Construction and Testing of a Simple and Economical Soil Greenhouse Gas Automatic Sampler

ABSTRACT

Quantification of soil greenhouse gas emissions requires considerable sampling to account for spatial and/or temporal variation. With manual sampling, additional personnel are often not available to sample multiple sites within a narrow time interval. The objectives were to construct an automatic gas sampler and to compare the accuracy and precision of automatic versus manual sampling. The automatic sampler was tested with carbon dioxide (CO₂) fluxes that mimicked the range of CO₂ fluxes during a typical corn-growing season in eastern Nebraska. Gas samples were drawn from the chamber at 0, 5, and 10 min manually and with the automatic sampler. The three samples drawn with the automatic sampler were transferred to pre-vacuumed vials after 1 h; thus the samples in syringe barrels stayed connected with the increasing CO₂ concentration in the chamber. The automatic sampler sustains accuracy and precision in greenhouse gas sampling while improving time efficiency and reducing labor stress.

Keywords:

• manual sampling
• diffusion
• gas analysis
• vented chamber

ACKNOWLEDGMENTS

The authors would like to thank Mr. Chris Bauer, the late Dr. Bahman Eghball at the USDA-ARS Lincoln, NE, and the student assistants (Sonny Fankhouser, Adam O'Neil, and Aaron Bereuter) for their assistance in soil gas sampling. We also thank the carbon sequestration program team at the University of Nebraska, Lincoln. Development of the automatic soil gas sampler was supported by the U.S. Department of Energy: a) EPSCoR program, Grant No. DE-FG-02-00ER45827 and b) Office of Science, Biological and Environmental Research Program (BER), Grant No. DE-FG02-03ER63639.

Notes

^†Mention of products does not constitute endorsement by the University of Nebraska or the USDA-ARS over other similar products that may be suitable.

¹Mention of products does not constitute endorsement by the University of Nebraska or the USDA-ARS over other similar products.