Research identifying best grasses for roadsidesBy Stewart MacInnis
Spectrum Volume 18 Issue 36 - July 25, 1996
Jody Booze-Daniels is looking for the best grasses to plant in some of Virginia's worst environments, places where the sun blazes down without mercy and where it's a wonder the noxious fumes don't choke everything alive.
A research associate with Virginia Tech's Department of Crop and Soil Environmental Sciences, Booze-Daniels is a member of a team working to identify the best grasses to plant along Virginia's 55,000-mile public-highway system. The goal, she says, is to provide high ground-cover density with persistent growth.
"When you achieve those goals, you're really reducing soil erosion," Booze-Daniels said.
Though the research is not aimed primarily at water quality, she says Virginia Tech's research has definite implications in that regard. Virginia has the third largest state-maintained highway system in the nation, and controlling runoff from its roadsides can have a significant impact on water quality.
In addition to controlling sediment washing into rivers and into the Chesapeake Bay, Booze-Daniels says an aim of the Virginia Tech research is to determine the optimum amount of fertilizer to apply to roadside stands of grass. Apply too little fertilizer and the grass won't thrive; apply too much and that not taken up by the plants will wash into waterways, adding to water pollution.
Creating still greater pressure to find effective and low-maintenance vegetation for roadsides is part of the trend toward leaner budgets in government agencies.
"Our goal is to evaluate grasses that can provide long-term protection and adapt to harsh roadside conditions," she said.
Three years of evaluation have shown that tall fescues, which have dominated the rights of way of Virginia's roadways since the 1950s, are very adaptable, Booze-Daniels says. But it was also found that those grasses generally need more fertilizer than the Virginia Department of Transportation can economically provide.
Fine fescues require less fertilization and have as long-term persistence as tall fescues, she said. The fine fescue grasses, it was found, are better able to adapt to some sites in Virginia than are the tall fescues.
Complicating matters, however, is the fact that Virginia is in the transition zone between warm-season and cold-season grasses.
"The conventional thought was that the fine fescues wouldn't do well in the east, where conditions are generally hotter, but those we tried in Suffolk and Richmond did as well as those in western sites. We're now evaluating fine fescues at sites in Blacksburg, Lynchburg, and Chester. So far, they've done as well as or better than the tall fescues."
Roadside pollution and relentless heat aren't the only challenges to grasses planted along highways. Often, the act of building a highway will create an inhospitable environment.
Cuts through a hillside will sometimes expose compounds once safely sealed under many feet of earth. Those compounds, when exposed to air and environmental factors can create sulfuric acid. In some areas, Booze-Daniels said, the concentration of acid is so great that no grasses can be established.
"We found the situation is very similar to that encountered in strip mines," she says. "So, we're demonstrating to [the Virginia Department of Transportation] how techniques used in the reclamation of strip mines can help solve these problems."
That includes treating sites with yardwaste compost, using the right amount of lime to reduce the potential acidity of the soil (with rates of 10 to 20 tons per acre not unusual), and using legumes, to fix nitrogen in the soil. That, in turn, helps create conditions much more favorable for the growth of grasses.
Additional field work is being done to evaluate how best to maintain vegetation along Virginia's highways. Booze-Daniels said the research should help highway-department personnel with recommendations on the best grasses for certain areas, the best ways to establish and maintain stands of grasses, and methods to remediate areas where it is difficult to impossible to grow vegetation now.