Using Soil Survey to Assess and Predict Soil Condition and Change.

Soil survey organizes the landscape into units with common soil properties, characteristics and classification.  Soil survey units can be used to predict soil behavior and thus are useful for making management decisions and evaluating soil change. Traditionally, in the U.S., soil survey mapping concepts have been developed with the dominant use of the landscape in mind.  Current enhancement of soil survey includes documenting dynamic soil properties and soil change due to ecosystem management. Ecological sites are a concept used to describe ‘kinds of land’ that have common potential kinds and amounts of vegetation and characteristic response to disturbance.  In intensively managed (agronomic) systems, high inputs (e.g. energy, fertilizer, irrigation water) can confound and homogenize vegetation indicators.  In these situations, ecological site concepts, as constructed through state and transition models, can be differentiated based upon the ranges of soil function (indicated by dynamic soil properties) that occur as a result of the management (disturbance).  Groupings and interpretations of soil properties using an ecological site framework can serve as a useful tool for soil resource management and assessment and bring whole ecosystem insight into management decisions.  Such organizational frameworks should provide information about both reference conditions and alternative management systems of soil functions or dynamic soil properties within an ecological site. Reference conditions might reflect either native or naturalized vegetation or the highest possible function that an ecological site could support. The organization framework should also include information about expected soil functions or dynamic soil properties under various types of management systems that might be used.  Once established, such a framework will allow for documentation of soil change, as well as assessments of soil health and function for individual sites, which can then be extrapolated to fields and landscapes using soil survey information.