Bacteria Runoff BMPs for Intensive Beef Cattle Operations.

摘要

According to the 2008 Water Quality Inventory and 303(d) List, 291 of the 516 impairments (i.e. 56%) were the result of excessive bacteria. Modeling and bacteria source tracking has identified grazing cattle as a source of this bacterial contamination. To help address this, the Natural Resources Conservation Service (NRCS) funded this project to evaluate the effect of stocking rate on pathogen transport from beef cattle operations and develop guidance for landowners on restoring water quality. The project included three tasks: (1) Project Coordination and Administration, (2) Assess Bacteria Runoff from Intensively Managed Beef Cattle Operations, and (3) Technical Transfer. Task 1, Project Coordination and Administration, consisted of the Texas Water Resources Institute (TWRI) preparing and submitting eleven quarterly progress reports and the final project report, holding 25 coordination meetings, and submitting 12 invoices. To evaluate the impact of grazing management on bacterial runoff (Task 2), TWRI and Texas AgriLife Extension Service (AgriLife Extension) installed three 1-hectare watershed sites at the Texas A&M University Beef Cattle Systems Center (BCSC), located near College Station. Sites were bermed and equipped with 90o v-notch weirs, ISCO samplers with bubble flow meters, and a rain gage. TWRI and AgriLife Extension maintained these watershed sites for two years, conducting over 30 site visits. A variety of stocking rates were evaluated. Site BB1 was ungrazed. Site BB2 was stocked at typical stocking rates (SR) for the area (i.e., 3-4 acres per animal unit (AU)). Site BB3 was stocked at a rate twice that of site BB2. Over the course of the project, six grazing treatments were conducted at sites BB2 and BB3.