Anthropedogenic Soil Properties After 50 Years of Agriculture.

Despite a whole body of scientific research that shows that soils change on relatively short time scales under different management regimes, classical pedological theory states that we should expect these changes to occur only in the surface few centimeters and that they are not of adequate magnitude to suggest fundamental changes in pedon character over short periods of time. Nevertheless, by resampling sites that were initially described by the National Cooperative Soil Survey between 1943 and 1963, we find fundamental changes—often to more than 100 cm depth in one or more of the following—soil color, texture, structure, depth to carbonates, depth to redoximorphic features, bulk density, organic matter content, and pH.  By synthesizing the changes in soil properties that we detected from 50 years of agricultural land use in Iowa, we develop a model of anthropedogenesis.  It states that the intensity of inputs is proportional to the intensity of impacts, and that anthropedogenesis accelerates melanization, erosion, cumulization, oxidation and braunification, while also dissolving and translocating carbonates and organic matter and altering soil structure.