Modelling the dynamics of equatorial forest soil deep carbon in changing environments - C-PROFOR

Resumo

The Amazonian podzols may store larger amounts of carbon (C) particularly in their deep Bh horizons. Similar high C storage is likely to exist in similar climate/soil areas, mainly in Africa. Such C stocks raise the problem of their stability in response to changes in land use or climate. Any significant changes in vegetation cover would significantly alter the soil water dynamics, Which is likely to affect the organic matter (OM) turnover in soils. The direction of the change is not clear and is likely to depend on the specific conditions and properties of the soils. Considering the Bh of the equatorial podzols, it can be assumed that the drying of these generally saturated soils will lead to an increase in C mineralization, although the extent of this increase has not yet been determined. In 1hls context, the project objective is to quantify the rates of podzol OM mineralization under different scenarios of climate change towards drier or more variable moisture conditions. This requires (1) the quantification of podzol OM mineralization under alternating wet/dry cycles and (2) the modelling of water dynamics in podzols systems submitted to land use or climate changes. (1) will be addressed by quantifying the ability of soil microorganisms to metabolize the soil OM by monitoring mineralization at different matric potentials and under alternating wet/dry cycles, and {2) by modelling water dynamics under different land use/climate scenarios, using the knowledge of podzol system already obtained or being acquired by ongoing studies. Additional data and validation of the long-term modelling will be sought by studying natural chronosequences… (AU)