Source: UNIV OF WISCONSIN submitted to NRP
CARBON, NITROGEN, AND PHOSPHORUS CYCLING IN ERODED SOIL LANDSCAPES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
0198101
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2003
Project End Date
Sep 30, 2007
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIV OF WISCONSIN
21 N PARK ST STE 6401
MADISON,WI 53715-1218
Performing Department
SOIL SCIENCE
Non Technical Summary
Reduced crop land productivity from soil erosion costs an estimated $40 billion/yr; environmental costs are an estimated 3.1 billion/yr. Addition of organic materials (manure) provides some restorative effect but can pose an environmental hazard due to P and N loss in runoff water. We will evaluate erosion's impact on C, N, and P redistribution in an eroded landscape and assess use of animal waste on restoration of eroded land and environmental impacts.
Animal Health Component
70%
Research Effort Categories
Basic
20%
Applied
70%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1040110201025%
1020110201075%
Goals / Objectives
(1) Determine the distribution of carbon, nitrogen, and phosphorus in soils of eroded landscapes; (2) Assess management effects on eroded soil productivity and quality of soil, air and water resources.
Project Methods
Objective 1. Degradation and redistribution of carbon and phosphorus in soils of closed landscape systems. Research will be conducted on our existing plots (established as a part of the original NC-174 research project in 1985) at the Lancaster Experimental Farm. The site is located on a Dubuque silt loam soil. We have identified three levels of erosion at the site and we have three replicates for each level of erosion. Over the past 13 years we have applied animal waste to one-half of each plot in an attempt to restore the eroded land. NC-174 Soil Carbon Sampling Protocol: Three soil cores will be collected with a 1.2-m long 6.0-cm diameter steel sampling tube containing a 5.7-cm acetate liner (to prevent sample contamination) to a minimum depth of 1 meter from each treatment. The acetate liners containing the sample core will be removed from the steel tube, capped with plastic caps, and sealed with duct tape for transportation to the laboratory for processing. In the laboratory, the cores will be sectioned into 5-cm, 15-cm, or 30-cm sections and core bulk density will be determined on each section. Each core section will constitute one soil sample. The soils will then be air-dried and crushed to pass a 2-mm screen. Samples will be collected at the start, in the middle, and end of each growing season. Approximately 10- to 15-gram subsamples will be further ground to pass a 60-100 mesh screen for total C analysis. Total C analysis will be performed by high temperature combustion. Organic C will be determined by subtracting inorganic C values from total C values. Analysis of samples for C determination will be performed with a carbon analyzer. Inorganic C data will be included when data are reported since there is very little information in the literature on C sequestration as inorganic C in agricultural systems. Subsamples of the soil cores will be sent to the UW-Soil and Plant Analyses Laboratory for analyses of N and P. These samples will be analyzed for total N and nitrate-N, and total P and water soluble P. Objective 2. Assess management and erosion effects on eroded soil productivity and quality of soil, air, and water resources. Soil and crop management methods to be investigated for the maintenance and/or restoration of soil productivity on eroded soils will be based on evaluation of the literature, assessment of current research, simulation modeling using an existing data base (1st phase of project) to identify limiting factors of a specific soil, and field testing of promising management alternatives. Long term data are necessary to adequately evaluate the management-climate interactions on yields.

Progress 10/01/03 to 09/30/07

Outputs
The soils in Southwestern Wisconsin were developed in varying depths of loess deposited on existing soils developed from sedimentary rock. These soils have undergone considerable post cultivation erosion. Soil erosion has played a significant role in reshaping and defining the current landscape of this section of Wisconsin, which did not undergo glaciation during the last ice age, and appears to never have had glacial activity. Depth of the loess varies as a function of its distribution during deposition and past erosion. Aspects of this project date back to our initial project started in 1983, thus we have conducted research for more than 20 years assessing the impact of erosion on soil productivity under three levels of erosion. For several years we evaluated the role of carbon in this soil including its impact on agricultural chemical leaching. Leaching and spatial distribution of carbon (C) within a soil profile and across a landscape are influenced by many factors such as vegetation, soil erosion, water infiltration, and drainage. We measured C distribution and leaching for three levels of erosion (slight, moderate, and severe) and developed a three-dimensional (3-D) map of the site using a profile cone penetrometer. 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 carbon distribution was created for this landscape using C content information obtained from soil samples. Using C distribution for the upper two horizons we developed a 3-D map 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 of total C in the surface (Ap) horizon and 61 Mg/ha in the Bt1 horizon. 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. However, we did not find a good relationship between C leaching and agricultural chemical leaching as we had hypothesized.

Impacts
A three-dimensional (3-D) soil map for an eroded landscape has been developed and this allows for displaying the depth of topsoil on a landscape scale. The depth of soil can be related to the amount of cultivation-related erosion. When one views the landscape and depth of soil lost by erosion in a 3-D format, it is clear that the effect of soil erosion on this landscape is much greater than previously estimated. One can also link the amount of erosion to the loss of soil carbon and make better estimates of the total amount of carbon in the soil on this eroded landscape.

Publications

  • Arriaga, F.J., and B. Lowery. 2004. Soil physical properties and corn yield of an eroded soil as affected by long-term cattle manure applications. Soil Sci. 168:888-889.