You are here: Home
/ Publication Information
Title: Calibrating soil respiration measures with a dynamic flux apparatus using artificial soil media of varying porosity
Author: Butnor, John R.; Johnsen, Kurt H.;
Source: European Journal of Soil Science, December 2004, 55, 639–647
Publication Series: Miscellaneous Publication
Description: Measurement of soil respiration to quantify ecosystem carbon cyclingrequires absolute, not relative, estimates of soil CO2 efflux. We describe a novel, automated efflux apparatus that can be used to test the accuracy of chamber-based soil respiration measurements by generating known CO2 fluxes. Artificial soil is supported above an air-filled footspace wherein the CO2 concentration is manipulated by mass flow controllers. The footspace is not pressurized so that the diffusion gradient between it and the air at the soil surface drives CO2 efflux. Chamber designs or measurement techniques can be affected by soil air volume, hence properties of the soil medium are critical. We characterized and utilized three artificial soils with diffusion coefficients ranging from 2.7 x 10-7 to 11.9 x 10-7 m2s-1 and porosities of 0.26 to 0.46. Soil CO2 efflux rates were measured usinga commercial dynamic closed-chamber system (Li-Cor 6400 photosynthesis system equipped with a 6400-09 soil CO2 flux chamber). On the least porous soil, small underestimates (<5%) of CO2 effluxes were observed, which increased as soil diffusivity and soil porosity increased, leadingto underestimates as high as 25%. Differential measurement bias across media types illustrates the need for testing systems on several types of soil media.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- You may send email to email@example.com to request a hard copy of this publication. (Please specify exactly
which publication you are requesting and your mailing address.)
XML: View XML
Butnor, John R.; Johnsen, Kurt H. 2004. Calibrating soil respiration measures with a dynamic flux apparatus using artificial soil media of varying porosity. European Journal of Soil Science, December 2004, 55, 639–647
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility