uptake can help enhance irrigation schedules and water management strategies. This is valuable for high-value-crop farms located in water-limited regions, such as California vineyards. Although some scientific literature addresses this for typical row orientations (i.e., North-South and East-West), Southwest-Northwest (SWNE) and Northwest-Southeast (NWSE) row orientations remain largely unaccounted for. In this study, Two-Source Energy Balance (TSEB) model simulations are performed during 2021 and 2022 to quantify the differences in evapotranspiration (ET) between vineyard blocks oriented SWNE and NWSE. Simulated daily ET rates are similar before the vine growing season, but consistently higher for SWNE blocks during the growing seasons (1.2 ±0.36 (mm day-1) in 2021 and 1.5 ±0.55 (mm day-1) in 2022, on average). Eddy covariance measurements confirm the ET separation between row orientations, but the differences are generally smaller. Satellite-based LAI, LST and albedo forcing inputs to TSEB also display differences that start with the vine growing season. A sensitivity analysis suggests that the latter two highly correlate (r2 = 0.88 and r2 = 0.86, respectively) with modelled ET differences. Simulations with two radiative transfer models indicate a greater canopy radiation interception and shadows in SWNE blocks throughout the growing season. The shadow differences are likely captured by the satellite-based TSEB inputs, thus having potential to be a proxy for row orientation effects on vine water consumption. The results of this study add to the comprehensive and quantitative understanding of row geometry influence on crop water uptake needed to improve ET models estimates, and to inform the design of field and ranch architectures that increase crop water use efficiency. Row orientation may also ultimately affect crop quality or yield but is not considered in this study.