A FUNCTIONAL-ANALYSIS OF SOIL TAXONOMY IN RELATION TO EXPERT-SYSTEM TECHNIQUES

The characteristics of Soil Taxonomy are analyzed relative to various techniques for developing expert systems. Special emphasis is placed o n computer program features that allow for more consistent application of classification systems and make them more user-friendly and unders tandable. We studied the functional logic and query processes employed by Soil Taxonomy to identify soil individuals and compared the method s with those used in other natural object classification systems. Nume rical and classical identification methods and program features found in recent computer programs were evaluated for use with Soil Taxonomy. The keys in Soil Taxonomy are purely phenetic in nature and single-ac cess in approach. In the absence of rule- and value confidence-weighti ng factors, the rules must be encoded without sequence modification to preserve the decision logic. Decisions in Soil Taxonomy query a large , often incomplete, and sometimes faulty data set, requiring error-che cking of data and the addition of expert rules to the encoded decision s to prevent indecision. Soil Taxonomy rules check within the soil ind ividual for the presence or absence of spatial and nonspatial differen tiae, specific property values, or other qualifications. Soil Taxonomy is suitable as the subject of an object-oriented expert system, and p lanning has begun on development of an automated prototype fbr the His tosol, Andisol, Spodosol, and Oxisol soil orders. Expert system featur es coupled with additional models and algorithms can be used to improv e the use and user-friendliness of Soil Taxonomy.