Integrating Nonlinear Dynamics and Historical Field Pedology

The study of nonlinear dynamics in pedology has been dominated by analytical techniques derived largely from other fields. Ultimately, however, confronting nonlinear complexity requires problematizing from within a pedological context. This study focuses on deterministic chaos in pedogenesis. Traditional methods of chaos detection and analysis depend largely on long time and dense spatial series data only occasionally available for pedology and soil geomorphology studies, or on numerical models only indirectly relevant to field studies. However, methods exist for detecting chaos in qualitative and categorical spatial data of the type commonly produced by, or available to, pedologists. Many of these methods are similar to, or are adaptations of, familiar techniques for partitioning within- and between-unit variation, and for identifying elementary uniform landscape units. The manifestations of chaos in soil landscapes take the form of divergent vs. convergent evolution (increasing vs. decreasing irregularity), disproportionality vs. proportionality of response to perturbations or initial variations, and the (lack of) geographical consistency or commonality of response. These also serve as criteria for distinguishing between achievement of a new steady-state and unstable divergence in interpreting soil changes. Study of nonlinear dynamics in pedology need not be restricted to theoreticians and modellers, as complex nonlinear behaviors can be identified and diagnosed using the types of data, observations, and methods typically available to field-oriented soil and earth scientists. Even more important is the need to further inform the study of nonlinear dynamics on the basis of field-based pedology.