New A Horizon Protocols for Topsoil Characterization in Canada

A new framework for addressing topsoil characterization was developed to provide enhanced capability in A horizon lowercase suffixes for tracking changes and impacts from environmental and anthropogenic stressors especially at landscape and watershed scales. Critical to sustaining agricultural crop and forestry production, the A horizon is the first mineral horizon to respond to these stressors leading to topsoil changes in physical, chemical and biological processes and soil properties. A new system comprised of four levels of lowercase suffixes was developed as an outcome of workshops held in Canada and Germany, review by soil classification and mapping experts and field testing. The first level of new lowercase suffixes identifies genetic processes and impacts from anthropogenic/industrial activities; the second level records the kind of primary soil structure; the third level, range classes of per cent organic matter; and, the fourth level, range classes for pH (0.01 M CaCl 2). Examples of the new A horizon lowercase suffixes are shown for selected Canadian soils. The new framework will provide enhanced taxonomic protocols for topsoil characterization of A horizons when undertaking detailed monitoring and assessment studies in determining the effectiveness of remedial measures and beneficial management practices.