Performance of Vegetative Treatment Systems for CAFOs in a northern subhumid climate

Abstract

<abstract> <bold>Abstract.</bold> A vegetative treatment system (VTS) may be a viable alternative to a basin for controlling and managing feedlot runoff. The objective of this research was to measure the performance of a VTS for controlling runoff from two feedlots. Each VTS consisted of a solids settling basin and a vegetative treatment area (VTA). The inlet to the VTA was actively controlled at each site. Rainfall and VTA inflow were measured at each site. Short crop reference evapotranspiration (ET_o) was used as an estimate of VTA ET_c. Total nitrogen (N) and phosphorus (P) concentrations were measured in samples of the VTA inflow. Total nitrogen, nitrate-N, and Olsen P were measured in soil samples collected from the VTA near the end of each monitoring season. Biomass yield in the VTA was measured and N and P concentrations were measured in the harvested biomass. Three of the six site-years had above-average rainfall and provided strong tests of the VTS. There were no surface water releases at either site during any of the monitoring periods. Phosphorus accumulated in the top 0.6 m of the soil profile. Total N and nitrate-N contents in the soil varied from year to year but did not accumulate. Harvested biomass removed some N and P each year but much more was added to the VTA in the inflow water. These results show that a well-designed and well-managed VTS can be a viable system for managing feedlot runoff and can prevent surface water release.