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Warm-Season Turf for the Transition Zone
The "crabgrass belt" was what Dr. Ian Forbes, former agronomist at the Department of Agriculture, termed the transition zone (Forbes and Ferguson, 1948). The transition zone stretched from Kansas to Maryland without defined boundaries. Both cool-season and warm-season turfgrasses are present in this area due to the great variability in climate. Although many are present, few turfgrass species are well adapted to this challenging climate.
Turfgrass adaptation is primarily determined by temperature and moisture. Plants that are well adapted to a particular area can usually withstand high and low temperatures as well as wet and dry periods. Even though both cool-season and warm-season grasses grow in the transition zone, golf courses primarily have cool-season grasses such as annual bluegrass, Kentucky bluegrass, and perennial ryegrass on the fairways. Golf course superintendents in this region have a great deal of trouble maintaining cool-season grasses during the summer due to excessive heat, water requirements, disease pressure and golfer traffic. These grasses decline, causing poor golfing conditions in spite of superintendents spending countless hours and dollars to maintain acceptable playing surfaces.
However, there is a potential solution: bermudagrass and zoysiagrass. Bermudagrass (Cynodon spp.) and zoysiagrass (Zoysia japonica) both produce excellent fairway turf in the transition zone. During summer months in the transition zone, bermudagrass and zoysiagrass are actively growing and during the cool periods of the year, they enter winter dormancy. Both grasses are cost effective and environmentally friendly to maintain.
Bermudagrass
Bermudagrass is an introduced grass species to the United States. Originating in Africa, bermudagrass is a warm-season turfgrass species that is well suited for golf course greens, tees, fairways, and rough. Two species of bermudagrass are used on golf courses, hybrid bermudagrass (Cynodon dactylon x. C. transvaalensis) and common bermudagrass (Cynodon dactylon). Establishment of common bermudagrass is by seed, whereas hybrid bermudagrass must be established by sodding or sprigging. Once established, bermudagrass creates an aggressive turf with high shoot densities (Beard, 1973).
Bermudagrass is best adapted to southern regions of the transition zone, the warm arid zone, and the warm humid zone. When bermudagrass is planted in the transition zone, it can be seriously thinned by low temperature kill during the first year of establishment (Philley and Krans, 1998) and again every four to five years depending on the severity of the winter (Anonymous, 1960).
Zoysiagrass
Zoysiagrass is also an introduced grass species to the United States. Zoysiagrass, named after Austrian botanist Karl Von Zois, was introduced into the United States in the early 1900s (McDonald and Copeland, 1997). Originating in East Asian coastal areas, zoysiagrass is a warm-season turfgrass species well suited for golf course fairways, tees and bunker faces. Once established, zoysiagrass creates a dense, high quality turf (Beard, 1973).
Zoysiagrass performs especially well on golf course fairways and finds its greatest niche in the transition zone. Unlike bermudagrass, dormant zoysiagrass fairways remain highly playable for golfers. Zoysiagrass has excellent cold tolerance and is the most winter tolerant of the warm-season grasses adapted to the transition zone (Rogers et al., 1977; Turgeon, 2002).
Advantages
Bermudagrass and zoysiagrass are commonly used in the transition zone due to difficulty in the management of cool-season turfgrasses. Bermudagrass and zoysiagrass require fewer inputs than do most cool-season fairway turfs making them less expensive and more environmentally friendly to maintain (Williams, 2001). The following section outlines the cost of maintenance on a cool-season fairway versus a warm-season fairway in the transition zone.
Fertilization
When compared to warm-season grasses, cool-season grasses require more N/1000ft2 per year in the transition zone. This increase in fertility is due to a longer growing season of cool-season grasses. Typically, perennial ryegrass requires between 0.4-1.0 pounds of nitrogen (N) per growing month depending on the intensity of the culture, which equates to 4 lbs. of N/1000ft2 per year in the transition zone (Beard, 1973). On the other hand bermudagrass and zoysiagrass in the transition zone require between 0.5-1.5 pounds of nitrogen (N) per growing month depending on the intensity of the culture, which equates to about 3 lbs. of N/1000ft2 per year for bermudagrass and only 2 lbs. of N/1000ft2 per year for zoysiagrass (Beard, 1973)
While cool-season turfs must be fertilized with slow-release fertilizers at certain times during the year because of agronomic reasons and potential for fertilizer burn, quick release fertilizers are often used on the warm-season grasses due to their low burn potential. Since quick release fertilizers are cheaper than slow-release fertilizers, the cost of fertilization can potentially drop with the use of warm-season grasses. However, superintendents may choose to use a slow-release fertilizer on their warm-season fairways in the transition zone in order to provide a slow feed and reduce the potential for fertilizer burn at the interface with a cool-season rough (Healey, 2002). Regardless of strategy, warm-season grasses require less annual fertility in the transition zone (see Table 1).
