A study by the Texas Transportation Institute (TTI) looked at the best mix of grasses to use on highway roadsides with an eye toward native seed varieties and the stresses and hazards that roadside plantings encounter. Ground preparations for paving projects often make the soil inhospitable to natives that rely on re-seeding in natural cycles, and highway rights of way must be mowed at least three times a year, which can interfere with growing cycles. Test plots were planted, and soil samples were analysed to see how the existing seed mix could be amended for a more native approach. One test plot was mowed at the same frequency and height as the Texas Department of Transportation (TxDOT) requires. Grass strips were also studies for their ability to act as filters to catch sediment from highway runoff. Swales, which are shallow depressions that carry water mainly during storms, can be planted with grass and used to filter out toxic and other pollutants. The article provides a chart with terminology and some basic facts about soil and vegetation research.
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