Submitted to: International Soil and Water Conservation Conference
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2006
Publication Date: 8/28/2006
Citation: Franzluebbers, A.J. 2006. Stratification of soil organic carbon and its impact on environmental quality [abstract]. Managing Agricultural Landscapes for Environmental Quality; Strengthening the Science Base, October 11-13, 2006, Kansas City, Missouri, Workshop Program and Abstract Book. p. 77.
Technical Abstract: Stratification of soil organic C occurs when plant residues are placed at the soil surface and disturbance of soil is minimized. Vertical stratification of soil organic C within the soil profile is common in forests, grasslands, and managed agroecosystems using conservation tillage, cover cropping, and/or pasture-crop rotations. The extent of soil organic C stratification in any particular soil can be related to a number of management factors, which ultimately help to improve key environmental services. Soil organic C is a key component of many soil functions by providing the energy, substrates, and biological diversity to support biological activity, which affects (1) aggregation (important for habitat space, oxygen supply, and preventing soil erosion), infiltration (important for leaching, runoff, and crop water uptake), and decomposition (important for nutrient cycling and detoxification of amendments). Lack of residue cover and exposure of soil to high-intensity rainfall can result in poor aggregation, reduced plant water availability, erosion, and off-site impacts of sedimentation, poor water quality, and rising atmospheric carbon dioxide concentration. A review of literature and recently collected data will be used to relate soil organic C stratification to water runoff quality and mitigation of greenhouse gases. Despite high concentrations of surface soil nutrients associated with high soil organic C stratification, water runoff volume and quality do not appear to be at much greater risk of loss, except for an increase in bioavailable P. Sequestration of C in surface residue and soil can reduce net C flux to the atmosphere and improve soil tilth and overall soil fertility. Further research avenues will be suggested to quantify these important relationships on a landscape level.