In this study bluebunch wheatgrass (Agropyron spicatum) plants were clipped at four different phenological stages to compare forage quality of subsequent regrowth relative to nondefoliated plants. Following two years of treatment, plants clipped at the boot, emergence, flowering, and seed formation produced lower levels of acid detergent fiber (ADF) and higher values of crude protein (CP) and P than control plants at equivalent phenological stages. Clipping at boot and emergence for 2 years delayed flowering by 16 and 15 days , respectively, while subsequent flowering of plants clipped at flowering and seed formation occurred only sporadically. Greater increases in forage quality were achieved when bluebunch wheatgrass was clipped later in the season but the authors also recognize that late season defoliation damages plants and reduces seed production. The results of this study suggest that spring defoliation of bluebunch wheatgrass plants increases the forage quality of these plants for winter elk grazing, however, the authors also caution that spring grazing may negatively impact grassland health and may not produce similar effects at all grassland sites.
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