Fungicides
Currently, the only major diseases that affect bermudagrass in the transition zone are spring dead spot (ophiosphaerella spp.) and dollar spot (Sclerotinia homeocarpa), while zoysiagrass only suffers from Rhizoctonia large patch disease (Rhizoctonia solani) (Anderson et al., 2002; Anonymous, 2002; Tisserat, 2002). Conversely, cool-season grasses can be affected by numerous diseases including anthracnose (Colletotrichum graminicola), dollar spot (Sclerotinia homeocarpa), gray leaf spot (Pyricularia grisea), pythium blight (Pythium spp.), Rhizoctonia blight (Rhizoctonia solani), and summer patch (Magnaporthe poae) (Couch, 1995). Disease susceptibility drives up maintenance costs and reduces environmental soundness of cool-season grasses.
Insecticides
Bermudagrass and zoysiagrass in the transition zone are less susceptible to insect pests compared to cool-season turf. Most of the insect pests that affect bermudagrass and zoysiagrass are located in the warm-arid regions of the country, south of the transition zone. The armyworm (bermuda) and the hunting billbug (zoysia) are capable of causing damage (Potter, 1998). However, few reports of damage to warm-season turf are reported in the transition zone (Bullerdick, 2002; Healey, 2002; Lampkins, 2002; Robbeloth, 2002; Will, 2002). Unlike cool-season turfs, which are often damaged by white grubs and other insect pests, bermudagrass and zoysiagrass suffer little damage in the transition zone.
Herbicides
Whether growing cool-season or warm-season turf, every golf course has occasional weed problems. Most superintendents in the transition zone will use pre-emergence herbicides for the control of annual grassy weeds on both cool-season and warm-season fairways. The dense cover of zoysiagrass and bermudagrass may help reduce weed populations, and in general the weed control budget of a warm-season turf will be slightly less than a cool-season stand. Perennial and winter-annual weeds are controlled on dormant bermudagrass or zoysiagrass with a single application of a non-selective herbicide in the winter. On the other hand, on cool-season turfs perennial weeds and winter-annual weeds are often controlled in two separate applications. This extra application and the more expensive post-emergent selective herbicides increases weed control costs in cool-season turf compared to warm-season turf.
Irrigation
Bermudagrass and zoysiagrass have excellent heat and drought tolerance when compared to cool-season grasses (Christians, 1998). Bermudagrass and zoysiagrass are better adapted to the hot, humid summers in the transition zone than cool-season turfs. Using either of these grasses on golf course fairways in the transition zone will reduce irrigation requirements resulting on lower irrigation costs (Biran et al., 1981).
Mowing
Mowing fairways take a considerable amount of time. Usually, superintendents utilize their best employees for this task. The amount of time spent on fairway mowing varies by species. Time spent mowing fairways from greatest to least is annual bluegrass/perennial ryegrass, bermudagrass, and zoysiagrass. Annual bluegrass/perennial ryegrass fairways usually more total mowing because they actively grow from March to November. Bermudagrass requires a great deal of mowing during the summer months but will only grow from May to October in the transition zone. Zoysiagrass is the slowest grass of the bunch, and may only need mowing two to three times per week from May to October.
Wear Tolerance
Another benefit of bermudagrass and zoysiagrass use in the transition zone is wear tolerance. Since bermudagrass and zoysiagrass are warm-season turfgrasses, they are actively growing during the greatest period of golfer activity and offer better wear tolerance than cool-season species (Youngner, 1961). In fact, most courses with bermudagrass or zoysiagrass fairways actually instruct the golfers to keep golf carts in the fairway and out of cool-season roughs during the summers. In review, the benefits of bermudagrass and zoysiagrass include reduced fertilization, reduced fungicide and insecticide costs, reduced irrigation requirements, reduced annual mowing, and increased wear tolerance (see Table 3).
