Topography and Soil Acidity in an Arctic Landscape
- David W. Valentine and
- Dan Binkley
Despite its importance in landscape biogeochemistry, the factors accounting for differences in soil pH across landscapes are not well defined. We analyzed the influence of three factors — acid quantity, degree of neutralization, and strength — on soil pH across an arctic toposequence next to the Sagavanirktok River in northern Alaska. The standard definitions of these factors in solutions cannot be applied directly to soils. Instead, we defined several operational factors deriveable from acid and base soil titrations that more appropriately define these factors for soils: acid quantity as the base-neutralizing capacity to pH 8.2, the degree of neutralization as the degree to which the acid complex was deprotonated (as determined by measured acidneutralizing capacity), and acid strength as the residual pH difference unexplained by the other two factors. The degree of neutralization (DN), like base saturation, indexes the acidic character of the exchange complex, and this factor accounted for most of the pH differences among the six ecosystems along the toposequence. This was consistent with the recognized importance of base saturation in controlling soil pH. Acid quantity and strength were also important in determining pH differences between some sites.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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