Predicting Spatial Distribution of Argilic Horizon Using Auxilary Information in Regional Scale

Abstract

For supporting better soil management, the spatial distribution of soils having argilic hori=on (argilic soils) must be recognized and it can be delineate in soil survey mapping activity, but this activity consumes much time and money. This study aimed to build a decision tree model for predicting the spatial distribution of argillic hori=on based on auxiliary information using 3 predicting environmental variables; namely, geomorphic sUrface or substrate, landsurjace unit, and ecoregion beh. Three-based modeling technique was used to generate classification tree model from 318 pedon of Lampung Province, Indonesia. Argillic horizon is predicted to present in hot belt (elevation of 0-200 m above sea level) on interfluve-seepage slope with probability 84% for acid igneous rock, 83% for basic igneous rock, and 90% for acid sedimentary rock. Argillic horizon is also predicted to present in hot belt on transportational midslope with the probability 65% for transported acid sedimentary rock. Argillic horizon is predicted absent with the probability to occur ranging from 0% to 32% on otlrer combinations of landsurface unit, ecoregion belt, and substrate.