Data Supporting the Manuscript "Patch Mow Grazing: Uncovering the Feedbacks Between Defoliation, Biomass, and Nutritive Value in a Mowed and Grazed Landscape"

The forage maturation hypothesis states that as biomass increases and vegetation matures, its nutritive value decreases—and it is thought that herbivores respond accordingly. Specifically, herbivores disproportionately select for recently defoliated landscape patches that are greater in nutritive value and lower in biomass compared to those with greater biomass and longer time since defoliation. However, most studies only address narrow ranges of defoliation, comparing intensely defoliated sites (<10 cm) to those that are not defoliated—or have a much longer time since defoliation—in landscapes managed with fire and gazing, largely overlooking other methods of defoliation, such as mowing at different heights. We conducted this study to examine how patch-mow grazing affects nutritive value by investigating the relationships between: (1) mowing height and nutritive value, and (2) biomass and nutritive value in a recently defoliated landscape. Nutritive value was significantly greater in short-mown patches (5 cm) compared to other patch heights (18 cm to 30+ cm), while biomass was inversely related to nutritive value and digestibility regardless of treatment. Our results suggest that herbivores grazing in areas with greater biomass receive less nutrition, likely limiting their performance throughout the growing season compared to those grazing in recently defoliated shorter patches with less biomass, and greater nutritive value. Therefore, management methods which rotate cattle from low-biomass, high-quality areas to those with high-biomass, but low-quality, are likely to reduce animal performance, and may increase supplement costs over time. Patch-mow grazing has the potential to increase livestock production and promote grassland heterogeneity critical to sustainable livestock production across the Great Plains.