Evapotranspiration from a Greasewood‐Cheatgrass community

Abstract

Groundwater elevation, soil moisture, and precipitation were monitored to evaluate the components of water loss from two greasewood‐cheatgrass ( Sarcobatus vermiculatus‐Bromus tectorum ) communities in south central Washington. Annual evapotranspiration was 21–25 cm, 18–31% of which was the transpiration of groundwater. The greatest loss from the system was the evapotranspiration of stored soil moisture, but this moisture was unavailable to greasewood. This study confirms that water use rates are a function of depth to water up to 2.3 meters, but indicates a more complicated mechanism at depths of up to 13 meters. Shrub height, canopy coverage, and total leaf surface area are inversely related to depth to water, and the rate of water use is in turn directly related to these plant‐associated features.