Disadvantages
The disadvantages of warm-season species compared to cool-season species in the transition zone are few, but include winterkill potential, winter color, thatch, and establishment costs (see Table 3).
Winterkill potential
Winter hardiness is a concern of most superintendents in the transition zone. Bermudagrass is less winter hardy than zoysiagrass and can potentially winter kill every few years (Rogers et al., 1977). Zoysiagrass, although more cold tolerant than bermudagrass, can also winterkill in the transition zone. Increasing potassium fertility may increase winter hardiness (Beard, 1973), but the best cultural practice for decreasing winter damage is to remove traffic from fairways during the winter (Reicher, 2002). Despite possible loss of warm-season turfs every four or five years, annual ryegrass/perennial ryegrass fairways face this risk almost every summer.
Winter Color
Another negative aspect of warm-season turf is its tan winter color during dormancy. Zoysiagrass remains very playable in the winter months despite its dormancy with stiff leaves that produce a great lie all year long. However, this is not the case with bermudagrass. Bermudagrass loses much of its canopy during the winter months and is often worn down to bare soil. In order to maintain excellent playing conditions all year, bermudagrass may need to be over-seeded with perennial ryegrass. This is a popular practice in southern regions of the United States but is avoided by most superintendents in the transition zone due to increased cost and delayed spring transition.
Thatch
Due to the stoloniferous and rhizomatous habit of bermudagrass and zoysiagrass, these species may require more frequent aerification to decrease thatch build-up. More frequent aerification may require new equipment and will increase labor costs. However, aerification will not only reduce thatch, but also reduce disease in warm-season fairways (Anderson et al., 2002; Tisserat, 2002).
Establishment
A primary drawback to the warm-season grasses is establishment cost. Bermudagrass is relatively inexpensive to establish, either by sprigging or seeding, but is more expensive to solid-sod. Zoysiagrass is generally more expensive than bermudagrass to establish. Zoysiagrass can be established by seeding, sprigging, strip-sodding and solid-sodding. All methods can be effective in the long-term, but certain methods will be much more advantageous in the short term (see Table 2).
Traditionally, warm-season grasses have been established vegetatively, not by seeding. Vegetative establishment is expensive relative to seeding. For instance, sprigging bermudagrass is estimated at approximately $1000/acre and solid-sodding zoysiagrass may cost $15,000/acre whereas seeding cost for bermudagrass and zoysiagrass are less than $1,250 (Williams, 2001; Will, 2002). Bermudagrass and zoysiagrass establishment by seed is not only more cost effective than vegetative establishment but is also less labor intensive.
Dr. Dave Williams, at the University of Kentucky, is one of the principal investigators of seeded warm-season grasses. According to Williams, although seeded bermudagrass and zoysiagrass have not been frequently used on golf course fairways in the past, new varieties are making seeding more popular due to the improvements in texture, color, growth habit, and winter hardiness (2001). National Turfgrass Evaluation Program (NTEP) data show that several seeded bermudagrass and seeded zoysiagrass cultivars display characteristics similar to vegetative varieties (2001; Williams, 2001). NTEP tests in Indiana, Kansas, Kentucky, Maryland, Missouri, Southern Illinois, and Virginia have identified seeded bermudagrass and zoysiagrass cultivars that will perform well in the transition zone (Williams, 2001).
Despite the data on seeded varieties, many superintendents still use vegetative methods for establishment. Researchers at Purdue University, the University of Kentucky, Kansas State University, and the University of Arkansas are currently working on defining the best methods for seeded warm-season grasses. Although few superintendents are currently using seeded bermudagrass or zoysiagrass, the data is convincing, and superintendents may ultimately begin using seeded varieties.
Case Studies
Many golf courses across the transition zone have already established either bermudagrass or zoysiagrass on their golf course fairways. The following section details three superintendents and their experiences with establishing warm-season fairways in the transition zone.
Valley View Golf Club, Floyds Knobs, Indiana
In the fall of 1999, Valley View Golf Club superintendent, Kelly Robbeloth, and the board of directors decided it was time for a change. They decided to convert the existing perennial ryegrass fairways to bermudagrass because of the high maintenance budget of the perennial ryegrass fairways. Valley View Golf Club, located in southern Indiana near the Ohio River, is an area that stays hot and humid during the transition zone summers. Kelly had problems maintaining his fairways due to lack of an adequate water source and outbreaks of gray leaf spot. Valley View wanted a turfgrass that was better adapted to the summer heat and humidity.
