Effect of Controlled Drainage and Vegetative Buffers on Drainage Water Quality from Wastewater Irrigated Fields

Lagoon effluent is routinely applied to agricultural fields as fertilizer to utilize nutrients derived from animal manures. In humid regions, effluent is also applied to fields in order to manage the lagoon stage within acceptable levels. To minimize the risk of applied nutrients being transported to surface waters, best management practices such as vegetative buffers and controlled drainage are often recommended. This paper presents the results of a field study to evaluate the effectiveness of controlled drainage and vegetative buffers in reducing the transport of wastewater nutrients from land application fields. Swine lagoon effluent was spray irrigated to Bermudagrass fields drained by a parallel ditch system. Drainage outflow was monitored continuously for a 3 year period. Vegetative buffers reduced the average concentration of phosphorus by about 30%, but the average concentration of nitrogen was not affected. Controlled drainage resulted in higher individual event nitrogen concentrations, which wer...