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Abstract
In times of accelerated climate change, both natural and man-made landscapes experience
changes in the turnover of soil organic matter. Especially on ecosystems with low levels of
plant available nutrients and low turnover times (Leifeld, 2005). Since 1999, the VOLCAN
project has been set up in order to manipulate different climate scenarios. These scenarios
have been deduced from predictions made by the intergovernmental panel on climate
change (IPCC). Changes concerning a global net temperature increase in combination with
extended levels of summer drought. Former research has been implemented on carbon
dynamics at the phosphorus (P) deficient Dutch heathland ‘Oldebroekse heide’. Climate
changes caused effects in plant biomass, annual litter production and in litter decomposition
rates (Van Meeteren et al., 2005). The aim of this study is to measure, model and predict the
changes in the carbon (C) dynamics in the topsoil. But in contrast to the research of Van
Meeteren (2005) the focus will be on the description and modeling of the vertical
differences in the topsoil. The nuanciation might be that the input of labile soil organic
matter (SOC) will only affect the carbon turnover in the upper layer of the topsoil. While the
more recalcitrant SOC in the lower layers might have a different response to either global
warming or repeated summer droughts. By dividing the organic topsoil into three different
layers and subsequently measuring the daily respiration per amount of carbon in the soil.
The verdict might be that the depth of the SOM has major effects on the net CO2 production
of the organic topsoil as a whole. Since Knorr et al., (2005) stated that the apparent lack of
temperature dependence could be an artefact due to neglecting the extreme heterogeneity
of soil carbon. Examining the topsoil on a vertical scale, will reduce the heterogeneity of
each layer drastically. Layering the topsoil will make it possible to look at differences
between labile and non-labile soil organic carbon (SOC). And since evidence has been
presented that non-labile SOC is more sensitive to global warming (Knorr et al., 2005) this
research might have an interesting view on the future of the Dutch heathland.