In the summer of 2003, 30 acres of fairway turf along with 15 acres of green banks and intermediate rough were sprigged with 'Midland' bermudagrass after a non-selective herbicide application. The areas completely filled-in and the course were reopened by the end of the summer. Kelly and the board of directors were very please with the results. The only complaints came from senior golfers who had a difficult time plying from the bermudagrass rough. With the new bermudagrass, Kelly accomplished one of the club's goals of reducing water use. In the summer of 2001, he did not have to turn on the irrigation system once. According to Kelly, the only major drawback to bermudagrass is mowing. The new bermudagrass fairways hold their morning dew longer, forcing Kelly and his crew to mow later in the day during high golfer activity. In addition, the rapid growth rate if bermudagrass keeps them busy mowing and blowing off fairways four days a week.
Despite more mowing, the cost of establishment was well worth it. Kelly kept track of the expenditures during the renovation process. The cost of spriggs, sod, (zoysiagrass around the greens to reduce bermudagrass encroachment), chemicals, and fertilizers during the establishment process totaled $98,000. One year after the renovation was complete; Kelly compared the 1999 perennial ryegrass budget of $133,000 with his 2001 bermudagrass budget of only $49,000 and found an annual savings of $84,000. When asked what he might do different if he were to do it over again, he said he might consider using seeded zoysiagrass, but he was very happy with the bermudagrass (Robbeloth, 2002).
Bloomington Country Club, Bloomington, Indiana
Bloomington Country Club, in Bloomington, Indiana, is located at the northern edge of the transition zone. When Bruce Bellerdick, CGCS, first took the job at Bloomington Country Club in 1990 he was maintaining 18 holes of annual bluegrass/perennial ryegrass fairways. These fairways were situated in heavy clay soils, and irrigated by an inadequate system with purchased city water. Soon after taking the job he quickly learned of the memberships desire to implement zoysiagrass fairways. After discussing the potential cost savings with Bruce, the committee decided on zoysiagrass.
The committee wasted no time in getting started. In 1991, the back nine was solid-sodded with ‘Meyer’ zoysiagrass transported from Arkansas. While the conversion was being completed on the back-nine, the members continued to play on the front-nine until it was renovated later in 1992. In all, 20 acres of zoysiagrass was planted at Bloomington Country Club. After the project was completed, the only complaint from the golfers was that it was more difficult to hit the ball off the fairway when playing other golf courses.
When I asked Bruce how he felt about the zoysiagrass, he said, “We don’t have enough of it!” Bruce felt the only major drawback was that zoysiagrass was difficult to mow and difficult to keep the mowers adjusted properly to cut the stiff leaf blades of zoysiagrass. Rhizoctonia large patch was also one of his concerns. However with spot treatment, he estimates that he only spends about 2,000 dollars a year controlling this disease. Bruce also raised the fairway mowing height from 1/2 to 5/8 of an inch and in doing so he observed a decrease in the severity of the disease. When asked if he would do anything differently, Bruce answered, “I wouldn’t do anything different.” Due to increased play, increased revenue from 50 new members, and decreased costs, he calculated that the cost of establishment was recuperated in only two and a half years (Bullerdick, 2002).
McDonald Golf Course, Evansville, Indiana
Evansville, Indiana, often termed the tri-state area, is located in the tip of Indiana between Southern Illinois and Kentucky. The McDonald Golf Course, located in Evansville, IN, is a nine-hole municipal golf course. Like most municipal golf courses the budget does not allow for high expenditures. In 2000, Bill Lampkins, superintendent of McDonald Golf Course, decided to give zoysiagrass a try.
In 1999, the fifth hole at McDonald Golf Course was redesigned to improve drainage, add a pond, and change the layout of the hole. The new 580-yard par 5 was then seeded in the fall with perennial ryegrass to provide some coverage. That next summer Bill decided to try zoysiagrass. Since his budget was limited, he decided to strip-sod ‘Meyer’ zoysiagrass into the new fifth fairway instead of solid-sodding. The sod was stripped into the existing perennial ryegrass fairways. Since the installation, he has stopped applying any fungicides to the fairway to give zoysiagrass a better chance to spread and fill in between the strips. After two years Bill plans on spraying an application of a non-selective herbicide on the dormant zoysiagrass in order to kill the remaining ryegrass and allow the zoysiagrass to fill in the remaining areas.
