State and Transition Ecosystem Models⎯Application to Soil Survey and Dynamic Soil Properties Databases

State and transition models. Arid and semiarid rangelands are hypothesized to function as nonequilibrium systems (Westoby et al. 1989). Models that capture these nonequilibrium dynamics at the site (groups of similar soil map units; sensu, Shiflet 1973) level are called state and transition models (STMs). Although the application of STMs is at an early stage, relatively large gains in understanding rangeland function are being realized by implementing this new approach. Developing an information system to manage this knowledge will require the reinterpretation of existing data and new observations and experiments within a precisely defined structure if we are to make progress in providing better quality information for land management decisions.