Planting land closest to streams with native species of trees, shrubs and
grasses-- rather than crops--can help preserve water quality,
Agricultural Research Service scientists
say. ARS studies have shown that the plantings create highly effective natural
riparian buffers that capture field runoff of sediment, fertilizers and other
pollutants and keep it out of the stream.
In Georgia, ARS scientists recently completed a study tracking herbicide
runoff from a corn field into a 150-foot-wide grass and forest buffer. At the
edge of the field, the scientists detected chemical concentrations of 34 parts
per billion. But in the buffer, they detected concentrations of only 1 ppb or
Elsewhere, ARS scientists are testing various warm- and cool-season grasses
farmers can grow to reduce nitrate, another danger to streamwater. The goal:
identify grasses that foster a soil environment necessary for converting
dissolved nitrate into gaseous forms that enter the atmosphere instead of
streamwater. Research shows up to 50 percent of a riparian zone's dissolved
nitrate can be removed in this way.
ARS scientists also provide scientific expertise to state and federal action
agencies, like USDA's Natural Resources
Conservation Service. These agencies help farmers, landowners and others
restore or manage riparian buffers to protect water quality.
Last summer, for example, Maryland joined the
Reserve Program's new state enhancement project. Part of this new project
calls for establishing buffers along Maryland's waterways, including those of
the Eastern Shore. There, nutrient-rich chicken manure may be triggering
outbreaks of the fish-killing microbe Pfiesteria piscicida.
A more detailed report on the latest ARS buffer research appears in the
February issue of Agricultural Research magazine. The story is also on
the World Wide Web at: