Glob. Change Biol. http://doi.org/bjnm (2016)

Credit: © GUI00878 / E+ / GETTY

Methods to store organic matter in soils are increasingly being investigated as part of the climate change mitigation arsenal. Conventional studies in arable soils have tended to focus on the regularly ploughed top soil layer.

Viridiana Alcántara from the Thünen Institute of Climate-Smart Agriculture, Germany and co-workers are interested in the potential of subsoils as carbon stores as they have generally low soil organic carbon (SOC) concentrations and thus high storage potential. To address this question Alcántara et al. study storage and the stability of SOC in topsoils buried by deep ploughing (55–90 cm), translocating SOC formed near the surface into the subsoil and SOC-poor subsoil material into the 'new' topsoil.

Compared with adjacent control plots deep-ploughed soils contained on average 42 ± 13% more SOC in the total soil profile 45 years after ploughing. However, the new topsoil was still SOC depleted by 15% suggesting long-term SOC accumulation potential in the topsoil. These findings indicate that deep ploughing can contribute to SOC sequestration by enlarging the available SOC storage space.