Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 1, 2004
Publication Date: July 4, 2004
Citation: Owens, L.B., Shipitalo, M.J. 2004. Rate of soil carbon loss resulting from tillage. In: 13th International Soil Conservation Organization Conference Proceedings, July 4-8, 2004, Brisbane, Australia. Paper 772. Interpretive Summary: Comparison of soil organic matter in the top 12 inches of soil under 5 different management practices showed that there was less soil organic matter with major tillage than with no tillage or meadow. Meadow soil had more organic matter than soil under long-term no-till, except when there were annual additions of manure. Soils which had been tilled for several consecutive years had the lowest levels of soil organic matter of the 5 practices studied. Tillage by moldboard plowing redistributed the organic matter within the plow layer by moving organic matter from the surface to lower in the plow layer. Even though this study showed that after one year of tillage the total organic matter in the soil did not change much, it also showed that multi-year tillage reduces soil organic matter, and that this reduction occurs over a few years rather than occurring mostly with the first tillage. Although there are many detrimental aspects to soil tillage, including destruction of soil structure, a one-time tillage will not cause great carbon loss. This could have great impact in areas where carbon credits for management practices are established for trading or cash values. Thus, anyone dealing with carbon credits will be affected, e.g. producers, utility companies.
Technical Abstract: Land management practices can have major impacts on soil carbon levels. A 5-year study was conducted to evaluate soil carbon levels with different management practices and to ascertain the rate at which carbon is lost due to tillage. At the North Appalachian Experimental Watershed near Coshocton, Ohio (USA), multi-year conventional tillage (moldboard plowing followed by disking) with corn (Zea mays L), first year plow with corn, meadow, and multi-year no-till corn with and without manure were evaluated. After the first year of conventional tillage, total carbon in the 0-2.5 cm soil layer (3.5 Mg C/ha) was only 41 and 46% of the carbon in the 0-2.5 soil layer of multi-year no-till corn (8.6 Mg C/ha) and meadow (7.7 Mg C/ha) areas, respectively. However, in the 0-30 cm soil layer, carbon levels were similar for first year tillage, no-till, and meadow (41.7, 41.4, and 39.4 Mg C/ha, respectively). The results indicated that one year of conventional tillage greatly altered the distribution of carbon within the plow layer but did not have a detectable affect on total carbon within the plow layer. After 5 years of tillage, however, soil carbon amounts and concentrations were similar to those in the multi-year plowed soil.