REGIONAL ESTIMATES OF CARBON SEQUESTRATION POTENTIAL - LINKING THE ROTHAMSTED-CARBON-MODEL TO GIS DATABASES

Soil organic matter (SOM) represents a major pool of carbon within the biosphere. It is estimated at about 1400 Pg globally, which is roughl y twice that in atmospheric CO2. The soil can act as both a source and a sink for carbon and nutrients, Changes in agricultural land use and climate can lead to changes in the amount of carbon held in soils, th us, affecting the fluxes of CO2 to and from the atmosphere. Some agric ultural management practices will lead to a net sequestration of carbo n in the soil. Regional estimates of the carbon sequestration potentia l of these practices are crucial if policy makers are to plan future l and uses to reduce national CO, emissions. In Europe, carbon sequestra tion potential has previously been estimated using data from the Globa l Change and Terrestrial Ecosystems Soil Organic Matter Network (GCTE SOMNET). Linear relationships between management practices and yearly changes in soil organic carbon were developed and used to estimate cha nges in the total carbon stock of European soils. To refine these semi -quantitative estimates, the local soil type, meteorological condition s and land use must also be taken into account. To this end, we have m odified the Rothamsted Carbon Model, so that it can be used in a predi ctive manner. with SOMNET data. The data is then adjusted for local co nditions using Geographical Information Systems databases. In this pap er, we describe how these developments call be used to estimate carbon sequestration at the regional level using a dynamic simulation model linked to spatially explicit data. Some calculations of the potential effects of afforestation on soil carbon stocks in Central Hungary prov ide a simple example of the system in use.