Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2007
Publication Date: 9/16/2007
Citation: Woodbury, B.L., Eigenberg, R.A., Nienaber, J.A. 2007. Spatial Nutrient Distribution of VTA Pilot Sites in Iowa. In: Proceedings, International Symposium on Air Quality and Waste Mgmt for Agriculture, Sept. 15-19, 2007, Broomfield, CO. 2007 CDROM 701P0907cd Interpretive Summary: Feedlot owners are interested in controlling runoff from their operations and protecting the environment. Traditionally, runoff is collected and stored for long periods before being applied to crop land as irrigation and fertilizer. A method that uses the runoff to raise hay without storing the water has been developed. Six sites in Iowa were selected to determine how well this method works. Initial condition of the hay field soil was determined to understand how effective the hay crop was at using the runoff water.
Technical Abstract: Cattle feeding operators are interested in alternative runoff control and treatment systems that eliminate long-term liquid storage; however, the feasibility and sustainability of these systems is yet to be determined. Six sites in Iowa utilizing vegetative treatment areas (VTAs) have been constructed to demonstrate their feasibility and sustainability for feedlot runoff control. These sites represent an array of climate, site considerations (i.e. topography, soil texture, management, etc.), and design. A geospatial statistical method using multi-linear regression (MLR) models combined with soil analysis was used to predict nutrient distributions and mean concentrations. The overall objective was to report the preliminary chloride, total nitrogen (TN), and total phosphorus (TP) nutrient distribution and mean concentrations in the VTAs for two of the six sites. Some of the VTAs appear to have a history of feedlot runoff; however, the extensiveness of this history is complicated by site construction. Mean concentrations for chloride, TN, and TP were either calculated by MLR model or by actual soil analysis. When MLR model fit was sufficient for determining predicted nutrient distributions, these distributions were predominately clustered at the low end expected for VTAs with many years of operation. The preliminary analyses appear to have provided sufficient base-line understanding as to the status of these VTAs at the on-set of their operation. This information will be used with similar analyses after subsequent years of operation to determine overall VTA feasibility and sustainability for controlling feedlot runoff.