USE OF MLR TO ESTIMATE NUTRIENT DISTRIBUTION AT WASTE MANAGEMENT SITES--PRELIMINARY REPORT

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

Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Other
Publication Acceptance Date: 5/12/2006
Publication Date: 7/9/2006
Citation: Eigenberg, R.A., Woodbury, B.L., Nienaber, J.A. 2006. Use of MLR to estimate nutrient distribution at waste management sites--preliminary report. American Society of Agri Engineers Special Meetings and Conferences Papers. Paper No. 064056.

Interpretive Summary: Liquid runoff from cattle feeding operations can be either held in long-term storage or momentarily held for solids settling, then discharged for use by vegetation. The second option is generally more environmentally attractive, but has not been fully tested. Nutrient distribution across the grass is an important concern over time. Methods to test distribution can be based on expensive soil core data, or relatively inexpensive mapping of soil electrical conductivity. A combination of the two methods has shown improvement in seeing high nutrient concentration areas. A new method used to study soil salt buildup in western irrigated soils (high salt content) was adapted to study nutrient distribution in a hay field at USMARC. The hay field received feedlot runoff after solids had settled. This paper describes the process and the advantages of this observation method.

Technical Abstract: Soils data can be used to establish nutrient distribution at a selected site; however, soil sampling is labor intensive, costly, and selection of coring sites may be difficult. This study was conducted to determine if methods used in the management of saline soils can be applied to a vegetative treatment area (VTA) utilized to control feedlot runoff. Soil conductivity maps were generated at a VTA site. 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 (MLR) methods. The ESAP program suite provided reasonable estimates of the primary variable distribution across the VTA based on twelve core sites and high density soil conductivity (ECa) data. Preliminary results indicate the ESAP program suite provided a good alternative to the more commonly used method of cokriging. While this initial evaluation is subjective it does provide enough information to support studies that will allow detailed evaluation of the use of ESAP for evaluating alternative runoff control systems.