MANAGEMENT OF A VEGETATIVE TREATMENT SYSTEM TO REDUCE NUTRIENTS IN BEEF CATTLE FEEDLOT RUNOFF
Agroecosystem Management Research
2012 Annual Report
1a.Objectives (from AD-416):
1) Develop a vegetative treatment system to treat runoff from a beef cattle feedlot;.
2)operate the system in conjunction with a real-world production environment;.
3)evaluate the effectiveness of the treatment system to remove nutrients, pathogens, and pharmaceutical compounds from the runoff.
1b.Approach (from AD-416):
An eight cell vegetative treatment area will be used to treat runoff from a beef cattle feedlot. Feedlot runoff water collected in small basins will be pumped onto the cells at defined rates, and water and soil samples will be collected. Experiments with clean groundwater will also be used to examine the effect of clean rainfall runoff from the cells.
Water and/or soil samples were collected with help from UNL collaborators from the vegetative treatment system (VTS) demonstration site near Rockford, NE on ten occasions since the beginning of this project. Three types of water samples were collected including rainfall runoff from the vegetative treatment areas (VTA), rainfall runoff from the feedlot applied to the VTA, and excess feedlot runoff that was not adsorbed by the VTA. Soil sampling was also conducted on three dates—two dates for soil profiles and on one date a time series study were conducted. Soil profiles were collected in 2010 and 2011 to a 50 cm depth in four treatment cells at five locations along the wastewater flow path. A berm area between treatment cells that did not receive feedlot runoff served as a control site for the other soil samples.
Pharmaceutical compounds were extracted from soil profile samples and analyzed by UNL collaborators at three sites in cell 3 starting from near the application pipe and ending at the downslope end of the cell. Out of a possible seventeen pharmaceutical compounds, only three were routinely detected. These included chlorotetracycline, monensin, and tetracycline. Tylosin was detected in a single sample. Across the depth profile, concentrations of pharmaceutical compounds were greatest at the surface and decreased rapidly to a depth of 50 cm. Typically, detection of pharmaceuticals was only to a depth of 30 cm.