Location: Dairy Forage ResearchTitle: Bringing a needle to a laser fight: comparing greenhouse gas sampling methods with gas chromatography and fourier transform infrared spectroscopy Author
|Campbell, C. - University Of Wisconsin|
|Collier, Sarah - University Of Wisconsin|
|Ruark, Matthew - University Of Wisconsin|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2015
Publication Date: 11/15/2015
Citation: Campbell, C., Collier, S.M., Ruark, M.D., Powell, J.M. 2015. Bringing a needle to a laser fight: comparing greenhouse gas sampling methods with gas chromatography and fourier transform infrared spectroscopy [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. [CD ROM]. Version 1.1. Madison, WI: ACS Societies.
Technical Abstract: As scientists, producers, policymakers, and the general public become more concerned about impacts of climate change, there is an increasing need to understand and quantify greenhouse gas emissions from agricultural practices, which often feed into global, multi-institution databases. Current best practices allow for a variety of sampling and analytical techniques, including approaches such as syringe sample collection followed by gas chromatography (GC) in the laboratory, and in-field Fourier transform infrared spectroscopy (FTIR). However, to date only limited analysis has been undertaken to investigate the comparability of data generated through these differing approaches. This is of particular relevance where large databases – such as those used in crop production and climate modeling – will be populated by multiple data streams possibly derived through varying techniques. The goal of this study was to determine if two technologies, GC and FTIR, produce comparable results both in measurement of absolute gas concentration above the soil as well as rate of flux from the soil. The study was conducted using insulated stainless steel closed static chambers, with modified fittings to allow samples to be taken simultaneously from the same chamber headspace with both sampling methods. Comparisons were made on four soil types (Plano silt loam, St. Charles silt loam, barnyard sand bedding, and barnyard mulch bedding) and in three agricultural production practices (continuous corn, a corn-alfalfa rotation, and dairy barnyards). Both methods measured CO2, N2O, and CH4 emissions from soil. Preliminary results show that CO2 emissions follow a strong 1:1 relationship between GC and FTIR, while N2O emissions are more variable in FTIR readings at low concentrations than GC. Analyses on all soil types, agricultural systems, and flux calculations will be presented.