Modeling soil-landscape and ecosystem properties using terrain attributes

Soil-landscape patterns result from the integration of short- and long-term pedogeomorphic processes. A 2-ha hillslope catena in California shows short-distance variation in A horizon depth from 8 to 80 cm and in soil depth from 8 to >450 cm in convex to concave positions. Similar variations in net primary productivity (NPP) and soil C represent significant information often not captured by soil survey maps. Strong correlations between these measured soil-landscape variables and explanatory digital terrain attributes are used to develop quantitative soil-landscape models. We were able to account for between 52 and 88% of soil property variance using easily computed terrain variables such as slope and flow accumulation. Spatial implementation of the models suggest lateral redistribution processes resulting in differential accumulation of C and soil mass in convergent and divergent landscape positions. The models are explicit and quantitative, which enables their use for testing hypotheses about the spatial distribution of fine-scale landscape and ecosystem processes and for parameterizing spatially distributed hydrological and ecosystem simulation models.