The latest in tests and trials
Sports field managers across North America are becoming bolder in their experimentation with the types of turf they use on their fields. In many areas, they’re pushing the boundaries of cool-season and warm-season grasses far beyond traditional limits to find the combinations that work best under their specific environmental conditions and field use schedules. As outdoor sports programs push for on-field time earlier and later in the season, turf management is becoming more about fitting optimum turf growth patterns with when and how fields are used.
A major part of this progressive outlook is the testing data available through the National Turfgrass Evaluation Program (NTEP) and the cooperators who conduct the on-site testing. As noted on the Web site www.ntep.org, the NTEP was “designed to develop and coordinate uniform evaluation trials of turfgrass varieties and promising selections in the U.S. and Canada.”
On the site, sports field managers can view the entries submitted for the trials within each category of grasses, determine the sites where the trials take place and the university personnel associated with those sites. With a range of geographic locations serving as trial sites, the performance of specific cultivars can be compared for a broad overview under various conditions and under more region-specific conditions.
Single trait-specific testing
Highlights of the NTEP policy committee meeting this past February point to a new area, single trait-specific testing, that is targeted to identified turf management challenges. The two specific traits considered for testing are concerns for sports field managers: drought tolerance and traffic tolerance.
According to the highlights report, “NTEP will sponsor short-term, single trait trials that will evaluate more than one species, mixtures and blends. The first trait to be tested will be drought tolerance.”
NTEP has scheduled both of these single trait-specific trials for establishment in the fall of 2009. Advisory committees are to be formed to develop the parameters and details for each of these trials.
University turf specialists are valuable to the research equation. Along with their own research, they often become the official (or unofficial) partners, or the advisors, in the testing by individuals of different grasses and combinations of grasses on their own facilities. These university personnel frequently are the conduit for helping spread the news of projects in process and changes in turfgrass varieties and turf management techniques regionally and nationally.
Pam Sherratt, the Ohio State University sports turf extension specialist, notes that during the fall of 2007, overseeding in the Midwest with perennial ryegrass was successful in restoring fields to play-worthy condition in a relatively short time following the impact of the drought on turf wear. With little or no access to supplemental water, the existing turf had limited ability to recuperate from use. The cooler temperatures and natural rainfall, combined with a lessening of water-use restrictions in some areas, were instrumental to that success.
Sherratt noted that the OSU turf plots were hit with several diseases during the late spring and summer last year, but by reseeding in the fall, the new seedlings took over and restored the plots without treatment with control products.
Though OSU was not one of the participants in the NTEP tall fescue trails, Sherratt has been tracking the reports on the new improved cultivars, which are performing well in testing, and hopes to establish some test plots for OSU later this year. She says, “Originally, we didn’t trial them for sports field use because of the bunch grass growth pattern, but under typical use, there are few fields that don’t need overseeding. It’s needed for the bluegrass fields once they’re compacted. It’s more difficult to establish a straight bluegrass field from seed and it needs more irrigation, fertilization and mowing to avoid dandelion and clover infestation in the spring than a mixture of tall fescue, bluegrass and perennial ryegrass. A mix heavier on the tall fescue could prove to be a good choice, especially for the parks and recreation fields that get more use during the summer months.”
Pushing the climate zone
Brad Fresenburg, extension/ research associate for the University of Missouri at Columbia, notes that there is an increase in the use of cold-tolerant bermudagrass varieties on athletic fields in the southern two-thirds of the state, basically the area below Interstate 70. Currently, more fields are going with Riviera than Yukon, but both are used. A seeded cultivar that was listed as SWI-1012 in the NTEP trials is supposed to be a little more cold-tolerant and also should fit into that range. According to Fresenburg, it will be incorporated in the university’s ongoing warm-season turfgrass comparison area, a section of independent testing they are continuing to work with beyond the NTEP trials.
Sherratt noted that the Riviera in the OSU research plots goes dormant in mid-October and doesn’t come out of dormancy until mid to late May. She says, “Whether you seed, sprig or sod in the spring, you will be playing on juvenile turf in the fall.”
