National Library of Energy BETA

Sample records for bluestem andropogon gerardii

  1. Do yield and quality of big bluestem and switchgrass feedstock decline over winter?

    SciTech Connect (OSTI)

    Jane M.F. Johnson; Garold L. Gresham


    Switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerdardii Vitman) are potential perennial bioenergy feedstocks. Feedstock storage limitations, labor constraints for harvest, and environmental benefits provided by perennials are rationales for developing localized perennial feedstock as an alternative or in conjunction with annual feedstocks (i.e., crop residues). Little information is available on yield, mineral, and thermochemical properties of native species as related to harvest time. The study’s objectives were to compare the feedstock quantity and quality between grasses harvested in the fall or the following spring. It was hypothesized that biomass yield may decline, but translocation and/or leaching of minerals from the feedstock would improve feedstock quality. Feedstock yield did not differ by crop, harvest time, or their interactions. Both grasses averaged 6.0 Mg ha-1 (fall) and 5.4 Mg ha-1 (spring) with similar high heating value (17.7 MJ kg-1). The K/(Ca + Mg) ratio, used as a quality indicator declined to below a 0.5 threshold, but energy yield (Megajoule per kilogram) decreased 13% by delaying harvest until spring. Only once during the four study-years were conditions ideal for early spring harvest, in contrast during another spring, very muddy conditions resulted in excessive soil contamination. Early spring harvest may be hampered by late snow, lodging, and muddy conditions that may delay or prevent harvest, and result in soil contamination of the feedstock. However, reducing slagging/fouling potential and the mass of mineral nutrients removed from the field without a dramatic loss in biomass or caloric content are reasons to delay harvest until spring.

  2. Gene expression patterns of two dominant tallgrass prairie species differ in response to warming and altered precipitation


    Smith, Melinda D.; Hoffman, Ava M.; Avolio, Meghan L.


    To better understand the mechanisms underlying plant species responses to climate change, we compared transcriptional profiles of the co-dominant C4 grasses, Andropogon gerardii Vitman and Sorghastrum nutans (L.) Nash, in response to increased temperatures and more variable precipitation regimes in a long-term field experiment in native tallgrass prairie. We used microarray probing of a closely related model species (Zea mays) to assess correlations in leaf temperature (Tleaf) and leaf water potential (LWP) and abundance changes of ~10,000 transcripts in leaf tissue collected from individuals of both species. A greater number of transcripts were found to significantly change in abundance levelsmore » with Tleaf and LWP in S. nutans than in A. gerardii. S. nutans also was more responsive to short-term drought recovery than A. gerardii. Water flow regulating transcripts associated with stress avoidance (e.g., aquaporins), as well as those involved in the prevention and repair of damage (e.g., antioxidant enzymes, HSPs), were uniquely more abundant in response to increasing Tleaf in S. nutans. Furthermore, the differential transcriptomic responses of the co-dominant C4 grasses suggest that these species may cope with and respond to temperature and water stress at the molecular level in distinct ways, with implications for tallgrass prairie ecosystem function.« less

  3. Bridging the Divide: Linking Genomics to Ecosystem Responses to Climate Change: Final Report

    SciTech Connect (OSTI)

    Smith, Melinda D.


    Over the project period, we have addressed the following objectives: 1) assess the effects of altered precipitation patterns (i.e., increased variability in growing season precipitation) on genetic diversity of the dominant C4 grass species, Andropogon gerardii, and 2) experimentally assess the impacts of extreme climatic events (heat wave, drought) on responses of the dominant C4 grasses, A. gerardii and Sorghastrum nutans, and the consequences of these response for community and ecosystem structure and function. Below is a summary of how we have addressed these objectives. Objective 1 After ten years of altered precipitation, we found the number of genotypes of A. gerardii was significantly reduced compared to the ambient precipitation treatments (Avolio et al., 2013a). Although genotype number was reduced, the remaining genotypes were less related to one another indicating that the altered precipitation treatment was selecting for increasingly dissimilar genomes (based on mean pairwise Dice distance among individuals). For the four key genotypes that displayed differential abundances depending on the precipitation treatment (G1, G4, and G11 in the altered plots and G2 in the ambient plots), we identified phenotypic differences in the field that could account for ecological sorting (Avolio & Smith, 2013a). The three altered rainfall genotypes also have very different phenotypic traits in the greenhouse in response to different soil moisture availabilities (Avolio and Smith, 2013c). Two of the genotypes that increased in abundance in the altered precipitation plots had greater allocation to root biomass (G4 and G11), while G1 allocated more biomass aboveground. These phenotypic differences among genotypes suggests that changes in genotypic structure between the altered and the ambient treatments has likely occurred via niche differentiation, driven by changes in soil moisture dynamics (reduced mean, increased variability and changes in the depth distribution of

