Energy Balance Comparisons of Wide and Narrow Row Spacings in Sorghum 1

A sorghum ( Sorghum bicolor L. Moench.) canopy has been described as a wick; hence, its evapotranspiration would depend to a large extent on its energy supply. The objective of this study was to determine the effect of row spacing on the energy balance of sorghum. Measurements were made on wide (0.92 m) and narrow (0.46 m) spaced rows of sorghum with equal linear plant density (12 plants/m). Evapotranspiration (lysimeter), net radiation, and soil heat flux were measured. Sensible heat flux was obtained as a residual in the energy balance. Seasonal evapotranspiration was about 10% more from wide row than from narrow row sorghum. High rates of evapotranspiration were maintained on wide row sorghum by row advection during the first part of the growing season and large‐scale advection during the latter part of the growing season. This study suggests that sensible heat and, consequently, evapotranspiration can be reduced by narrow row spacing in sorghum.