Soil Attribute Prediction Using Terrain Analysis

Abstract

Abstract This study is based on the hypothesis that catenary soil development occurs in many landscapes in response to the way water moves through and over the landscape. Furthermore, terrain attributes can characterize these flow paths and, therefore, soil attributes. Significant correlations between quantified terrain attributes and measured soil attributes were found on a 5.4‐ha toposequence in Colorado. Slope and wetness index were the terrain attributes most highly correlated with surface soil attributes measured at 231 locations on a 15.24‐m grid. Individually, they accounted for about one‐half of the variability in A horizon thickness, organic matter content, pH, extractable P, and silt and sand contents. This represents an incorporation of finer scale process‐based information relating to soil formation patterns in the landscape. The computed and measured ranges of terrain and soil attributes, respectively, can be used to enhance an existing soil map, even when the exact form of the relationship is unknown. As a first approximation, a linear relationship was assumed and the interpolated predictions of A horizon thickness and pH compared reasonably well with the observed. Such techniques may also be applied as a first step in unmapped areas to guide soil sampling and model development.