2008 Joint Annual Meeting (5-9 Oct. 2008): Soil Tillage Effects on the Contributions of Soil and Plant C Pools to CO2 Emissions.
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746-21 Soil Tillage Effects on the Contributions of Soil and Plant C Pools to CO2 Emissions.



Wednesday, 8 October 2008
George R. Brown Convention Center, Exhibit Hall E
Ravindra Ramnarine and R. Paul Voroney, Land Resource Science, University of Guelph, Guelph, ON N1G 2W1, Canada
Soil management practices such as tillage may impact CO2 emissions in agricultural soils due to their effect on soil organic matter (SOM) components and dynamics. The objective of this study was to identify the carbon substrates contributing to CO2 emissions, by measuring the δ13C of soil organic carbon pools and crop residue carbon inputs on conventional and no-tilled plots cropped in a rotation of C3 (soybean - Glycine max L.; winter wheat - Triticum aestivum L.) and C4 species (corn - Zea mays L.). Measurements were made of the organic carbon content and δ13C of total soil organic matter, plant residues and soil microbial biomass. A laboratory incubation was carried out to measure the δ13C of CO2 derived from microbial respiration. Density separation followed by acid hydrolysis was employed to separate the SOM pools into light, heavy and recalcitrant fractions.  Integration and validation of experimental results will be carried out using the DAYCENT soil-plant ecosystem model.  The expected output of this research includes a better understanding of CO2 fluxes due to agricultural activities and soil biophysical processes; with the potential for identifying management strategies for minimizing emissions.
See more of: Soil Biology: Implications to Carbon and Nitrogen Dynamics (Posters)
See more of: S03 Soil Biology & Biochemistry