Submitted to: Journal of Sustainable Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2008
Publication Date: 7/1/2009
Citation: Woodis, J.E., Brink, G.E., Cates, R.L., Jackson, R.D. 2009. Effects of Native Grass Restoration Management on Above- and Belowground Pasture Production and Forage Quality. Journal of Sustainable Agriculture. 33:512-527.
Interpretive Summary: The loss of tallgrass prairie in the USA has motivated research into how to best facilitate re-introduction of native species, including attempts to seed prairie species into cool-season pastures. Our objective was to assess forage production and quality of cool-season pastures subjected to native grass restoration management. Pasture blocks were grazed or burned (April) for two years. Grazed or burned plots were seeded with a mixture of big bluestem, switchgrass, and indiangrass. The soil was then amended with three treatments: no treatment, N fertilization (60 kg N ha-1), or carbon addition (1.2 kg sawdust m-2). We found that soil amendment did not effect the yield of burned plots, but nitrogen fertilization increased the annual yield of grazed plots compared to adding carbon. In both grazed and burned plots, most forage quality changes were ascribed to factors outside the control of farmers, such as season. The results showed no consistent effect of restoration management on pasture production or quality. They highlight the complexity of grassland agroecosystems and demonstrate the importance of evaluating the variability of treatment effects over time.
Technical Abstract: Multifunctional agricultural landscapes and the ecosystem services they provide are gaining more attention. One example of this is the reintroduction of native species to cool-season grassland agroecosystems managed for livestock production. While such projects have potential ecological and agronomic benefits, there is little information on how restoration type management affects pasture production and quality. The objective of this study was to determine how management to establish native warm-season grasses into temperate pastures affects forage production and quality. We tested this over three years (2004 through 2006) using a field experiment with combinations of disturbance (burning and grazing), soil amendments (ambient, nitrogen, and carbon), and native grass seeding times (fall and spring). We measured aboveground net primary production (ANPP), belowground net primary production (BNPP), and two forage quality parameters—neutral detergent fiber and in vitro neutral detergent fiber digestibility. For ANPP, there was a significant disturbance × soil amendment interaction effect in each year, but the nature of the interaction varied by year. In 2005, plots where nitrogen was applied had lower BNPP than carbon and ambient plots. In 2006, burned plots had greater BNPP than grazed plots. For each level of disturbance, over 50% of the variability in the forage quality parameters was attributed to non-management variables, such as season. Our results showed no consistent effect of restoration management on pasture production or quality. They highlight the complexity of grassland agroecosystems and demonstrate the importance of evaluating the variability of treatment effects over time.