The Use of Computer-Assisted Mapping Techniques to Delineate Potential Areas of Salinity Development in soils: II. Field Verification of the Threshold Model Approach

Abstract

A study area within the Wellton-Mohawk Irrigation District, which lies east of Yuma, Arizona, was used to verify the threshold model proposed in Part I. Verification results showed that the threshold model could not reliably predict salinization potential; consequently, a modified threshold model, Model 1, was formulated. Model 1 was capable of predicting nearly 60 percent of the salinization potentials correctly, a significant improvement over the original threshold model. Nevertheless, Model 1 fell short of being considered a reliable forecasting tool. It is postulated that the interactions between the factors believed to give rise to salinity development at the study site were too complex to characterize with the simple threshold model approach. Rather, a means of weighting the significance of the individual factors in the overall salinization process may be necessary.