The value of controlled experiments in studying soil-forming processes: A review

Experimental pedology, defined as the use of laboratory and field experiments to test hypotheses regarding pedogenic processes, was popularized in the 1950s and 1960s. Since that time there have been a number of controlled experiments that offer great promise in elucidating pedogenic processes. In this paper, we provide examples of controlled experiments that range in scale from laboratory batch studies (microcosms) to field mesocosms to whole-watershed manipulations and show how they have elucidated each of 17 elementary soil-forming processes. The experimental approach to pedology has many advantages, including the support of observational evidence, the establishment of causal rather than simply correlative relations, the linking of basic and applied pedology, and the enhancement of multidisciplinary research in studying earth's dynamic systems. (C) 2009 Elsevier B.V. All rights reserved.