Influence of Competition on the Response of Bluebunch Wheatgrass to Clipping

Abstract

Partial reduction of competition from surrounding vegetation more than doubled the total herbage and tripled the number of flower stalks produced the following year by bluebunch wheatgrass (Agropyron spicatum). Elimination of competition resulted in a sixfold increase in herbage production and a tenfold increase in number of flower stalks. The relative depressant effects of clipping were significantly reduced by concurrent reductions in competition. The beneficial effects of partial reduction of competition offset the adverse effects of heavy clipping, and elimination of competition more than offset the effects of extreme clipping. Number of flower stalks is a more sensitive indicator of vigor than total herbage production. Average flower stalk and foliage culm lengths are not useful indicators of vigor.