Pacific Northwest Research Station

Title: Soil carbon changes: comparing flux monitoring and mass balance in a box lysimeter experiment.

Author: Nay, S.M.; Bormann, B.T.

Date: 2000

Source: Soil Science Society of America Journal. 64(3): 943-948

Description: Direct measures of soil-surface respiration are needed to evaluate belowground biological processes, forest productivity, and ecosystem responses to global change. Although infra-red gas analyzer {IRGA) methods track reference CO₂ flows in lab studies, questions remain for extrapolating IRGA methods to field conditions. We constructed 10 box lysimeters with homogenized mixtures of sandy loam and cattle manure and kept them free of plants to create a range of CO₂ fluxes. Infra-red gas analyzer measurements, applied biweekly, were then compared to mass baiance—based measures of changes in soil C over 8 mo. The CO₂ fluxes measured with IRGA were not significantly different (P < 0.05) from the mass balance measure in 9 of the 10 boxes. The only statistically significant difference was in the lysimeter with the highest initial C content; this box had elevated soil temperatures early in the trial, suggesting a composting effect that may have interfered with IRGA measures. Variations in the mass balance estimates were higher than expected, demonstrating how difficult establishing a true reference in field studies is. We conclude that fluxes of CO₂ from soils can be monitored with an IRGA-based chamber system in the field to produce reliable estimates of cumulative C loss. Such field measures will likely be much more variable than laboratory measures, however, and thus will require extensive sampling.

Keywords: 

View and Print this Publication (867 KB)

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.

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

Citation

Nay, S.M.; Bormann, B.T.  2000.  Soil carbon changes: comparing flux monitoring and mass balance in a box lysimeter experiment..   Soil Science Society of America Journal. 64(3): 943-948