Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/1998
Publication Date: N/A
Citation: Huggins, D.R., Buyanovsky, G.A., Wagner, G.H., Brown, J.R., Darmody, R.G., Peck, T.R., Lesoing, G.W., Vanotti, M.B., Bundy, L.G. 1998. SOIL ORGANIC C IN THE TALLGRASS PRAIRIE-DERIVED REGION OF THE CORN BELT: EFFECTS OF LONG-TERM CROP MANAGEMENT. Soil & Tillage Research. 47:219-234. Interpretive Summary: Rising levels of atmospheric carbon dioxide, a greenhouse gas, have resulted, in part, from the release of soil-derived carbon dioxide following the cultivation of native prairies. The depletion of soil C from native levels suggests that considerable storage potential may exist within soils to recapture atmospheric carbon dioxide, thereby mitigating greenhouse effects. In order to evaluate management effects on the soils storage capacity for carbon dioxide, soil carbon dynamics of long-term studies within the tallgrass prairie region of the U.S. were assessed. Our analysis was based on data from Sanborn Field, MO, the Morrow Plots, IL, and other studies near Mead, NE, Lamberton, MN, Arlington, WI and Lancaster WI. We concluded that rapid (1 to 40 years) losses and gains of soil carbon consist primarily of easily decomposable organic materials. Losses of easily decomposable soil carbon are promoted by low returns of crop residues and roots and intensive tillage. Gains in easily decomposable soil carbon are promoted by returning large amounts of residue to the soil and limiting soil tillage. A large capacity to store additional carbon exists in the tall-grass prairie region if easily decomposable carbon levels are increased. This capacity for increased soil carbon storage will vary considerably, however, among sites and be dependent on the initial levels of easily decomposable carbon and the ability of management practices to stabilize large inputs of carbon from crop residues and roots.
Technical Abstract: Concerns with rising atmospheric levels of CO2 have stimulated interest in carbon flow in terrestrial ecosystems and the potential for increased soil C sequestration. Our objectives were to assess land management effects on soil organic carbon (SOC) dynamics and SOC sequestration for long-term studies in the Tallgrass prairie region of North America. Major losses of SOC following conversion of native prairie to arable agriculture at Sanbor Field and the Morrow Plots were rapid (20 to 40 yrs), occurred in response to greatly reduced C inputs and accelerated C decay rates, and had largely abated by the mid-1900's. Losses of SOC occurred mainly in easily decomposable, labile C fractions. At Sanborn Field, modeled labile SOC was reduced to 4% of native prairie levels for treatments with low C inputs. A large capacity for soil C sequestration likely exists in the Tallgrass prairie region, if labile C pools can be replenished. This agroecosystem has a strong C decomposition regime and increased sequestration of labile will rely on management practices that increase C inputs (i.e. fertilization, returning crop residues) and stabilize labile C (i.e. perennial cropping, reduced tillage). The capacity for soil C sequestration, however, will vary considerably among sites and be dependent on initial levels of labile SOC and the ability of management practices to stabilize greater inputs of labile C.