Which species is right for your field?
What kind of grass should be growing on my fields? Sounds simple at first, but when you dig deep, the decision is affected by many factors. As a sports turf manager, the task at hand is to sift through the various options and match up the attributes of the turf species with the specific features and limitations of the facility. This is not an easy endeavor; however, making the right choice could save time, money and effort down the road.
The extent of usage will affect turf species selection.
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In a way, turfgrass selection is much like buying a car. In that endeavor, lots of specifics, features, options, alterations and localized information need to be considered to drive the best fit off the lot. The same process is appropriate for choosing the most suitable grass or grass mixture.
Factors to consider
A needs assessment may be the most helpful place to start with the turf selection process. The following factors can greatly affect turf species selection. No one species is best in all categories.
Traffic – Without a doubt, traffic is one of the most important considerations in sports turf. A 300-pound lineman can really tear up a field, especially when it’s wet and he’s angry. The turf species that you choose must be traffic tolerant. Tall fescue, bermuda and perennial ryegrass top the list of options.
Mowing height preference – Each species has a preferred range in terms of mowing height at which they perform best. Creeping bentgrass and bermudagrass tolerate the lowest height of cut, while tall fescue prefers the highest. Ryegrass, bluegrass and zoysia are intermediate.
Game usage – Somewhat related to traffic tolerance, usage is dictated by the frequency of games and practices. The caveat of season of year is also to be considered, especially if some fields are used lightly in some seasons.
Nongame events – Concerts, skating practice and parking are tough on sports turf. In many situations, replacement is written into the contract for the event; however, it’s tough to “un-compact” a field. Obviously, the fewer the nongame events, the better.
Overall usage – In addition to events, the number of teams that use the facility on a regular basis, usage during times outside the season of play, and band practices and competitions add to the need for a wear-resistant species. Tournament play can be a wild card factor as well, especially when scheduled at the last minute. Traffic damage can be mitigated slightly when the owner of the facility understands the need to take fields out of play for renovation, recovery or extensive cultivation.
Climate – Defined as the atmospheric conditions experienced over time in a particular location, climate can have a dramatic effect on turfgrass species selection. Warm-season turfs, such as bermuda and zoysia, have been used farther north in the past few years, as transition zone turf managers are looking for density and durability for sports fields. However, depending on the harshness of winter conditions, the decision to experiment with warm-season turfs may need to be reconsidered. Likewise, cool-season turfs can wither in the heat of southern summers, failing to provide a durable playing surface.
Budget – Like it or not, available funds may be one of the biggest influencers of the turfgrass species and cultivar decision. Experienced turf managers know that it’s best to avoid underestimating the cost of maintaining a field throughout a season or calendar year. Fortunately, computer software makes the budgeting process a bit easier than it was 20 to 25 years ago.
In some cases, it may be necessary to incorporate an overage or estimated rise in the price of various categories of inputs, such as fertilizers and pesticides, that are required to maintain certain turf species. Also, the price of seed itself rises and falls, depending on the harvest conditions and costs of production for the grower. Fluctuations for sod are no different.
General species considerations
Kentucky bluegrass is the principal cool-season recreation turfgrass. Seeds germinate slowly (14 to 28 days), but it can form a dense turf and recuperate well from injury because the mature plant produces rhizomes that give rise to additional bluegrass plants. Acceptable turf cover after seeding may require six to nine months.
Perennial ryegrass can develop a high-quality turf and has rapid seed germination (three to five days). Although the grass grows in bunches, it can create a thick turf due to its heavy tillering. It has lower cold and disease tolerance than Kentucky bluegrass.
Tall fescue germinates within five to seven days and is tolerant of low fertility, shade and wear. Tall fescue is a bunch-type and can be mixed effectively with Kentucky bluegrass (90 to 95 percent tall fescue). It is not as cold tolerant as Kentucky bluegrass and has moderate disease tolerance. However, it is susceptible to brown patch during the hot, humid months of summer.
The desired mowing height often influences species selection.
PHOTOS BY JOHN C. FECH, UNL, UNLESS OTHERWISE NOTED.
Bermudagrass is normally established using sprigs or sod, but seeded varieties are also available. If established in May, with proper management fields may be ready as early as September. This grass is very wear tolerant during the summer and early fall, but can be severely damaged with late-season use. A reel mower should be used for best appearance.
Considering the environmental conditions of the past couple years, turfgrasses and how they respond to drought may be a significant factor when selecting grasses this season. It is important to understand that most grasses with drought-resistant characteristics are usually considered either drought tolerant or drought avoidant.
Bermudagrass provides the ability to recover from injury if treated with good best management practices.
Drought-tolerant grasses have the ability to draw more water into the cell at the onset of drought and can tolerate dehydration fairly well. They often possess excellent dormancy mechanisms and have a good ability to recover from dormancy. Assuming they survive the stressed conditions, these grasses usually green up within a couple of weeks once the drought period has ended. Species considered drought tolerant are Kentucky bluegrass, bermudagrass, buffalograss and zoysiagrass.
Drought-avoidant grasses normally depend on their deep, extensive root systems to maintain growth when drought stressed. They also have a high ratio of roots to shoots and demonstrate xeromorphic characteristics, such as leaf rolling, hairy leaves and thick cuticles, to minimize water loss. Drawbacks to drought-avoidant grasses are that they may not possess good dormancy mechanisms, and they have poor recovery from extended severe drought.
Essentially, these grasses will continue to grow until they run out of water, and then they usually die. Compacted soils will also harshly impact drought-avoidant grasses, because the rootzone that they rely on for water has been reduced to the point that it can no longer provide it adequately. However, these grasses show few signs of wilt and respond well to supplemental irrigation, so they are often considered quite desirable for turfgrass situations. Species considered drought avoidant are tall fescue, perennial ryegrass and bermudagrass.
If hot, dry conditions persist for extended periods, as in the arid Southwest, cool-season grasses may be more favorable than perceived. The lower humidity will allow the grasses to benefit from transpirational cooling, and the relatively cooler nights may reduce nighttime respiration rates, resulting in a more positive energy balance within the plant. Disease pressure would also be less than in humid areas.
Fine-tune with cultivars
The National Turfgrass Evaluation Program (NTEP) provides useful information to use when making a decision about turfgrass selection. Two parts of the NTEP are particularly helpful. First, the program is nationwide, with evaluation sites in every region of the country. Use the site closest to your facility when gathering specifics on the performance of each species and cultivar under consideration. In some cases, the facility may be equidistant to two or more testing sites; naturally, all of these should be investigated and compared.
The second part is the specific factors that have been rated for each species and cultivar. Color, density, disease resistance, spring green-up and overall quality are commonly rated for each. This information is extremely useful, as cultivars are compared, and much more important than initial cost of the seed. These performance factors are difficult to overcome as opposed to simply paying a bit more for cultivar A versus cultivar B.
If you’re still having trouble deciding which grass is best for your situation, contact your local extension specialist, college or university representative or sports turf manager.
John Fech is an extension educator specializing in turf and ornamentals at the University of Nebraska-Lincoln. Brad Jakubowski is an instructor at Doane College.