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United States Department of Agriculture

Agricultural Research Service

Title: Carbon Concentrations and Transport in Sediment Leaving Small Tilled Watersheds

Authors
item Owens, Lloyd
item Malone, Robert
item Starr, G - OHIO STATE UNIVERSITY
item Lal, R - OHIO STATE UNIVERSITY

Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 24, 1999
Publication Date: N/A

Technical Abstract: At the USDA-ARS research station near Coshocton, Ohio, various conservation tillage practices including corn/soybean rotations with no-till, chisel-plow, paraplow, and disking preceding the corn and soybean crops of a corn/soybean/wheat-meadow rotation are being studied on small watersheds (0.55 - 0.79 ha). Each small watershed is instrumented with a 60-cm H-flume mounted on a concrete approach, and a Coshocton wheel for collecting a proportional sample of water and sediment. Over a 13 year period, samples of sediment deposited in the flume approach and in runoff were collected and stored. These stored sediment samples have been analyzed for total carbon, and comparisons of soil carbon have been made among management practices. Weighted averages of soil carbon in the sediment that passed through the flumes during the treatment periods may not differ significantly among tillage treatments, although no-till was the ehighest (2.8%) and chisel-plow was the lowest (1.9%). Weighted averages o soil carbon in the flume floor sediments were slightly lower with no-till being the highest (2.3%) and chisel-plow being the lowest (1.7%). For comparison, weighted soil carbon averages in sediment that passed through flumes from small fertilized, pastured watersheds ranged from 5.2 to 7.2%. Average annual sediment loss was 873, 1312, and 2281 kg/ha for no-till, chisel-plow, and disk, respectively. Annual average transport of soil carbon (the product of total sediment transported times the carbon concentration) in the sediment was 11.9, 12.1, and 17.1 kg/ha for no-till, chisel-plow, and disk, respectively. Although tillage treatments may reduce carbon transport in sediment by lowering concentrations, a greater factor for reducing carbon movement is reducing sediment movement.

Last Modified: 9/21/2014
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