Developing Less Thirsty Turfgrasses
What the TWCA is doing to meet the water-use challenges facing turfgrass
Turfgrass pros vist the NexGen Turf Research location in Albany, Ore., to view turf plots subjected to drought stress.
Photos courtesy of NexGen Turf Research.
Fresh water is a limited resource. Urbanization and the need to produce food for a growing population are creating ever-greater demands for fresh water. Meanwhile, changing weather patterns that result in droughts are also putting more strain on water availability.
The Turfgrass Water Conservation Alliance (TWCA), a partnership between researchers and turfgrass seed suppliers, says that demand for water has gone up 300 percent in the last half-century. Furthermore, there seems to be little likelihood that this growing demand for water will abate. In addition, estimates are that between 2000 and 2025 population growth will mean a 22.43 percent decrease in the amount of water available per person. Both public opinion and regulatory action are creating a need for turfgrass professionals to address the issue of water resource use and to do their part to conserve precious water resources.
In response, the TWCA was formed to combat the threat of depleting water resources, with a concentration on non-agricultural land areas, including lawns, sports venues, recreation areas and other landscapes. The TWCA was formed as an unbiased, independent body, which evaluates the drought hardiness of new cultivars of turfgrass, and then educates consumers and landscapers about the availability of, and need for, such new cultivars.
The TWCA is an offshoot of activities by Kenneth Hignight, director of research for NexGen Turf Research, and others to find ways to lower water use in turfgrass cultivation and then to develop objective ways of measuring the savings afforded by the new cultivars.
"The key to it all is greenness. Consumers judge their lawns by the greenness of their grass, and want to turn on the water when a lawn looks off color. So any cultivar that stays green when drier has an advantage. Also prized are turfs that recover to green faster after drought relief," says Cale Bigelow, an associate professor of Agronomy at Purdue University in West Lafayette, Ind.
Hignight began his efforts in 1993, first concentrating on creating cultivars with deeper roots and then designing a test infrastructure that could measure low-water performance objectively. In 2002, he says, a presentation on digital imaging analysis by Doug Karcher, an assistant professor at the University of Arkansas, showed researchers a way to evaluate seed performance that was less subjective than the 1 to 9 rating scheme used by NTEP, the National Turfgrass Evaluation Program.
In the NTEP trials, cooperators at sites across the United States and Canada plant and evaluate plots of turfgrass of different species and cultivars and rate them on the scale for such characteristics as color, leaf texture, spring greenup and drought, to name a few. The higher the number, the better a particular grass is for each characteristic. As the ratings depend upon visual examination, they are highly subjective.
By contrast, digital imaging uses a lightbox to analyze digital photos, counting the ratio of pixels of green versus non-green. Turf can thus be more precisely evaluated for color and density, insists the TWCA.
Hignight says the formation of the TWCA enlisted seed companies such as Turf Merchants, Proseeds Marketing, Pennington and PureSeed Testing into the picture. This served to make the evaluations more affordable. Plus, in addition to the objective quantification allowed by digital analysis, the TWCA's independent Research Review Board acts as a third-party turfseed evaluator, meaning findings can be trusted to meet rigorous scientific standards.
Neither food nor fiber
Bigelow says that the turfgrass breeders wanted to get involved in water conservation efforts because turfgrass is an amenity, not used for food, fiber or fuel.
According to Crystal Fricker, president of PureSeed Testing, the industry's turfseed suppliers are now working together to develop low-water-use turfgrasses, some of the research spinning off of salinity trials. She notes that she and Hignight have been comparing notes and exchanging ideas. "It used to just be companies saying that they have this and that, and marketing what they claim are their advantages," she says. "But now we have independent third-party verification. It's not just a seed company saying 'We are the best.' We take our data and send it right to Mike Richardson and Doug Karcher at the University of Arkansas, and they use their expertise to analyze our data. I am not always even sure what we have until they look at it."
Hignight says it took a long time to work through the process. "Today, we can establish how the grass will look when there is a specific percentage of moisture left. In some cases, some grasses require as much as twice the amount of water to look the same," he explains.
