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YOUR TURF
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From roadside to rough
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More than 20 grass species were screened for salt tolerance in greenhouse studies at the University of Rhode Island. Photo courtesy of R. Brown |
Rebecca Brown is searching. She has been searching for a long time now, and like most turf breeders, she is looking for a particular grass — or a grass with particular characteristics. The University of Rhode Island researcher’s original quest was to identify native grasses that would thrive on the state’s roadsides (since 1999 the federal government has mandated the use of some native plants in federally funded highway projects). With profuse vegetation covering roadside areas along highways all over the state, how difficult could it be?
It’s not as easy as one might think. Of the naturally occurring grasses in New England, only 43 percent are actually native and only a few are commercially available. Even if they were available, they might not be able to survive harsh roadside conditions: thin, well-drained acidic soil; low fertility; and winter applications of salt for de-icing. Therefore, scientists must test numerous species and ecotypes to determine their fitness for roadside planting.
The biggest challenge facing roadside grasses in New England is a combination of low fertility and the dramatic fluctuation in sodium levels. Root-zone sodium levels can be extremely high in winter and spring — up to 55 deciSiemens/meter, which is very similar to seawater — and so low during the rest of the year that they can’t be detected. Low fertility reduces the ability of the grass to recover from salt damage in winter and drought stress in summer.
Several grass species tolerate high sodium levels, including alkaligrass, buffalograss and blue grama. Quackgrass is also salt-tolerant, and there are salt-tolerant cultivars of perennial ryegrass, tall fescue and red fescue. However, none of these provides a ready solution. Brown says, “None of these grasses is native to southern New England, except blue grama and possibly red fescue.”
Brown screened 48 plants from 21 species in 2007 and 56 plants from 20 species in 2008. Established plants were exposed to increasing levels of sodium chloride, with the salt level increased by 4 deciSiemens/meter every two weeks.
As the greenhouse trials progressed, the plants died off from exposure to higher and higher saline levels. Plants with the most promising characteristics were put into field studies in winter 2007 and harvested this summer. If the harvest yields enough viable seed — which doesn’t always happen — Brown will use that seed to establish turf plots in spring 2009. She will also send some seed out West, possibly to Oregon, for seed production screening. “Oddly enough,” says Brown, “Rhode Island is too rainy to grow grass seed.”
Brown is currently excited about two grasses that are being screened in pots in the greenhouse because, she says, “They might have decent turf characteristics.” If these “decent turf characteristics” hold up, the end result could be a very salt-tolerant turf suitable for roadsides and golf course roughs.
Successful control of emerald ash borer is documented in a video on the newly launched Web site www.treeresearch.org. Hosted by Dave Roberts, Ph.D., a specialist and district horticulture agent with Michigan State University Extension, the video provides information about the signs and diagnosis of emerald ash borer, as well as an overview of the chemicals and fertilizers used to successfully treat ash trees. Visit www.treeresearch.org for more information. Bayer Environmental Science sponsored the meeting of turfgrass weed scientists described in the Inside Your Turf column in GCM’s September issue.
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