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There is an ever increasing need to make pedology a process-oriented and quantitative scientific discipline. Key tools in this effort are tracers that help quantify the direction and rates of various pedogenic processes over timescales beyond the reach of field studies. Though not commonly acknowledged, several atmospheric pollutants could be ideal tracers for studying soil forming processes and their rates. This review, among many potential pollutants, focuses on lead (Pb) and spheroidal carbonaceous particles (SCPs) entering the soil through atmosplleric inputs. These contaminants enter soils at their surface, where mass fluxes through accumulation, erosion, mixing, and translocation are most vigorous. The rationale for expecting these atmospheric contaminants to be suitable as tracers are; (1) the atmospherically derived fractions can be distinguished within the complex soil matrix, (2) the boundary condition for their inputs to the soil can be well constrained in time and space, and (3) their biogeochemical properties make them suitable proxies for the movement of various solid components in soils. By adapting the pollutants to Simonson's conceptual view of soil formation within a mathematical framework we demonstrate how the vertical distribution of the atmospheric contaminants could be used to infer the mass-fluxes responsible for biogeochemical evolution of soils. Although there could be problems in applying the methods outlined in this paper for weakly contaminated soils with a strong geogenic lead source, the potential for using the methods for soils formed in industrialized urban areas is high. [ABSTRACT FROM AUTHOR]

Virtually all soil chronosequence studies have equated the degree of mineral weathering with the soil age, which is equal to the time since the cessation of erosion or deposition. The primary minerals from the parent material, however, enter the soil as the weathering front propagates downward and are depleted via chemical weathering. The residence time of minerals is thus a function of both the rate of conversion of parent material to soil (i.e., soil production) and the minerals' susceptibility to chemical weathering reactions. We find that mineral residence times are significantly shorter than the soil age. By mathematically considering the interactions among soil production and chemical weathering, we demonstrate that traditional estimates of mineral-specific chemical weathering rates from soil chronosequences may diverge by several orders of magnitude from the actual weathering rates. [ABSTRACT FROM AUTHOR]

Burrowing organisms assist in shaping earth surfaces and are simultaneously affected by the environment they inhabit; however, a conceptual framework is not yet available to describe this feedback. We introduce a model that connects the population density of soil-burrowing animals to sediment transport via energy. The model, combined with avail- able data from California hillslopes where soil erosion is driven by pocket gophers (Thomomys bottae), suggests that a gopher annually expends ∼9 kJ of energy, or ∼1% of reported burrowing energy expenditure, in generating sediment transport. The model is used to evaluate the case that gophers prefer to populate thicker soils. The results suggest that this behavior may drastically dampen the spatial and temporal variations of soil thickness and gopher populations, implying that burrowing organisms may create landscapes distinct from those affected by abiotic processes. [ABSTRACT FROM AUTHOR]