Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help
 

GeoTreesearch


Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

(198 KB bytes)

Title: Calibrating soil respiration measures with a dynamic flux apparatus using artificial soil media of varying porosity

Author: Butnor, John R.; Johnsen, Kurt H.

Date: 2004

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.

Publication Notes:

  • 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 pubrequest@fs.fed.us to request a hard copy of this publication. (Please specify exactly which publication you are requesting and your mailing address.)

XML: View XML

Citation:


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 Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.