Submitted to: International Symposium on Precision Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: January 31, 2008
Publication Date: N/A
Technical Abstract: Cattle feedlot nutrient waste management is a topic of increasing environmental, sociological, and regulatory concern. This report investigates methods adapted from the management of saline soils for application to feedlot surface management as well operation of a vegetative treatment area (VTA) utilized to control feedlot runoff. Soil conductivity maps were collected from a feedlot pen and a vegetative treatment area (VTA) site. A program, ESAP, developed by the Soil Salinity Lab at Riverside, CA was used to: 1) determine soil sample locations, 2) generate nutrient specific predictive maps based on combined soil sample data and a soil conductivity map using multiple linear regression (MLR) analysis. An electromagnetic induction soil conductivity meter was used to collect apparent soil conductivity (ECa) from a feedlot pen and a research VTA at the U.S. Meat Animal Research Center, Clay Center, NE. Results from the feedlot site indicate correlations between ECa and associated volatile solids (r2 = 0.92). Volatile solids are closely associated with nutrients (r2 = 0.97 for total N and r2 = 0.95 for total P). The VTA was analyzed and Cl- (an indicator ion for feedlot runoff) was found to be associated with ECa (r2=0.86). The ESAP program suite provided reasonable estimates of the primary variable distribution across the feedlot and the VTA based on soil sample data combined with high density soil conductivity (ECa) data. Maps of nutrient distribution were produced as well as tables that list nutrient loading with percent area contributing. Identifying areas of excessive nutrient buildup allows for site-specific management, improving system performance and sustainability while reducing nutrient losses to the environment.