Bedrock, Regolith, and Soil Continuum: Pedogenic Perspectives and Factors Controlling Spatial Distribution of Soils in the Critical Zone

Chapter 6 introduces soils, one of the basic components of the Critical Zone. Here, we describe the main soil-forming mechanisms and various terms applied to soil components and the parent materials that form soils. Descriptions of soil forming models are complemented by approaches to studying soils practically and effectively in the field, and some methods used to measure and quantify soil characteristics and processes are introduced. The dimensionless mass transfer coefficient tau is discussed in detail as one approach to interpret biogeochemical profiles in soils. The chapter concludes with two case studies that apply soil forming frameworks and soil profile data to understand drivers of soil formation as a function of climate and time, respectively.