Soil organic matter in a stressed world

Soil organic matter (SOM) is quantitatively a minor component (by mass and volume) of most soils, yet it is responsible for facilitating or moderating many key soil ecosystem services that affect agricultural food security, biodiversity and environmental quality. Its constituents range in mean residence times from 10 000 years for charcoal-like materials. It is these somewhat enigmatic aspects of SOM that not only provoke such interest from the research community, but also drive the need for applied research that enables custodians of the landscape to effectively manage SOM in a way that limits its loss and maintains or enhances its stock and function.