Subsurface Sensing Methods Applied to Vegetative Treatment Areas Used to Manage Cattle Feedlot Runoff

Authors: Eigenberg, Roger; Woodbury, Bryan; Nienaber, John; Spiehs, Mindy

Submitted to: Symposium on Application of Geophysics to Engineering and Environmental Problems Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/9/2009
Publication Date: 4/2/2009
Citation: Eigenberg, R.A., Woodbury, B.L., Nienaber, J.A., Spiehs, M.J. 2009. Subsurface Sensing Methods Applied to Vegetative Treatment Areas Used to Manage Cattle Feedlot Runoff. In: Proceedings Expanding Horizons for Near-Surface Geophysics. 22nd Symposium on the Application of Geophysics to Engineering and Environmental Problems, Ft. Worth, TX, Mar. 29-Apr. 2, 2009,p.862-869. 2009 CDROM.

Interpretive Summary: Cattle producers are seeking alternative ways to handle liquid runoff from feedlots. The traditional method is to collect the runoff in a storage pond for pumping at an opportune time. This approach can lead to problems with odor and with nutrients leeching into the soils under the storage pond. One alternative approach has the approval of the Iowa Cattlemen Association and the Natural Resource Conservation Service. Under this agreement several cattle producers have constructed vegetative treatment systems (VTS). One challenge posed by a VTS is to establish a way to monitor the system performance. This paper describes a method of monitoring VTS performance as applied to a system constructed at the U.S. Meat Animal Research Center (USMARC), Clay Center, Nebraska. Soil conductivity is a measurement that is easily made by using an instrument that can be pulled behind an ATV. Soil conductivity maps were generated on two separate dates separated by approximately 14 months. A program developed by the Soil Salinity Lab at Riverside, CA was used to: 1) determine soil core locations, 2) generate nutrient specific predictive maps based on combined soil core data and a soil conductivity map using statistical methods. Prediction data for the two dates were compared by differencing gridded data of each date. The difference map illustrates management changes that occurred during the interval between the two survey dates. Methodologies described here demonstrate the capabilities of this analysis approach as applied to VTS in operation for eight years. The methods are sensitive enough to measure subtle management changes but robust enough to evaluate overall performance.

Technical Abstract: Monitoring alternative feedlot runoff control technology effectiveness, especially vegetative treatment systems (VTS), is of interest to both cattlemen and regulatory agencies. Producers have constructed VTS in several mid-western states under an agreement with the Iowa Cattlemen Association and the Natural Resource Conservation Service. This paper describes a method of monitoring VTS performance as applied to a system constructed at the U.S. Meat Animal Research Center (USMARC), Clay Center, Nebraska. Soil conductivity maps were generated on two separate dates separated by approximately 14 months. A program, ESAP, developed by the Soil Salinity Lab at Riverside, CA was used to: 1) determine soil core locations, 2) generate nutrient specific predictive maps based on combined soil core data and a soil conductivity map using multiple linear regression methods. The ESAP program suite provided estimates of the primary variable distribution across the VTS based on twelve core sites and high density soil conductivity (ECa) data for both sample dates. Prediction data for the two dates were compared by differencing gridded data of each date. The difference map illustrates management changes that occurred during the interval between the two survey dates. Methodologies described here demonstrate the capabilities of this analysis approach as applied to VTS in operation for eight years. The methods are sensitive enough to measure subtle management changes but robust enough to evaluate overall performance. These same methods have been applied to multiple sites in Iowa and have been reported previously (Woodbury et al., 2007).