  4. OneTouch 4.0 Scanned Documents

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    ... Broomsedge (Andropogon virginicus), dominant for the past several years, is still very common but is now more widely scattered in its distribution. Poverty grass (Aristida ...

  5. The initial phase of a Longleaf Pine-Wiregrass Savanna restoration: species establishment and community responses.

    SciTech Connect (OSTI)

    Aschenbach, Todd, A; Foster, Bryan, L.; Imm, Donald, W.


    AbstractAbstract The significant loss of the longleaf pine-wiregrass ecosystem in the southeastern United States has serious implications for biodiversity and ecosystem functioning. In response to this loss, we have initiated a long-term and landscape-scale restoration experiment at the 80,125 ha (310 mi2) Department of Energy Savannah River Site (SRS) located near Aiken, South Carolina. Aristida beyrichiana (wiregrass), an important and dominant grass (i.e., a matrix species) of the longleaf pine savanna understory, and 31 other herbaceous non-matrix species were planted at six locations throughout SRS in 2002 and 2003. Of the 36,056 transplanted seedlings, 75% were still alive in June 2004, while mean 12 year survival across all planted species was 48%. Lespedeza hirta (hairy lespedeza) exhibited the greatest overall survival per 3 3 m cell at 95%, whereas Schizachyrium spp. (little bluestem) exhibited the greatest mean cover among individual species at 5.9%. Wiregrass survival and cover were significantly reduced when planted with non-matrix species. Aggregate cover of all planted species in restored cells averaged 25.9% in 2006. High rates of survival and growth of the planted species resulted in greater species richness (SR), diversity, and vegetative cover in restored cells. Results suggest that the loss of the longleaf pine-wiregrass ecosystem may be ameliorated through restoration efforts and illustrate the positive impact of restoration plantings on biodiversity and vegetative cover.

  6. Final Technical Report

    SciTech Connect (OSTI)

    Sara Bergan, Executive Director; Brendan Jordan, Program Manager; Subcontractors as listed on the report.


    can be done in such a way that also maximizes or improves upon conservation and other environmental goals (in some cases even when compared to idled land); Switchgrass and big bluestem work well together in simple mixture plots where big bluestem fills in around the switchgrass which alone grows in bunches and leaves patches of bare soil open and susceptible to erosion; Longer-term studies in the northern plains may also find that every other year harvest schemes produce as much biomass averaged over the years as annual harvests; Grasses can be grown for between $23 and $54/ton in the northern plains at production rates between 3 and 5 tons/acre; Land costs, yields, and harvest frequency are the largest determining factors in the farm scale economics. Without any land rent offset or incentive for production, and with annual harvesting, grass production is likely to be around $35/ton in the northern plains (farm gate); Average transportation costs range from $3 to $10/ton delivered to the plant gate. Average distance from the plant is the biggest factor - $3/ton at 10 miles, $10/ton at 50 miles; There is a substantial penalty paid on a per unit of energy produced basis when one converts grasses to bio-oil, but the bio-oil can then compete in higher priced fuel markets whereas grasses alone compete directly with relatively cheap coal; Bio oil or modified bio-oil (without the HA or other chemical fraction) is a suitable fuel for boiler and combustion turbines that would otherwise use residual fuel oil or number 2 diesel; Ensyn has already commercialized the use of HA in smokey flavorants for the food industry but that market is rather small. HA, however, is also found to be a suitable replacement for the much larger US market for ethanolamines and ethalyne oxides that are used as dispersants; Unless crude oil prices rise, the highest and best use of grass based bio-oil is primarily as a direct fuel. As prices rise, HA, phenol and other chemical fractions may become more