227-7 Monitoring Greenhouse Fluxes and Soil Thermal Properties in a Central Missouri Soybean Field Over 5 Years 2004-2008.

Poster Number 223

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Challenges and Innovations in Soil Carbon Stock & GHG Emissions Measurements.
Tuesday, October 23, 2012
Duke Energy Convention Center, Exhibit Hall AB, Level 1
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Stephanie Sale, 820 Chestnut St 307 FH, Lincoln University, Jefferson City, MO and Nsalambi Nkongolo, 830 Chestnut Street, Lincoln University of Missouri, Jefferson City, MO
Greenhouse gases (CO2, CH4 and N2O) emissions were monitored in a soybean field at Lincoln University's Freeman farm from 2004 to 2008. Static and vented chambers of 0.30 m long and 0.20 m diameter were installed at the beginning of each growing season in corn field. The chamber top had a middle hole covered by a stopper and used for air vacuuming and sampling. Soil air samples for determinations of CO2, CH4 and N2O were collected at least twice a month from May to December. The sampling process consisted in closing the chamber two ventilation holes with rubber stoppers, collecting an air sample with a 50 ml syringe and storing it in a 200 ml Tedlar bag. Analysis of CO2, CH4 and N2O from air samples was done within two hours with a Shimadzu GC-14. Soil samples were collected for analysis of chemical and physical properties. Soil temperature (T), thermal conductivity (K), resistivity (R), diffusivity (D) and volumetric heat capacity (C) were directly measured with KD2 probe. A year to year analysis of data showed that the soybean field was a source for CO2 and N2O from 2004 to 2008 as follows: for CO2: 2004<2005>2006<2007>2008 and for N2O: 2004<2005>2006<2007<2008. The soybean field was a sink (2004 >2005) but also a source (2006 >2007<2008) for CH4. Gases fluxes correlated among themselves mainly in 2005. N2O was only correlated with T and only in 2005, 2007 and 2008.  CO2 had more correlations with thermal properties in 2007 and 2008. Correlation coefficients ranged from 0.20 to 0.80. Although the discrepancies in the relationships between gases fluxes and soil thermal properties still show the need for continued research, this study provides useful information that can be used in predictive models of greenhouse gases emissions.
See more from this Division: ASA Section: Environmental Quality
See more from this Session: Challenges and Innovations in Soil Carbon Stock & GHG Emissions Measurements.