SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/162108
FieldScience OVERSEEDED species competing with bermuda during spring transition. UP-CLOSE VIEW of a ryegrass seed germinating. mediate" ryegrasses. The ryegrasses have a large seed size, with significant endosperm (food reserves), which helps them germinate fast and mature quickly when planted under ideal conditions. Generally, most managers select and plant good quality perennial ryegrasses for winter overseeding, especially where they plan to chemically remove the overseeding. There are, however, alternatives that can be considered. Annual ryegrass is one of the options among the ryegrasses and appears to be attractive from a price point, 25-40% less than a high quality perennial ryegrass. Most annual ryegrasses tend to form a lower quality turf than the perennial ryegrasses, even when well established. Many people do not like the lightgreen/yellow-green color and the turf may be prone to becoming "stemmy" with poor mowing quality/leaf shredding. Lastly, annual ryegrass is sensitive to harsh winter conditions and will die quickly with the onset of summer heat, making it somewhat unreliable. Although breeders continue to improve and advance this grass, it may best be left for use in places where appearance is not paramount like utility lawns. Some researchers have been evaluating the tetraploid ryegrasses for overseeding with some success. These ryegrasses are sometimes referred to as "intermediate" ryegrasses and have turf quality characteristics similar to the perennial ryegrasses but their heat tolerance is not very good, somewhat similar to an annual ryegrass. This lack of heat tolerance helps as the turf stand transitions back to bermudagrass during late-spring without the need for chemical transitioning. What about other species and options? Turf breeders continue to advance all species with the help of feedback from turf managers and desirable characteristics. In some parts of the country I have heard of managers exploring the incorporation of Kentucky bluegrass into their bermudagrass. The goal I am told, is to create a polystand of warm and cool-season spreading, self-repairing grasses that would ebb and flow throughout the growing season. This mixture of bermudagrass and bluegrass might allow for greater intense use across all seasons, spring, summer, autumn, while providing moderate green color all season without a need to overseed/interseed. This technique has not been well evaluated in research trials and it is possible that over a period of years the turf could become very patchy due to segregation. This approach may have some merit where appearance is not paramount and is not a suggested option for stadium fields. The turf-type tall fescues are another species that has not been well explored, particularly the very narrow leaved ones. The seed size of tall fescue is similar to perennial ryegrass and germination, emergence and establishment is about the same, but ever so slightly slower. Further, with some of the new turf-type tall fescues the visual (color/density) and mowing characteristics are similar to perennial ryegrass or a Kentucky bluegrass. One advantage to using tall fescue is it is not quite as susceptible to gray leaf spot compared to perennial ryegrass. Tall fescue does, however, have very good heat and drought tolerance and would need to be chemically removed the following spring. The final point I should make is to remember, like anything, you get what you pay for! Purchasing a higher quality ryegrass that germinates quickly and has good turf characteristics (color, leaf texture, density) would in most circumstances be preferred over a less expensive species that has poor seed quality. These less expensive, lower quality seed lots tend to have a greater potential for annual bluegrass (Poa annua L.) contamination and that introduces a whole group of other future problems. HOW MUCH SEED? If you look up published seeding rates for any grass species the values are normally based on the assumption that you will be seeding on bare soil with the intended purpose of an ornamental lawn, etc. As we all know athletic Figure 1 14 SportsTurf | September 2013 www.sportsturfonline.com