The researchers are looking at Kentucky and Texas bluegrasses, as well as tall fescue, ryegrass and fine fescues. Genetic sources are important to determining water conservation characteristics, adds Hignight. The top performers of the Comparative Turfgrass Breeders Association represent a strong genetic sampling.
Bringing a new cultivar of turfgrass to market with traits such as drought resistance may take a decade. The process starts with selecting likely candidates and then evaluating them for several years in turf plots at various locations in the U.S. and Canada. Eventually, the performance of these grasses is reported on www.ntep.org.
"The top 3 to 5 percent have passed a tough test for drought resistance," says Hignight. "We have a good feel for it now. We have learned to crawl, and now we are starting to walk."
So far, TWCA members have conducted studies at sites in Arkansas, Oregon, Indiana, Virginia, North Carolina, California, Alberta and Ontario. Hoop houses open on all sides are used to control water availability. Grasses are given a season to become established then they are subjected to a thorough saturation and then an extended drought stress. Digital analysis can then be used to quantify the percentage of green turf cover. When the green turf cover this falls below 25 percent, the grasses are irrigated so that their recovery rates can be measured.
It is necessary to test in varied geographic areas due to differences in soil, topography and weather, explains Bigelow.
Fricker adds that the research has had its ups and downs in some locations, with rain and wind knocking down three of her protective structures.
"We have learned a lot," she says. "What we are finding is that in each species, we get a range of results, with good and bad in each, be it bluegrass, ryegrass, tall fescue and fine fescue. But there are exciting finds in each species. The fine fescues are the forgotten species as far as water usage, as well as shade performance. And some of the hard fescues have been amazing in how they stay green. We see great recovery and survival rates, too."
She adds that she and Hignight see similar trends among the varieties. "It is pretty technical, pretty data-intensive. And it takes a lot of travel," she says.
Eric Lyons, associate professor in the Department of Plant Agriculture, University of Guelph, Ontario, Canada, has just started research with TWCA on Kentucky bluegrass at the Canadian sites, in response to a bad drought that hit Canada in 2012. It was so bad in some locations that even deep-rooted trees were dying. Beyond drought resistance, turfgrass developed for the Canadian market must also be winter hardy, he adds.
"This is in response to a push from Canadian suppliers," he says. "They need to be able to provide a product for their customers. The Canadian Turfgrass Research Foundation is helping to fund the trials.
Lyons says that researchers are looking at the mechanisms that enable certain cultivars of turfgrass to perform well in spite of stressors, such as drought. "Turf breeders around the world want to know why they are performing well," he says. The answers, so far, point to deeper roots that can reach lower to access water and the ability of some grasses to alter the structures of their stomates to conserve what water they have.
Education comes next
But when it comes to maintaining green, healthy turfgrass with less water, plant genetics are just part of the equation, says Hignight. Management practices must improve, as well. These include soil factors such as soil preparation, being better able to measure and respond to evapotranspiration and advances in irrigation technology, itself.
"Genetics are foundational, but management technologies are key," he says. Ultimately, once the industry gets past evaluation, it comes down to communication on a large scale, says Hignight.
Lyons notes that much of the TWCA focus is aimed at homeowners that are concerned about the greenness of their lawns, with the message that they won't have to water as often.
"Water conservation is a big deal. We have urban water districts. High water use will deplete the cities. We can't keep using more water than is being re-supplied," says Lyons.
Adds Fricker, "We are setting up to get better, to get a certified-quality product. I like that the idea of raising the bar and bringing meaning to what the turfgrass industry does. We want to have a quality level the consumers and landscape pros can trust."
Initially, there was discussion about establishing a performance standard for turfgrass and calling it WaterStar, analogous to the Energy Star rating system for appliances. Instead, it was decided to use the term more as a brand or descriptor. The TWCA site lists TWCA-qualified cultivars.
"It's the potential for renovation, to introduce new grasses, while reducing water and power use and other inputs as well," says Bigelow. "We update our cars and clothes. Why not update our cultivars too for more efficiency?"
This benefits end-users and landscape pros as well as reducing water and other inputs can save time and money on maintenance, he adds.
Cindy Greenwald is a writer and editor that has been covering small business in print publications and online for more than 30 years. She lives and works in Cleveland, Ohio. Contact her at email@example.com.