Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2004
Publication Date: 4/1/2005
Citation: Arriaga, F.J., Lowery, B. 2005. Spatial distribution of carbon over an eroded landscape in southwest wisconsin. Soil and Tillage Research. 81:155-162. Interpretive Summary: Soil carbon plays an important role in crop production and environmental quality. However, carbon in soil varies with depth and position in a field. Information describing soil carbon distribution in a field can be of great help for management efforts. A method to display three-dimensional (3-D) soil carbon variations in fields was developed using information obtained from soil samples, a global positioning system (GPS), and a device that measures soil strength. The 3-D map provides a better way of displaying carbon variations within a field. Soil carbon information, such as that described here, can be very valuable for soil management and could be used to determine possible carbon storage credits.
Technical 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 (3-D) 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 3-D viewing was developed of soil C distribution for this eroded landscape. The 3-D 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 0.72 ha 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.