Moisture Interception as a Factor in the Competitive Ability of Bluebunch Wheatgrass

Abstract

Aerial parts of the caespitose type of bluebunch wheatgrass (Agropyron spicatum) have been shown to direct rainwater and to concentrate it in the soil immediately beneath individual plants. The degree to which water collects beneath the bunches appeared to be related to the size of the canopy. It is possible that the rapid decline of bluebunch wheatgrass under heavy grazing is related to soil moisture redistribution caused by the removal of its aerial parts.