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

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 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 513 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.

Testing Disturbance, Seeding Time, and Soil Amendments for Establishing Native Warm‐Season Grasses in Non‐Native Cool‐Season Pasture

“…3). Aboveground NPP was not lowered by C addition from 2004 through 2006; in 2006, burned plots had greater BNPP than grazed plots (Doll et al 2009). …”

“…The best predictor of 2006 and 2007 native grass tiller density was 2006 BNPP, which was greater in burned plots (Doll et al 2009). Our methods do not allow us to attribute the increase in BNPP to either C3 or C4 grasses.…”

“…This was repeated five times at 10-m intervals for a total of 50 hits per experimental unit. Annual aboveground net primary production (ANPP) was calculated as the sum of monthly differences in biomass between the inside and outside of grazing-exclusion cages during the growing season of 2004 and then from allometric relationships between biomass and leaf area index in 2005 and 2006 (Doll et al 2009). Belowground net primary production (BNPP) was determined in 2005 and 2006 using root in-growth cores (Bledsoe et al 1999); detailed methods described in Doll et al (2009).…”

Biodiversity, photosynthetic mode, and ecosystem services differ between native and novel ecosystems

“…The method consisted of dropping 1-m-long pins perpendicular to the ground at each outside corner of a 20 × 50-cm frame in 25 randomly sampled locations (totaling 100 pin drops per site), and counting the number of pin hits per species. species were designated as either native or exotic using national references when possible (49 % of species) (Flora of north america 1993), and regional references for the rest (Great Plains Flora association 1986; Gleason and cronquist 1991; eilers and roosa 1994; Diggs et al 1999;yatskievych 2006). We were unable to identify 3 % of species to c 3 or c 4 status and 5 % of species to native or exotic status based on the available plant material, and these were removed from proportion c 3 and proportion exotic variables, respectively.…”

“…List of species used in the experiment. All species are already present in the Texas flora (Diggs et al 1999). Nine-species plots were planted with random draws from the following list of C 4 grasses, C 3 grasses, C 3 forbs, and C 3 leguminous forbs, with all functional groups represented in each plot.…”