Agricultural Land Management: Water Quality Impacts

Restoring and maintaining the health of the Chesapeake Bay is the focus of many William and Mary professors – especially those involved with the interdisciplinary Environmental Science and Policy program. It came as no surprise, then, that geology professors Jim Kaste and Greg Hancock decided to study the effectiveness of riparian buffers on preventing agricultural runoff from entering the bay watershed. Funded by Virginia Environmental Endowment, Kaste and Hancock now lead a team of undergraduates into the field, collecting samples and trying to determine whether the Virginia mandate of a buffer zone—one no smaller than 100 feet—is enough to make a difference in water quality.

The team began by identifying the slopes of agricultural fields that border tributaries of the James and York Rivers—two watersheds characterized by short transport distances to the Chesapeake Bay. They then collected soil cores to a depth of 30 centimeters in both agricultural and riparian zones, analyzing them to determine whether levels of nitrogen and phosphorus are reduced as they pass into and through the buffer zone and into open waters. Additionally, Kaste and Hancock measured overland flow and sediment deposition using radioactive cesium that was deposited on the land during 1950s and 1960s, when atmospheric testing of nuclear weapons occurred. The cesium, spread evenly across the land’s surface, acts as a marker though which post-1967 sediment movement might be tracked.

The group’s initial research is occurring on four different farms on Virginia’s Middle Peninsula. In addition, the team conducts work on two forested, control sites not affected by agricultural landuse. Assisting Kaste and Hancock are Morgan Stumb ’10 and Eric Newman ’10, geology majors who are using the work as part of their senior honors projects. Stumb is focusing on the use of cesium as a tracer element in determining sediment movement from the farm fields through the forest. Newman is looking at the groundwater flow.

William and Mary’s intimate, liberal arts environment fosters an interdisciplinary dialogue that is critical for projects such as this one. Hancock hopes that their work will help bring about changes in how people approach environmental problems – utilizing aspects of data-collection and observation to inform processes that have formerly relied heavily on speculation and planning on paper. Kaste and Hancock recognize the importance of a combination of social, scientific, and political approaches. The results and applications of their research will be presented in both professional and community settings. They also plan on writing white papers for non-scientific agencies and organizations and would like to publish their work in a peer-reviewed professional journal in order to reach a larger academic audience. A short video on the project may be found on the William and Mary website.

“We may find some interesting things in a year or two,” Kaste states in a December interview for a Faculty Feature, “and I have a feeling it’s going to open up a few cans of worms here and there.”