Soil carbon research and global environmental challenges

The role of soil organic carbon (SOC) in maintaining soil conditions and its resulting services is well established. Currently, over 1,000 articles per year are being published in peer-reviewed journals, and increasing at about 10% per year. It was not until the 1980s when the relation between soils and climate change was noted, and it was realized that soils play a key role as a sink and source of greenhouse gases (GHGs) ( Bouwman 1990, Scharpenseel, Ayoub and Schomaker 1990, Jenny 1980). A large number of research projects have been initiated globally in which soil C is a key component, and there have been some excellent reviews ( Lal 2004, Stockmann et al. 2013, Melillo et al. 2011). Yet, there is a lack of focus in soil C research in relation to current environmental challenges. Here we recommend research priorities to advance the knowledge base and use of soil C in relation to global human and environmental challenges: food and fiber production, water scarcity and purification, energy production, climate change, biodiversity, recycling waste, and environmental degradation. We have listed the priorities under three themes: (i) Soil C in space and time, (ii) Soil C properties and processes, and (ii) Soil C depletion and management.