PROPOSAL
Submitted to: Wyoming Carbon Sequestration Advisory Committee
Project Title: Determination of Soil Carbon Sequestration in Big Sagebrush Rangeland Ecosystems of Wyoming
Principal Investigators: Justin D. Derner1, Gerald (Jerry) E. Schuman2, and George F. Vance3
1
Rangeland Scientist, USDA-Agricultural Research Service, High Plains Grasslands Research
Station, Cheyenne, WY; 2Soil Scientist (retired), USDA-Agricultural Research Service, High Plains Grasslands Research Station, Cheyenne, WY; and 3Professor, University of Wyoming, Department of Renewable Resources, Laramie, WY
Requested Amount of Funding: $14,710 Duration: October 1, 2008 – September 30, 2010
Introduction Increasing societal emphasis on desired ecosystem goods and services from western rangelands such as carbon sequestration, combined with the emerging development of state-and-transition models describing vegetation change and associated ecological processes, functions and resilience of these systems provides the framework to effectively provide needed scientific results that address a multitude of questions. For example, soil carbon sequestration may not only mitigate the rise in atmospheric carbon dioxide concentration, but also provide ecosystem co-benefits of improved soil quality and increased infiltration capacity. Unfortunately, scientific information regarding soil carbon sequestration in western rangelands, especially those with a big sagebrush component and in lower rainfall areas (<14 inches), is lacking. Rationale/Justification Recent (April 2007) efforts by a scientific advisory panel to the Chicago Climate Exchange (http://www.chicagoclimatex.com/) resulted in a Rangeland Soil Carbon Offset Program, but this program does not include lands on which big sagebrush is a major plant species because of the lack of published scientific data. Sagebrush rangelands represent much of central and southwestern Wyoming (see below); hence, producers with lands in this geographic area are not eligible to participate in this offset program, and receive financial payments for possible soil carbon sequestration from these lands.
The Major Land Resource Area (MLRA) of interest would be 34A which covers most of the south central and western portions of Wyoming (see below)
Collection and subsequent carbon analyses of soil samples from key representative ecological sites and major land management practices (e.g., brush management) within Major Land Resource Area 34A would provide needed data that could be presented to the Chicago Climate Exchange in an effort to qualify rangelands big sagebrush rangeland ecosystems for the Offset Program. In addition, quantification of soil carbon from big sagebrush plant communities representing different vegetation states (i.e., vegetation change) associated with management practices (e.g., grazing, brush management) would provide valuable information for inclusion into developed state-and-transition models for ecological site descriptions. Ecological Sites With the generous assistance of Karen Clause (USDA-Natural Resource Conservation Service (NRCS), Pinedale), we have identified Major Land Resource Area (MLRA) 34A (Cool central desertic basins and plateaus, see above) as the primary area of interest because of its geographical extent, precipitation levels, and prevalence of big sagebrush. Within this MLRA, Karen has suggested that there are 2 primary ecological sites that represent large acreages and presently have developed state-and-transition models. These include Sandy 7-9GR and Loamy 10-14W. Within each of these ecological sites, the developed state-and-transition vegetation models (see below) have 3 plant communities where big sagebrush is prominent. However, we do not plan to sample the rabbitbrush/rhizomatous wheatgrass plant community in either ecological site.
