Potential of Warm-Season Annual Pastures in Rotation with Corn Silage for Organic Dairies.

Complementing cool-season pastures with warm-season pastures can provide a more even pasture availability throughout the grazing season. Increased and constant pasture availability is especially important for organic producers because of the newly defined grazing requirement for organic dairy. Using warm-season annual grasses in rotation with corn silage allows dairy farmers to increase their available pasture without exchanging a field for perennial pasture. The objectives of this study were to assess the productivity of annual pastures and their effect on following corn yield, to compare overall yield and nutritional quality of cool-season perennial pasture with warm-season annual pastures rotated to corn silage, and to compare farm profitability along a gradient of warm-season annual pasture inclusion. Cool-season perennial pasture treatments included red clover in monoculture and in a mixture with orchardgrass. Annual pastures were comprised of warm-season grasses, sorghum-sudangrass and teff, and red clover in monoculture or mixed stands of two and three species. The red clover monoculture and annual pastures were rotated to silage corn. Yield and quality of warm-season pastures differed significantly between treatments. The yield and forage quality was highest for sorghum-sudangrass and teff mixture and sorghum-sudangrass monoculture, and, compared to the cool-season perennial pastures, had higher or comparable digestibility. Preliminary data suggests that the yield of corn silage was not affected by the annual pastures. Initial results also indicate that warm-season annual pastures rotated to corn silage yields similarly to two years of cool-season perennial pastures. These results will be confirmed this field season. Finally, models for farm profitability at different proportions of land in perennial and annual pastures are currently being developed.