Premium
Automated Soil Monolith‐Flux Chamber System for the Study of Trace Gas Fluxes
Author(s) -
Thomson Petra E.,
Parker John P.,
Arah Jonathan R. M.,
Clayton Helen,
Smith Keith A.
Publication year - 1997
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1997.03615995006100050006x
Subject(s) - soil water , flux (metallurgy) , trace gas , environmental science , soil gas , diurnal temperature variation , soil science , hydrology (agriculture) , sampling (signal processing) , monolith , mineralogy , chemistry , atmospheric sciences , geology , physics , biochemistry , geotechnical engineering , organic chemistry , detector , optics , catalysis
Soils are the major source of atmospheric N 2 O, and better estimates of fluxes are needed to improve the input to climatic general circulation models. We developed a system in a semicontrolled environment to investigate relationships between fluxes of N 2 O and controlling variables. It consists of 12 soil monoliths (1‐m diam., ≈ 0.6 m deep) in glass fiber casings, the tops of which have been converted into gas flux chambers. These chambers are connected to a gas chromatograph for measurement of N 2 O and CO 2 . Gas sampling and analysis is computer controlled and can be done continuously. Temperatures and soil water potential are also recorded continuously. The system has performed reliably since continuous operation began in September 1993. We conducted three experiments, examining the effects of soil water potential, organic matter input, and diurnal temperature variation on N 2 O fluxes, to illustrate the capabilities of the system. In these experiments, the major emissions of N 2 O (>800 εg N 2 O‐N m −2 h −1 ) occurred when the water potential was above −5 kPa. When plant material was incorporated into the soil, a highly significant correlation was found between N 2 O and CO 2 emissions; the N 2 O emissions showed pronounced diurnal cycles, with the maxima occurring at night, 4 h after the temperature maxima at 0.1‐m depth. Data interpretation was greatly aided by the frequency and continuity of measurement.