Limited impact of vapor pressure deficit on rainfed maize evapotranspiration, CO2 flux, and canopy temperature

Recent studies have suggested that increasing growing season vapor pressure deficit (vpd) will result in greater crop water use and more frequent water stress in rainfed maize (Zea mays L.). In this 3‐year study, we used flux tower and biometeorological measurements to examine the impact of diurnal variability of vpd and other climate parameters on latent heat (LE), sensible heat (H) and CO2 fluxes, and canopy temperature in field‐grown maize at non‐stress (high) and stress (low) volumetric soil water contents (SWC). Increases in vpd impacted LE primarily through midday when both net radiation (Rn) and vpd are increasing but vpd can still be low enough (