Issues and pressures facing the future of soil carbon stocks with particular emphasis on Scottish soils

Soil organic carbon (C) plays a critical role in supporting the productive capacity of soils and their ability to provide a wide range of ecologically important functions including the storage of atmospherically derived carbon dioxide (CO2). The present paper collates available information on Scottish soil C stocks and C losses and reviews the potential pressures on terrestrial C, which may threaten future C stocks. Past, present and possible future land use, land management practices and land use changes (LUCs) including forestry, agriculture, nitrogen (N) additions, elevated CO2 and climate change for Scotland are discussed and evaluated in relation to the anthropogenic pressures on soil C. The review deduces that current available data show little suggestion of significant changes in C stocks of Scottish soils, although this may be due to a lack of long-term trend data. However, it can be concluded that there are many pressures, such as climate change, intensity of land use practices, scale of LUC, soil erosion and pollution, which may pose significant threats to the future of Scottish soil C if these factors are not taken into consideration in future land management decisions. In particular, this is due to the land area covered by vulnerable peats and highly organic soils in Scotland compared with other areas in the UK. It is therefore imperative that soil C stocks for different land use, management practices and LUCs are monitored in more detail to provide further insight into the potential changes in sequestered C and subsequent greenhouse gas emissions, as advised by the United Nations Framework Convention on Climate Change (UNFCCC).