Soils and Carbon Storage

Soils act as both sources and sinks of atmospheric C and as such there is great interest in investigating the impact of land use and land use change on C stocks in soils. Peatlands occupy ~20% of the irish landscape and store 75% of all C stocks. While pristine peatlands are long term C sinks, drainage and land use may change these systems to sources of soil C. Forests are generally recognised to be C sinks although the role of soil differs between soil types. Studies to date suggest that afforested Gley soils are C sinks while afforested Brown Earths may lose C. Grassland is the dominant land use and site based studies suggest that it could be a C sink of 0.5 t C ha−1 year−1. Cropland is a net C source with cultivation being the principal driver of this loss. Options to maintain or enhance C stocks in tillage systems include the use of cover crops, straw and manure incorporation and a move to minimum tillage. Despite the progress that has been made in quantifying C stocks in Irish soils and in understanding the impact of land use on soil C stocks many information gaps remain.