『Abstract
Pedogenesis models should give us answers to: how does soil form,
how does it evolve, where does it come from and how long does
it take to reach this state? This paper reviews quantitative models
that describe pedogenesis ab initio and the processes that directly
lead to development or evolution of soil. We review factorial,
energy, and mass-balance models. An early conceptual model comes
from James Hutton. The factorial model of Jenny provides the first
definition of soil system and quantitative approach in pedology.
Much works in pedology were devoted to proposing variations of
the factorial model in a qualitative way, such as the pathways,
and energy models. The energy model of Volubuyev attempts to calculate
the energy of soil formation at a macro-scale and the entropy
of soil at the profile scale. The energy model is used mainly
as description of the state of a soil. From conceptual, empirical
models, a move towards mechanistic models of soil formation followed
t a slower pace. The landscape model from geomorphology has made
lots of progress in quantifying and modelling soil weathering
and distribution in the landscape. These models usually consider
physical weathering and treat the soil as a single layer of regolith.
Meanwhile mechanistic pedology models consider weathering in a
profile scale at a nearly level landscape. Approach to combine
these two approaches has recently been proposed. We demonstrate
that a rudimentary mass-balance model can simulate soil thickness
and organic carbon content variation in the landscape. A soil
profile can be created by applying fundamental physical and chemical
processes. The mass-balance model provides a valuable platform
to model soil and link pedology to other modern earth science
disciplines. We discuss some criteria for pedogenesis models and
possible integration of the factorial, energy, and mass-balance
models.
Keywords: Soil genesis; Pedological modelling; Soil formation;
Landscape evolution; Non-linear dynamic systems』
Contents
1. Introduction
2. The early days
3. The pedogenesis model triad
4. The energy model
4.1. Energy of soil formation
4.2. Thermodynamics and entropy
5. Soil mass-balance models
5.1. Landscape evolution models
5.2. Weathering functions
5.3. Chemical weathering and mass-balance accounting
5.4. Soil transport models
5.5. Biological processes
5.7. Profile scale model
5.8. A soil profile model
6. Discussions and conclusions
Acknowledgements
References