Using GIS to Assess Virginia

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Using GIS to Assess Virginias Best Options for
Sequestering Carbon through Land-Use Management
Jeffrey Galang1, Carl Zipper1, Stephen Prisley2,
John Galbraith1 and Randolph Wynne2Virginia
Tech Department of Crop and Soil Environmental
Sciences1Virginia Tech Department of Forestry2
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Objectives

• Identify the most promising terrestrial carbon
  sequestration options for Virginia
• Carbon sequestration rates per ecoregion
• Statewide totals
• Develop a statewide database of relevant spatial
  information
• Elevation (30m), National Land Cover Data (1992),
  State Soil Geographic Data, conservation tillage
  data (NASS/CTIC), National Hydrography Data (med.
  resolution), and boundaries (county and
  ecoregion)
• Assess the regional carbon sequestration
  potential for three land-use changes
• Option A Afforestation of marginal agricultural
  lands
• Option B Conversion of conventional tillage (CT)
  crops to no-till (NT) crops
• Option C Afforestation of agricultural lands
  within riparian areas

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Level III Ecoregions of Virginia
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Methods (Option A Marginal Lands Afforestation)

• Identify marginal lands for agriculture
• Productivity limitations (e.g. flooding, hydric,
  rocky, droughty, etc.)
• Highly erodible (Erodibility Index 8)
• Steep gradients (frequency distribution, gt95)
• Overlay with map of agricultural lands
  (pasture/hay and row crops)
• Obtain C sequestration potentials (20, 40, and 80
  years) from STATSGO WOODPROD and empirical yield
  tables (McClure and Knight, 1984 Brown and
  Schroeder, 1999)
• Overlay C sequest. potentials with marginal ag.
  lands
• Calculate total carbon sequestered by ecoregion

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Methods (Option B Conservation Tillage)

• Calculate area (m2) of each county in wheat,
  soybean, and corn production (NASS)
• Adjust to reflect percent of county in
  conventional tillage (CTIC)
• Generalize texture class of each STATSGO map unit
  (fine, medium, coarse) and apply carbon
  sequestration potentials (West and Post, 2002)

• Overlay with locations of row crops

• Calculate total C sequest. by ecoregion

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Methods (Option C Riparian Ag. Afforestation)

• 55 buffer around all medium resolution NHD
  streams and waterbodies (including hydric soils /
  wetlands)
• Overlay with pasture/hay and row crop locations
• Apply the same carbon potentials derived for
  Option A
• Calculate total carbon within each ecoregion

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Modeling Results Total C Sequestration Potential
1.42 Tg yr-1
0.09 Tg yr-1
0.17 Tg yr-1
Note Ecoregions ordered West to East
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Modeling Results C Sequestration Potential per
Hectare
Note Ecoregions ordered West to East
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Results Option A
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Results Option B
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Results All Options1.62 Tg C yr-1
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Agricultural Land (Cropland Pasture) Defined as
Marginal Using Three Criteria
16 of state agricultural land base affected by
Option A
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Significance of modeled terrestrial C
sequestration potential for Virginia, relative to
Year 2010 emissions measures
Expressed as C, from fossil fuel combustion
projected using DOE data.
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Conclusions

• Provides a valuable tool for planning regional
  projects.
• The afforestation of marginal agricultural lands
  (Option A) has the highest maximum potential for
  carbon sequestration (5 of state CO2 emissions)
• MACP and RV have the highest potential rates of
  sequestration

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• Questions?