Submitted to: Biogeosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2011
Publication Date: 12/2/2011
Citation: Moyano, F., Bouckaert, L., Cook, F., Orchard, V., Craine, J., Yuste, J.C., Axel, D., Epron, D., Formanek, P., Franzluebbers, A.J., Llstedt, U., Katterer, T., Reichstein, M., Simo, A.R., Ruamps, L., Thomsen, I., Chenu, C., Vasilyeva, N., Subke, J.A. 2011. The moisture response of soil heterotrophic respiration: Interaction with soil properties. Biogeosciences. 8:11577-11599. 2011. Interpretive Summary: Prediction of carbon dioxide flux from soils (i.e. soil respiration) is important for understanding global carbon cycling, greenhouse gas emissions from natural sources, and potential impacts affecting climate. Although we know that temperature and moisture are the largest factors influencing soil respiration, experimental evidence is wide ranging in how respiration responds to moisture. A group of investigators from UMR Bioemco in France, Ghent University in Belgium, CSIRO in Australia, ESR in New Zealand, Kansas State University, CREAF in Spain, Johann Heinrich von Thuenen-Institut in Germany, UMR EEF in France, Mendel University in the Czech Republic, Swedish University of Agricultural Sciences in Sweden, Max Planck Institut fuer Biogeochemie in Germany, Estación Experimental de Zonas Áridas in Spain, Aarhus University in Denmark, University of Stirling in Scotland, and USDA Agricultural Research Service in Watkinsville Georgia collaborated on a project to assess soil respiration in response to moisture variations from 90 soils at 42 sites from around the world. Soil respiration was generally responsive to soil moisture variations in a coherent manner in all soils, but there were subtle differences due to unique soil physical properties that resulted in concerns when soil respiration was modeled on a regional-level scale in England and Wales. This integrated analysis of diverse soils will help to improve process-based soil carbon models for use by scientists around the world to predict the effects of climate change on future greenhouse gas emissions.
Technical Abstract: Soil moisture-respiration functions are used to simulate the various mechanisms determining the relations between soil moisture content and carbon mineralization. Soil models used in the simulation of global carbon fluxes often apply simplified functions assumed to represent an average moisture-respiration response across soils. The limited empirical support for such functions and the large observed variation of the moisture-respiration relation between models and across soils implies an associated uncertainty introduced in carbon flux predictions. Improving the representation of soil moisture effects on microbial activity and reducing such uncertainties has been recognized as an essential step in obtaining meaningful predictions of future soil carbon stocks. We present here a data-driven analysis of the soil moisture-respiration relation, carried out using commonly used measures of soil moisture and showing a consistent dependence on changing soil physical conditions. Soil properties and their interaction with soil moisture were found to influence the response of heterotrophic soil respiration to moisture. Our analysis of 42 different soils around the world suggests a strong soil respiration-moisture relationship, but with unique variations depending upon soil physical properties. This analysis should help to improve process-based soil carbon models.