Selection of plant communities from October 14 field site visit Karen and Marion Burgin (USDI-Bureau of Land Management (BLM), Kemmerer) met with Jerry Schuman and Justin Derner on October 14, 2008 to view potential field sites in Lincoln County. Representative plant communities for each of the vegetation states with big sagebrush (green boxes in the diagrams above in each of the ecological sites) were located along with previously applied BLM management practices (brush management) within which we will establish replicated transects for soil sampling and vegetation measurements (cover, density, production). This sampling design will provide adequate statistical power and robustness of experimental design for publication of results in scientific journals that would be acceptable to the Chicago Climate Exchange. Two distinct sampling areas were chosen with one (Fontanelle) representing the Sandy 7-9GR ecological site and the other (Cow Hollow) representing the Loamy 10-14W ecological site. At the Fontanelle area (see Appendix 1 for a map), 2 groups of treatment sites were selected. The first group consists of: 1) big sagebrush with bare ground (control, see Appendix 2) 2) big sagebrush with bunchgrass, and 3) reduced big sagebrush due to a 2002 mowing treatment and increased rhizomatous grasses (Appendix 3). The second group of treatment sites is directly across a fence to the southwest with: 1) big sagebrush with bare ground (control) and 2) a bunchgrass-dominated site with limited big sagebrush due to a 2002 mowing. At the Cow Hollow area (east of Opal), 2 groups of treatment sites were also selected. Each group has a control site which is mixed grass and big sagebrush. The other two treatments have reduced big sagebrush and increased rhizomatous grasses due to 1) a 1997 application of the herbicide Spike (1 pound/acre) and 2) a 1997 mowing. Materials and methods Our field methods for obtaining soil samples have been used extensively in prior experiments conducted on rangelands in eastern Wyoming. In prior field experiments, we have established 2 randomly located 50 m transects within the desired plant communities. For each transect, we will determine density (number of plants) and foliar cover of big sagebrush and herbaceous grasses along 1-m wide belt transect in late August/early September 2009. Biomass production will be estimated at the same time from destructive harvests of plants within each of 4 temporary 1 m2 grazing exclosures randomly located along each of the transects. These estimates of density, cover and aboveground biomass production of big sagebrush and herbaceous grasses will be used to scale up the soil carbon and nitrogen values obtained to a plant community basis. Soil samples will be collected in late May/early June 2009 at 5 locations along each transect (0, 10, 20, 30 and 40 m) using a hydraulic soil sampler (Giddings mounted on the 3-point of a small John Deere tractor). We will take 2 soil cores (each 3 cm inside diameter) to a 60 cm depth at each location along each transect. One of these cores will located at the dripline of the nearest big sagebrush plant and the other core will be taken in the grass component (or bare ground if that is the represented community) between sagebrush plants. At the 10 and 30 m locations along each transect 2 additional soil cores will be taken (both at the dripline and between sagebrush plants) for determinations of soil bulk density to convert concentrations of soil nitrogen and carbon to mass values. After soils are cored, they are separated in the field into 0-5, 5-15, 15-30, and 30-60 cm increments, placed in Ziploc bags for transportation back to our laboratory for removal of roots, grinding of soils and chemical analyses using standardized methods. We are estimating the following number of total soil samples to analyze for carbon and nitrogen:
Fontanelle area (Sandy 7-9GR ecological site) 5 treatment sites (2 controls, big sagebrush with bunchgrass, 2 mowing treatments) 2 transects per site 5 locations per transect Sagebrush and grass (or bare ground) location 4 depths (0-5, 5-15, 15-30, and 30-60 cm) Total of 100 soil sampling locations and 400 soil samples (due to 4 depths)
Cow Hollow area (Loamy 10-14W ecological site) 4 treatment sites (2 controls, 1 herbicide Spike treatment, 1 mow treatment) 2 transects per site 5 locations per transect Sagebrush and grass (or bare ground) location 4 depths (0-5, 5-15, 15-30, and 30-60 cm) Total of 80 soil sampling locations and 320 soil samples (due to 4 depths) Total of 180 soil sampling locations for the entire project and 720 soil samples Justin Derner, Jerry Schuman and Matt Mortenson (USDA-ARS technician) will collect the soil samples in spring 2009 (likely late May/early June). Matt will be the lead technician responsible for the preparation and analyses of the soil samples, with assistance from an hourly student worker. Justin Derner and Matt Mortenson will be responsible for leading the vegetation data collection in late August/early September 2009. Justin Derner, Jerry Schuman and George Vance will be responsible for the statistical analyses of the data, the writing of manuscripts and the publication of the data in scientific journals as well as oral presentations.
Estimated Budget Item Field travel to sites and per diem (27 person days @ $110/day) Sample preparation/processing/analyses (720 @ $7/sample) Hourly student worker (450 hours @ $10/hour) Contract labor (40 hours @$25/hour) Publication Costs (2 papers @ $600 each) TOTAL REQUEST In-kind Contributions Item Salary – Justin Derner (2 months) Salary – Matt Mortenson (3 months) Salary – George Vance (1 month) TOTAL Cost $15,800 $13,120 $10,214 $39,134 Cost $2,970 $5,040 $4,500 $1,000 $1,200 $14,710
Appendix 1 – Fontanelle study area GPS coordinates for sampling sites
Appendix 2 – Control sampling site in Fontanelle area – Big sagebrush with bare ground
Appendix 3 – Mowed sampling site in Fontanelle area with reduced Big sagebrush and increased rhizomatous grasses
Appendix 4 – Cow Hollow study area GPS coordinates for sampling sites