Friday, October 3, 2008: 4:20 p.m.
Douglas B. Yager
,
Minerals Team, USGS, Denver, CO
Alison Burchell
,
Natural Capitalism Solutions, Boulder, CO
Rob Robinson
,
Bureau of Land Management, ret.
Richard P. Dick
,
The School of Environment and Natural Resources, Ohio State University, Columbus, OH
Jack Hidinger
,
State Partnerships and Sustainable Practices, US EP, Denver, CO
Stephanie Odell
,
San Juan Public Lands Center, US Bureau of Land Management, Durango, CO
Soils represent a potentially large
and important natural carbon reservoir. The Natural
Terrestrial Sequestration potential (NTS) of soils is among the “CO2 stabilization wedges'
or carbon management strategies needed to thwart doubling of atmospheric CO2.
To better understand NTS, we analyzed
soil-cores from 16 Colorado,
Rocky Mountain Cordillera sites. Northerly-facing, high-plains to alpine sites
in non-wetland environments were selected, because such temperate soils may be
less susceptible to baseline C-pool declines due to global warming than soils
in warmer regions. All undisturbed soils sampled have 2 to 6 times greater total
organic soil carbon (TOSC) than global TOSC averages (4 – 5 Wt. %). Forest soils derived from weathering of intermediate to
mafic volcanic bedrock have the highest C
(34.16 Wt %), C:N (43),
microbial-biomass arylsulfatase (ave.
142, high 338). Intermediate TOSC was identified
in soils derived from Cretaceous shale (7.2 Wt. %) and Precambrian, felsic
gneiss (6.2 Wt. %). Unreclaimed mine-sites have the lowest: C (0.01 to 0.78 Wt. %), C:N (2.4 to 6.5), and arylsulfatase (0
to 41). However, reclaimed and undisturbed
mined-lands soils derived from propylitically-altered andesite have high: C (13.5 – 25.6 Wt. %), C:N (27), arylysulfatase (338). In our previous studies, propylitic-rocks
were found to have high Acid Neutralizing
Capacity (ANC). Radiocarbon dates on charcoal collected from paleo-burn
horizons (found in high C, N soils) indicates an old carbon pool (840-5,440 ±40
yrs B.P).
The data suggest volcanic-soils, including
volcanic-hosted reclamation sites, represent a potentially significant C-sink. Future
research will probe: ecosystem variability; NTS in pilot-projects that model natural
“geomimicry” processes and use soil-amendments (e.g.: ANC-rock; biochar) to support
soil-productivity, soil-moisture and CO2-sequestration (mine-reclamation,
forest-health, watershed-protection); implications for disturbing soils that
sequester C for millennia; the geo-environmental value of NTS as carbon markets
mature and offer economic measures to areas targeted for resource extraction;
and post-reclamation success.
