FUZZY-LOGIC AND RISK-BASED SOIL INTERPRETATIONS

Fuzzy set logic is used to express the risk in soil interpretation rat ings. Uncertainty inherent in the definition of estimated sets of prop erties used to characterize a given map unit is described with the hel p of fuzzy sets. Threshold levels of soil properties (where no adverse consequences can be expected) are used to formulate a continuum for a ssessment. Different types of adverse consequences may be considered. Here we describe economic, noneconomic private, and non-economic socia l consequences. The relative consequences are functions of the deviati on between the estimated and threshold soil properties characterizing a given rating. We assumed that the consequence functions estimated by an expert group are exact. The methodology can be extended to uncerta in consequence functions and is applied to soil suitability ratings in four map units in Saunders County, Nebraska. The integrated risk inde x calculated with the methodology can help to select a cost-effective solution to management considerations.