Soil Drainage Class Influences on Soil Carbon in a New England Forested Watershed
2013
Raymond, Jay E. | Fernandez, Ivan J. | Ohno, Tsutomu | Simon, Kevin
Imperfectly drained soils under forests can occupy extensive areas of the landscape and understanding how they might differ from upland forest soils can be critical for understanding soil organic carbon (SOC) across forested landscapes. Research on forest SOC across drainage gradients has been limited. This research was a case study at the Bear Brook Watershed in Maine (BBWM), a long-term ecological research site, that focused on SOC pools and fluxes across three soil drainage classes (moderately well drained-MWD, somewhat poorly drained-SWPD, poorly drained-PD) and two forest types (coniferous-CF, broadleaved deciduous-BLD). Soil respiration (RS), soil temperature, soil moisture content, and extractable soluble C were measured from May through November to assess Rₛ as an indicator of biological activity. The MWD mineral soil had significantly higher C concentrations(0.71 g kg⁻¹) compared to SWPD (0.30 g kg⁻¹) and PD (0.34 g kg⁻¹). The MWD soils in CF had significantly greater C content (433.3 Mg C ha⁻¹) compared to SWPD (113.95 Mg C ha⁻¹) and PD (103.3 Mg C ha⁻¹). Soil C concentration and content was not significantly different between SWPD and PD soils. Mean mineral soil C fraction concentrations (active, stable, passive) expressed as a percent of the total soil mass were significantly different among soil drainage classes. Results from this case study suggest that pedogenesis, above and belowground plant productivity, and moisture availability across the growing season play important roles in determining SOC dynamics in these forests.
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