Resolving the integral connection between pedogenesis and landscape evolution

Soil is central in the terrestrial ecosystem, linking and providing feedback responses to the other components, i.e., water, atmosphere, and vegetation. However, the role of soil in landscape evolution is usually not well acknowledged. In modeling landscape evolution, soil is only treated as a residue of weathering that is transported and redistributed along the hillslope. Weathering is considered as a process that produces clays and generates unconsolidated materials available for erosion. While pedology has been debating the form of qualitative factorial models for 75 years; models for soil water, heat, solute, gas and chemical reactions in a profile have matured. As soils are distributed continuously in three dimensions across landscapes, the profile models need to consider lateral fluxes. This review outlines the role of soil in landscape modeling. First, we review the role of soil in the current landscape evolution models. We then review data and models on soil weathering rates and transport processes. We discuss soil profile models that simulate soil formation processes, and combined soil-landscape evolution models. Finally we discuss how the models can be tested and validated in the real world and suggest how both soil scientists and landscape modelers can work together to address the grand challenges in modeling earth surface processes.