Water Quality of Runoff and Leachate from an Improved Dairy Loafing Area

Abstract

To lessen soil erosion due to high animal stocking rates on small Georgia dairies, the Natural Resources and Conservation Service (NRCS) recommends a system that utilizes geotextile material covered with crusher run gravel as a soil cover in high animal traffic areas. Soil erosion is dramatically reduced, yet due to the large accumulation of manure, questions remain concerning water quality with these systems. At a 120 cow dairy in Oglethorpe county Georgia, a loafing lot utilizing this system was constructed on a Pacolet sandy loam soil (clayey, kaolinitic, thermic, Typic Kanhapludult). Runoff water and leachate were characterized by storm events for water balance and chemical information. Surface runoff water typically contained levels of NH₄-N, and P₄-P that exceeded EPA guidelines for surface water. Sub-surface drainage intercepted by tile drains had N₃-N levels ranging from 10 to 40 ppm exceeding the EPA drinking water standard. It is recommended that surface water running off improved loafing lots either be routed to a wastewater lagoon for irrigation, or to adjacent hay fields to reduce the impact of excess nutrients to surface waters.