Monday, November 5, 2007 - 2:15 PM
105-4

Spotlighting the “O” Factor in Soil Genesis: An Expanded Biomantle Approach.

Donald Johnson, University of Illinois-Urbana-Champaign, 713 S Lynn St., Champaign, IL 61820 and Diana N. Johnson, Geosciences Consultants, 713 S. Lynn St., Champaign, IL 61820.

Jenny's 1941 landmark and gatekeeper book “The Factors of Soil Formation” extended the Dokuchaev (Russian) school of soil genetic philosophy. Organisms are billed as key factors. But, whereas the role of plants as soil formers is expansive in the Dokuchaev approach and Jenny's update, animals in both are given short shrift. In fact, Jenny's section titled “Animals” (p. 203) eliminated them completely: “Because of lack of sufficient observational data covering wide areas, the discussion of animal life is omitted in this treatise.” But much pedogenic information on animals existed in 1941, and in Dokuchaev's time as well, and far more has accumulated since. Jenny's semi-quantitative factorial approach to explain soils is now espoused in many modern soil texts and treatises, and represents an intellectual guide and paradigm for most pedologists, geologists, ecologists and others struggling with soil genesis. The resulting unfortunate minimalist attention given animals as genetic vectors, especially in soil mixing and particle sorting, has been, and is, a major shortcoming in the way we explain and understand soils. The biomantle approach, with conceptual roots linked to Charles Darwin, James Thorp, and Francis Hole, among others, aptly fills the void and gives new meaning and explanatory power to the “O” factor. Thorp formulated the biomantle concept, in a limited fashion, for the 1975 Soil Taxonomy (p. 21) based on his long career of observing soils in varied world environments. The expanded biomantle approach emphasizes wider soil biological processes, the array of which mediate and modulate the physicochemical processes that make Earth's soil and landforms unique. Key soil process elements of the approach are biomixing, biotransfers, and biosorting, mainly by animals. Particles smaller than burrow diameters are biotransferred within the biomantle, often to its upper part, and particles larger than burrow diameters accumulate as a basal stonelayer.