Agricultural Research Service (ARS) scientists at the National Sedimentation Laboratory in Oxford, Miss., are studying how farming practices and conservation strategies can improve water quality in the Yazoo River Delta and beyond.
As part of this effort, research leader Martin Locke and his colleagues have been tracking changes in the Beasley Lake watershed for more than a decade. During this time, local farmers have shifted from primarily growing cotton to producing corn, soybeans and sorghum. Other farmland has been taken out of production altogether.
Throughout this shift, the researchers monitored a range of biological, chemical and physical factors in Beasley Lake, which flows into the Yazoo River. They also evaluated runoff from edge-of-field sites and developed vegetated buffer zones and slotted inlet pipes to slow water flow and trap agricultural chemicals and sediments in field runoff.
The researchers found that Beasley Lake has improved in clarity, plankton growth levels and fish stocks over the past 11 years. Lake phosphorus levels decreased when farmers began to adopt conservation management practices, and pesticide levels also dropped significantly.
Matt Moore, NSL ecologist, and other scientists also carried out studies using constructed wetlands near Beasley Lake that consisted of a sediment retention pond and two vegetated wetland “cells.”
The scientists found that the wetland vegetation trapped a significant amount of both pesticides, which suggests that constructed wetlands can help reduce the amount of chemicals that are washed out of production fields.