US Soil Survey at Multiple Spatial, Temporal, and Organizational Scales.

County by county, national park and forest by national park and forest, soil scientists have mapped the nation in conjunction with big-picture thinkers like Marbut and Guy Smith who organized data and developed classification concepts. This bottom-up, top-down method used by the US Soil Survey since the 1890s has generated an inventory that spans spatial scales from clay mineral d-spacings to global soil orders and temporal scales from daily fluctuations of soil temperature to millions of years needed to form petrocalcic horizons on ancient landforms like the Llano Estacado. At the organizational scale, feedbacks exist among individual soil scientists, the soil science community, other scientists (e.g., agronomists, ecologists, geologists), and the general population of the United States and the world. Understanding the feedbacks between human populations, ecosystems, and the biosphere will be important for keeping the Soil Survey relevant for current and future environmental and agricultural advances.