Modelling long-term in situ soil profile evolution: application to the genesis of soil profiles containing stone layers

摘要

Models of soil genesis are potentially of great importance in assessing the effects of global change on ecosystems, and may also contribute to our understanding of soil genetic processes. Many quantitative models have so far focused on individual soil genetic processes and are difficult to extrapolate to the landscape scale. A few attempts have been made to model soil evolution as a whole from a pedologic perspective. This study develops a quantitative model of soil formation at the profile scale, taking into account major soil-forming processes. These include physical and chemical weathering of primary minerals, strain processes, and bioturbation. The model allows the quantification of the evolution of the particle size, mineral composition and bulk density of the soil. The model is applied with varying values of input parameters, and is compared with actual soil genetic processes. Running the model results in the formation of stone-layered soil profiles. Stone-line formation by means of bioturbation, as already described in the literature, seems to be adequately simulated. Planned improvements of the model include implementation of other major soil genetic processes such as leaching, organic matter influence, etc. This model will then have to be implemented spatially considering particularly redistribution processes, to reproduce soil formation at the landscape scale.