Long-term increases in soil carbon due to ecosystem fertilization by atmospheric nitrogen deposition demonstrated by regional-scale modelling and observations

• Published in: Scientific reports 2017-05, Vol.7 (1), p.1890-11, Article 1890
• Main Authors: Tipping, E., Davies, J. A. C., Henrys, P. A., Kirk, G. J. D., Lilly, A., Dragosits, U., Carnell, E. J., Dore, A. J., Sutton, M. A., Tomlinson, S. J.
• Format: Article
• Language: English
• Subjects: 704/47/4112; 704/47/4113; Anthropogenic factors; Carbon; Carbon dioxide; Carbon dioxide removal; Ecosystem models; Ecosystems; Fertilization; Humanities and Social Sciences; multidisciplinary; Nitrogen; Organic carbon; Organic soils; Phosphorus; Primary production; Science; Science (multidisciplinary); Soils; Topsoil; Turnover time
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-02002-w

Fertilization of nitrogen (N)-limited ecosystems by anthropogenic atmospheric nitrogen deposition (N dep ) may promote CO 2 removal from the atmosphere, thereby buffering human effects on global radiative forcing. We used the biogeochemical ecosystem model N14CP, which considers interactions among C (carbon), N and P (phosphorus), driven by a new reconstruction of historical N dep , to assess the responses of soil organic carbon (SOC) stocks in British semi-natural landscapes to anthropogenic change. We calculate that increased net primary production due to N dep has enhanced detrital inputs of C to soils, causing an average increase of 1.2 kgCm −2 (c. 10%) in soil SOC over the period 1750–2010. The simulation results are consistent with observed changes in topsoil SOC concentration in the late 20 th Century, derived from sample-resample measurements at nearly 2000 field sites. More than half (57%) of the additional topsoil SOC is predicted to have a short turnover time (c. 20 years), and will therefore be sensitive to future changes in N dep . The results are the first to validate model predictions of N dep effects against observations of SOC at a regional field scale. They demonstrate the importance of long-term macronutrient interactions and the transitory nature of soil responses in the terrestrial C cycle.