Chapter

North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes

Volume 166 of the series Ecological Studies pp 163-189

Soil Respiration and Litter Decomposition

  • Paul J. Hanson
  • , Elizabeth G. O’Neill
  • , M. Lala S. Chambers
  • , Jeffery S. Riggs
  • , J. Devereux Joslin
  • , Mark H. Wolfe

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Abstract

Emissions of CO2 from the organic and mineral soil horizons into the atmosphere are considered a good representation of soil respiration (R soil) when the diffusion-driven losses to the atmosphere are at equilibrium with the biological rates of CO2 production (Hanson et al. 2000). R soil is the net effect of the biological activity of autotrophic roots and associated rhizosphere organisms plus the mineral soil heterotrophic activity of bacteria, fungi, and soil fauna. Whereas the activity of soil heterotrophic organisms is proportionate to the decomposition of soil carbon, CO2 lost from root and rhizosphere activity is a function of the consumption of organic compounds supplied by aboveground organs of plants (Horwath et al. 1994). Notwithstanding the complex nature of the sources of CO2 contributing to it, R soil represents a good measure of the collective response of root and soil biological activity to environmental conditions (Edwards et al. 1970; Hanson et al. 2000). Because soil respiration is a very large fraction of gross primary productivity (Curtis et al., 2002), its quantification must be a high priority in any attempt to establish carbon budgets for ecosystems (see Chapter 22, this volume).