The Effectiveness of Saturated Buffer Strips.

The Gulf of Mexico's hypoxic zone is being created by excess nitrogen from the Mississippi River. Saturated buffer strips, a new form of best management practices, can be used to capture water from field tile lines and force it to percolate laterally through the soil allowing for denitrification. The objective of this study was to quantify the effectiveness of a saturated buffer strip to denitrify nitrate. The location for this study was Elm Creek, a first order stream in the Blue Earth watershed in south central Minnesota. Observation tubes where placed at the inflow and outflow of the saturated buffer strip so that water samples could be taken. Water samples were also taken from an upstream and downstream location to quantify nitrogen reduction within the stream itself. Results show that during low flow events nitrate nitrogen was reduced. Stream reduction of nitrate nitrogen was also observed during low flow conditions. However during high flow conditions the saturated buffer strip did not reduce nitrate nitrogen as effectively when compared to low flow due to limited residence time. Farmers should take saturated buffer strips into consideration when their fields are adjacent to streams as a potential best management practice.