Seeding blue grama in old crested wheatgrass fields in southwestern Saskatchewan.

Abstract

Crested wheatgrass [Agropyron cristatum (L.) Gaertn.] fields have low plant diversity and a limited grazing season. We tested whether blue grama [Bouteloua gracilis (HBK.) Lag.] could be established in crested wheatgrass fields to increase plant diversity and grazing season length. Three seeding methods (unseeded, seed broadcast after rototilling, or seed drilled) and 2 herbicide treatments (none or glyphosate [N (phosphonomethyl)-glycine] sprayed at 1.1 kg a.i. ha-1) were applied in a complete factorial design to 3 X 10 m plots in 1994 in two 50 year-old crested wheatgrass stands. Blue grama established in seeded plots, but the effectiveness of seeding methods varied between sites. At both sites, herbicide control of crested wheatgrass greatly promoted the establishment of blue grama. Crested wheatgrass biomass and cover were reduced by rototilling and by spraying. The results suggest that the establishment of blue grama in crested wheatgrass stands is possible if seed is added and competition from crested wheatgrass is controlled.