QUANTIFYING AND EXTRAPOLATING SOIL INORGANIC CARBON ACROSS SOILS OF THE WESTERN SNAKE RIVER PLAIN, IDAHO, USING PRESSURIZED CALCIMETRY
Preliminary findings along the Gowen terrace in Boise, ID, (K-Ar age of 0.527 +/- 0.210 Ma), show that active K horizons form at a depth of approximately 90 centimeters underlain by repeating K horizons indicating a sequence of buried soils (Othberg, 1994). The total SIC content for soils on this terrace is 1.4%. Based off this SIC content, the extrapolated mass of carbon per unit area in the Gowen terrace soils is 36 MT/ha. Compared to results from a similar site in Kuna Butte, ID soil organic carbon (SOC) ranged from 22 to 46 MT/ha (Austreng, 2012). This comparison shows that SIC is a significant component of total soil carbon storage.
These results show that there is a significant amount of carbon storage in the form of pedogenic carbonate. A more accurate estimate of total SIC in the WSRP will be gained pending more results from a diverse set of soils with different ages, parent materials, and geomorphic settings. This study will build a framework for understanding levels of SIC storage based on age and other soil forming factors within the WSRP and could prove useful in the preservation of this reservoir.