Wednesday, September 28, 4-5 p.m.
Boyd Science Center, Room 001
The Center for the Environment invites the campus community to attend an Environmental Science Colloquium: "Uncertainties in Detecting Decadal Change in Soil Carbon and Extractable Elements in Northern Forests," presented by Olivia Bartlett, Department of Social Science, Plymouth State University & PhD candidate, Natural Resources and Earth System Sciences, University of New Hampshire.
Northern Forest ecosystems have been or are being impacted by land use change, forest harvesting, acid deposition, atmospheric CO2 enrichment, and climate change. Each of these has the potential to modify soil forming processes, and the resulting chemical stocks. Horizontal and vertical variations in concentrations complicate determination of temporal change. This study evaluates sample design, sample size, and differences among observers as sources of uncertainty when quantifying soil temporal change over regional scales. Forty permanent monitoring plots were established on the White Mountain National Forest in central New Hampshire and western Maine. Soil pits were characterized and sampled by genetic horizon at plot center in 2001 and resampled again in 2014 two-meters on contour from the original sampling location. Laboratory analyses for both sampling years included pH in 0.01 M CaCl2 solution and extractable Ca, Mg, Na, K, Al, Mn, and P in 1 M NH4OAc solution buffered at pH 4.8. The results from this study suggest that resampling efforts within a site, repeated across a region, to quantify elemental change by genetic horizon is an appropriate method of detecting soil temporal change in this region. Sample size and design considerations from this project will have direct implications in determining the number of sites and methods of sampling for designing future monitoring programs to characterize change in soil elements.