MANAGEMENT OF NUTRIENTS FROM BEEF FEEDLOTS TO PROTECT THE ENVIRONMENT
Location: Environmental Management Research
Title: Soil conductivity and multiple linear regression for precision monitoring of beef feedlot manure and runoff
Submitted to: Journal of Environmental & Engineering Geophysics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 27, 2010
Publication Date: September 1, 2010
Citation: Eigenberg, R.A., Woodbury, B.L., Nienaber, J.A., Spiehs, M.J., Parker, D., Varel, V.H. 2010. Soil conductivity and multiple linear regression for precision monitoring of beef feedlot manure and runoff. Journal of Environmental & Engineering Geophysics. 15:175-183.
Interpretive Summary: Precision farming methods have been applied to crop management with success. Some of the same methods may be used to manage manure from feedlots. This report studies the management of soils with high salt content. Two separate areas: the feedlot surface and hayfields getting runoff from cattle feedlots have high salt concentrations in the soil that can be detected by a soil conductivity meter. A soil conductivity meter was used to study a feedlot pen and a hayfield receiving runoff at the U.S. Meat Animal Research Center, Clay Center, NE. Soil samples were taken from each site. The soil conductivity was higher on the feedlot surface where manure was built up. A computer program, ESAP, was used to analyze the relationship between soil conductivity and the liquid runoff from the feedlot pens. The program provided a map of nutrient locations across a hayfield. Identifying areas of high nutrients on both a feedlot and a field is the key to improved use of nutrients and protection of the environment.
Open-lot cattle feeding operations face challenges in control of nutrient runoff, leaching, and gaseous emissions. This report investigates the use of precision management of saline soils as found on 1) feedlot surfaces and 2) a vegetative treatment area (VTA) utilized to control feedlot runoff. An electromagnetic induction soil conductivity meter was used to collect apparent soil electrical conductivity (ECa) from feedlot pens and a research VTA at the U.S. Meat Animal Research Center, Clay Center, NE. An Exchangeable Sodium Analysis Program (ESAP), developed by the Soil Salinity Lab at Riverside, CA was used to analyze feedlot pens and the VTA. The program directed soil sample site locations and produced models associating ECa to volatile solids (VS) and chloride (Cl-, an indicator ion for feedlot runoff). Results from the feedlot site for two pens with differing management styles indicate positive correlations between ECa and associated VS (r**2** = 0.90, soil mound pen; r**2** = 0.72, manure mound pen). For the VTA, Cl- was found to be associated with ECa (r**2** = 0.86). The ESAP program provided estimates of the secondary variable distribution across the VTA and feedlot pens based on soil sample data combined with high density soil conductivity (ECa) data. The methodology outlined in this research will be useful for identifying areas of excessive nutrient buildup on feedlots and runoff control areas, thereby allowing for site-specific management, improvement of system performance, and sustainability while reducing nutrient losses to the environment.