www.elsevier.com/locate/still Soil & Tillage Research 81 (2005) 155–162 Spatial distribution of carbon over an eroded landscape in southwest Wisconsin $ Francisco J. Arriaga a, * , Birl Lowery b a National Soil Dynamics Laboratory, USDA-ARS, 411 S. Donahue Drive, Auburn, AL 36832, USA b Department of Soil Science, University of Wisconsin–Madison, 1525 Observatory Drive, Madison, WI 53706, USA Abstract Spatial distribution of carbon (C) within a soil profile and across a landscape is influenced by many factors including vegetation, soil erosion, water infiltration, and drainage. For this reason, we attempted to determine the soil C distribution of an eroded soil. A three-dimensional (3D) map of a 0.72 ha field with a Dubuque silt loam soil which has three levels of erosion (slight, moderate, and severe) was developed using soil distribution and profile data collected using a profile cone penetrometer (PCP). This map displays the distribution of the total depth of the Ap and Bt1 horizons and the upper part of the 2Bt2 horizon. A map of soil C distribution was created for this landscape using C content information obtained from soil samples. Based on the C distribution in the upper two horizons, a 3D viewing was developed of soil C distribution for this eroded landscape. The 3D assessment of C distribution provides a better means of assessing the impact of soil erosion on C fate. It was estimated that there were 52 Mg ha 1 of total C in the surface (Ap) horizon and 61 Mg ha 1 in the Bt1 horizon for the 0.72 ha area. This increase in C with depth in the soil can be attributed to an increase in clay content and C leaching resulting in stable carbon–clay complexes. The C content was 16.0, 17.5, and 19.0 g kg 1 for the Ap horizon in the slight, moderate, and severe erosion levels, respectively. However, it was estimated that the total C amount in the respective Ap horizons was 28, 14, and 10 Mg ha 1 for the slight, moderate, and severe areas. The Bt1 horizon had 31, 19, and 11 Mg ha 1 of C in the slight, moderate, and severe areas, respectively. For the 0.72ha area, 25% was severely eroded with 31 and 44% being moderate and slight, respectively. Soil C distribution information, such as that presented here, can be very valuable for soil management and could be used to determine possible C storage credits. # 2004 Elsevier B.V. All rights reserved. Keywords: Erosion; Soil carbon; Spatial variability; 3D soil map; Carbon sequestration 1. Introduction $ Mention of company or product name does not constitute Erosion can change the biological, chemical, and endorsement by the USDA-ARS or the University of Wisconsin– physical properties of a soil. Frequently these changes Madison to the exclusion of others. in soil properties can be attributed to changes in C * Corresponding author. Tel.: +1 334 844 0851; fax: +1 334 887 8597. content of the eroded soil. It is difficult to determine a E-mail address: farriaga@ars.usda.gov (F.J. Arriaga). priori the impact of erosion on a given soil. For 0167-1987/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.still.2004.09.004