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This article in SSSAJ

  1. Vol. 77 No. 3, p. 699-708
     
    Received: Oct 16, 2012
    Published: April 30, 2013


    * Corresponding author(s): chance@forerunnerresearch.ca
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doi:10.2136/sssaj2012.0352

Quantifying Lateral Diffusion Error in Soil Carbon Dioxide Respiration Estimates using Numerical Modeling

  1. Chance Creelmana,
  2. Nick Nickersonb and
  3. David Riskc
  1. a Environmental Sciences Research Centre, St. Francis Xavier University Antigonish NS, Canada B2G 2W5 and Forerunner Research Inc. Dartmouth NS, Canada B2Y 4M9
    b Environmental Sciences Research Centre St. Francis Xavier University Antigonish NS, Canada B2G 2W5 and, Department of Earth Sciences Dalhousie University Halifax NS, Canada B3H
    c Environmental Sciences Research Centre St. Francis Xavier University Antigonish NS, Canada B2G 2W5

Abstract

A variety of chamber methodologies have been developed in an attempt to accurately measure the rate of soil CO2 respiration. However, the degree to which these methods perturb and misread the soil signal is poorly understood. One source of error in particular is the introduction of lateral diffusion due to the disturbance of the steady-state CO2 concentrations. The addition of soil collars to the chamber system attempts to address this perturbation, but may induce additional errors from the increased disturbance. Using a numerical three-dimensional (3D) soil-atmosphere diffusion model, we have undertaken a comprehensive and comparative study of existing static and dynamic chambers. Specifically, we are examining the 3D diffusion errors associated with each method and opportunities for correction. The impacts of collar length and diffusion parameters on lateral diffusion around the instruments are quantified to provide insight into obtaining more accurate soil respiration estimates. Results suggest that while each method can approximate the true flux in low diffusivity environments, the associated errors can be large and vary substantially in their sensitivity to both method-specific and environmental parameters. In some cases, factors such as collar length and soil diffusivity are coupled in their effects on accuracy.

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Copyright © 2013. Copyright © by the Soil Science Society of America, Inc.