As those in the transition zone know, managing cool and warm-season turf on the same field is more challenging than dealing with either alone. A clear understanding of agronomics is essential. Fresenburg says that the question with any combination of cool and warm-season grasses is how you manage it: for the warm or for the cool? The types of varieties are also critical.
In the colder areas, the bermuda will take nearly constant overseeding with perennial ryegrass earlier in the fall. A cool spring will keep the bermuda from breaking dormancy until late in the spring season. That puts a lot of wear on the dormant bermuda during several months of active growth for the perennial ryegrass, which will predictably lead to a difficult transition back to bermuda for the summer months. OSU is continuing overseeding studies with the annual and transitional ryegrasses that would make the transition back to bermuda easier.
Sherratt reports that they have tested the theory of seeding bermudagrass into a combination bluegrass/perennial ryegrass field. She says, “The results were disappointing. We worked on a field that had a lot of bare patches of soil in the spring, anticipating the bermuda would take hold and fill in like an overseeding of perennial ryegrass or a bluegrass/perennial ryegrass combination. It only filled in partially, with small patches that did well, while other areas didn’t develop at all. Under similar conditions, the cool-season grass overseeding performed well. Poa annua infiltrations in similar conditions take hold so well they need to be sprayed out. The bermuda that had established went dormant in the fall and didn’t survive the winter.”
Part of Fresenburg’s testing area is a baseball infield. He says, “We have tried a number of different bermudas within the infield diamond and a blend of bluegrasses on the aprons. Though the bermuda here has done well, we still have concerns about winter injury.”
Both Sherratt and Fresenburg say they’ve seen some slow green-up with cool springs and some early green-up followed by late-season cold, often with snow or ice.
Fresenburg says, “Be patient if you’re pushing the climate zone, especially if you’ve used seeded bermuda. Let the bermuda get green before applying a preemergent. Those who put out Barricade early last spring, before winterkill became evident, couldn’t reseed for six months. Bermuda won’t green up until soil temperatures get into the 60s and 70s, the same range for the start for crabgrass. Wait to assess bermuda survival to keep that seeding option open. Dimension, applied a bit later, will take care of crabgrass even at the one to two-leaf stage, and still be a preemergent for the weeds that haven’t started.”
The cold-tolerant bermudas may be a good option for the parks and recreation fields and the athletic associations that have a lot of use in the summer. For the high school fields that get a lot more use in the spring and fall, cool-season grasses may be a better choice.
Dr. Gil Landry, coordinator for the Center for Urban Agriculture for the University of Georgia, points to water issues as the primary turfgrass management concern within the state and across much of the nation. In Georgia, stringent water restrictions are affecting the entire green industry. Landry says, “Sports fields and facilities have become a little more proactive in trying to explain what athletic fields and park systems mean to the community and why they should be considered an equal partner in the use of water.”
Landry says that many facilities have developed guidelines to rotate fields more frequently, to reduce the number of events on fields and, if drought conditions were to continue with no ability to irrigate, to take fields out of play. User groups were notified that any of these actions might occur depending on field conditions.
Management practices focus on trying to anticipate what conditions might occur and act in anticipation of them with adjustments such as raising the mowing height and lowering the level of nitrogen.
As the drought conditions persisted in 2007, local water authorities made rulings for their communities that were even more stringent than the statewide water restrictions, making it difficult for those operating in multiple communities to keep abreast of the changes and adhere to them.
Because water use will continue to be an issue for the foreseeable future, sports field managers must continue their documentation and conservation efforts.
Another hot topic affecting the turf industry is IPM and sustainable turf, organics and pesticide use. Sherratt reports on discussing this issue with colleagues and turf managers in Ontario, during a speaking engagement there. With Ontario now “pesticide free,” many athletic fields are filled with clover and dandelions, along with other weeds, but the implications of these conditions seem to not be understood by the public. The fields are perceived as “safer” for the athletes than the use of control products. Sherratt says that several school districts in Ohio are banning pesticides and mandating that only organic fertilizers be used on play areas.
Reasoned explanations too often lose the battle against biased opinions, especially when the fear factor is introduced. Thus, the need for sports field managers to develop and follow IPM and best management practices; document all of the steps involved; and be proactive in explaining what they do, why they do it and what it accomplishes.
The author is a contributing editor for SportsField Management.