WASHINGTON – A new type of buffer can help reduce the pollution of lakes and streams caused by fertilizers and other farm products, an agriculture expert said Tuesday.
Kent Rodelius, vice president of the Agricultural Drainage Water Management Coalition, testified before a House Agriculture subcommittee on the growing problem of nutrient pollution in the U.S. The pollution occurs when excess nutrients, primarily nitrogen and phosphorous, get into groundwater and the runoff pollutes streams, rivers and lakes.
The Environmental Protection Agency cites agriculture as a main contributor to nutrient pollution because fertilizers and manure rich with phosphorous and nitrogen produce runoff that funnels into bigger bodies of water. This causes algae blooms that produce harmful toxins, which can kill fish and spoil drinking water.
Efforts to eliminate excess phosphorous from runoff water with regular conservation buffers have not been fully effective, Rodelius said.
“Across much of America we have built thousand of miles of buffers around agricultural fields to improve environmental outcomes,” Rodelius said. “But typically only the surface runoff runs through the buffer, and most of the water circumvents the buffer by running through the tile lines.”
With a saturated buffer, the water table, which lies under the buffer, is raised so the nutrients in subsurface drainage can be removed. The water that reaches lakes and streams after passing through a saturated buffer will have phosphorous levels below the limits of detection, according to a report by the Agricultural Drainage Water Management Coalition published in December of 2015.
The only extra cost when installing a saturated buffer is a control structure to raise the water table and seep lines to distribute water into the buffer, Rodelius said.
“There is no on-farm benefit so incentives will have to come from off the farm to support widespread adoption of this practice,” he said. “But additional incentives could come from payments for ecosystem services and other market mechanisms.”
The Department of Agriculture does not have a standard for the implementation of saturated buffers.