|O'DELL, DEB - University Of Tennessee|
|EASH, NEAL - University Of Tennessee|
|HICKS, BRUCE - Metcorps|
|OETTING, JOEL - University Of Tennessee|
|Sauer, Thomas - Tom|
|LAMBERT, DAYTON - University Of Tennessee|
|LOGAN, JOANNE - University Of Tennessee|
|WRIGHT, WESLEY - University Of Tennessee|
|ZAHN, JAMES - Dupont Tate & Lyle Bio Products Company|
Submitted to: Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2017
Publication Date: 2/15/2018
Citation: O'Dell, D., Eash, N.S., Hicks, B.B., Oetting, J.N., Sauer, T.J., Lambert, D.M., Logan, J., Wright, W.C., Zahn, J.A. 2018. Reducing CO2 flux by decreasing tillage in Ohio: Overcoming conjecture with data. Journal of Agricultural Science. 10(3). https://doi.org/10.5539/jas.v10n3p1.
Interpretive Summary: Carbon dioxide is released to the atmosphere when organic matter in the soil decomposes. Practices that slow down decomposition tend to build organic matter in the soil and have less carbon dioxide released to the atmosphere. This is good for soil health and good for reducing the greenhouse effect. In this study, carbon dioxide exchange with the atmosphere was measured above two corn fields in Ohio, one that had the soil tilled and the other that was not tilled (no-till). Early in the growing season both fields released carbon dioxide to the atmosphere as the crop residues from the previous season decomposed. Later, as the crops grew and took up carbon dioxide from the atmosphere, the surface consumed more carbon dioxide than it released. By the end of the measurement period the no-till field had taken up more carbon dioxide than the tilled field. This result indicates that the no-till field released less carbon dioxide to the atmosphere and will likely increase the amount of soil organic matter. These results are of interest to growers, technical field staff, county, state, and federal conservation agency staff, and researchers concerned with soil management effects on greenhouse gas production and soil health.
Technical Abstract: Soil could become an important sink for atmospheric carbon dioxide (CO2) as global agricultural greenhouse gas emissions continue to grow, but data to support this conjecture are few. Sequestering soil carbon (C) depends upon many factors including soil type, climate, crop, tillage, nitrogen fertilization rates, cropping history and rotation, as well as the degree of soil degradation. Reduced tillage, especially no-till, can result in reduced CO2 emissions and C sequestration if sufficient biomass is produced and near-continuous ground cover maintained. In this study we used micrometeorology to estimate the CO2 flux between the surface and the atmosphere by measuring changes in CO2 concentration and energy in and above the crop canopy or soil surface. The study used the Bowen ratio energy balance (BREB) technique to quantify differences in CO2 fluxes between contrasting tillage practices. The sum of our flux calculations showed that no-till sequestered 263.2 g CO2 m-2 (90% confidence interval -432.1 to -99.9) while the tilled plot emitted 146.4 g CO2 m-2 (90% confidence interval -53.3 to 332.2) during 104 days of the 2015 growing season in north-central Ohio. In contrast to the conclusions of most recent discussions on this topic, the present study indicates that tillage practices can affect C sequestration in a way that helps ensure long-term soil and crop productivity.