Effects of Native Grass Restoration Management on Above- and Belowground Pasture Production and Forage Quality.

摘要

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 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.