The only major downside of zoysiagrass according to Bill is the increased need of fairway aerification to prevent thatch accumulation. When asked how golfers felt about the strip-sodded fairway, Bill said, “They don’t seem to mind, they just roll their ball onto the lie they want.” The long-term plan at McDonald Golf Course is to strip sod one or two fairways a year until they are all done. As he finishes the remaining holes, Bill said he would not do much different except to make sure the fairway contours are outlined carefully before zoysiagrass installation. Although the fifth hole is the only current hole with zoysiagrass, Bill estimates that once the project is done he will save about $30,000 a year on his 13 acres of fairways (Lampkins, 2002).
Summary
These are only a few examples of bermudagrass and zoysiagrass in the transition zone. The best source of information on their management and establishment is the superintendents who manage these courses form day to day. Whether a golf course is public or private, everyone can enjoy the long-term cost savings, excellent playability, and environmentally friendliness of bermudagrass or zoysiagrass in the transition zone.
List of References
1. Aderson, M., A. Guenzi, D. Martin, C. Taliaferro,
and N. Tisserat. 2002. Spring Dead Spot: A Major Bermudagrass Disease. USGA
Green Section Record 40(1):21-23.
2. Anonymous. 1960. Winter kill problems with bermudagrass. Mid-Continent
Turfletter, USGA Green Section No. 3. pp. 1-2.
3. Anonymous. Feb. 27, 2002. Dollar spot of Bermudagrass.(http://msucares.com).
4. Beard, J.B. 1973. Turfgrass Science and Culture. Prentice Hall, Inc. Englewood
Cliffs, N.J.
5. Biran, I., B. Bravado, I. Bushkin-Harav, E. Rawitz, 1981. Water consumption
and growth rate of 11 turfgrasses as affected by mowing height, irrigation
frequency, and soil moisture. Agronomy Journal 73:85-90.
6. Bullerdick, B. 2002. Personal interview. Superintendent at Bloomington
Country Club. Bloomington, Indiana.
7. Couch, H.B. 1995 Diseases of Turfgrass. Krieger Publishing Co., Malibar,
Florida.
8. Christians, N.E. 1998. Fundamentals of Turfgrass Management. Ann Arbor
Press, Chelsea, Michigan.
9. Forbes, I.J. and Ferguson M.S. 1948. Effect of strain differences, seed
treatment, and planting depth on seed germination of Zoysia spp. Agronomy
Journal 40:725-732.
10. Healey, C. 2002. Personal interview. Horizon Construction, Evansville,
Indiana.
11. Lampkins, B. 2002. Personal interview. Superintendent at McDonald Golf
Course, Evansville, Indiana.
12. McDonald, M.B. and L.O. Copeland. 1997. Seed production: principle and
practice. Chapman Hall, New York.
13. National Turfgrass
Evaluation Program (NTEP). Feb. 18, 2002.
14. Philley, W.H., J.V. Krans. 1998. Turf performance of seeded bermudagrass
cultivars. Golf Course Management 66(11):62-66.
15. Potter, D. 1998. Destructive Turfgrass Insects: Biology, Diagnosis and
Control. Ann Arbor Press, Chelsea, Michigan.
16. Reicher, Z. 2002. Personal interview. Associate Professor, Turfgrass Extension
Specialist, Purdue University.
17. Robbeloth, K. 2002. Personal interview. Superintendent at Valley View
Golf Club, Floyds Knobs, Indiana.
18. Rogers, R.A., J.H. Dunn and C.J. Nelson. 1997. Photosynthesis and cold
hardening in zoysia and bermudagrass. Crop Science 17:727-732.
19. Tisserat, N. Feb. 19, 2002. Large Patch Disease of Zoysiagrass –
Rhizoctonia solani. (http://www.oznet.ksu.edu/dp_hfrr/extensn/largptch.htm).
20. Turgeon, A.J. 2002. Turfgrass Management. Prentice Hall. Upper Saddle
River, New Jersey.
21. Will, C. 2002. Personal interview. TenBarge Seed Company, Haubstadt, Indiana.
22. Williams, D.W. 2001. Defining Optimum Seeding Dates for Establishing Bermudagrass
and Zoysiagrass Fairways in the Transitional Climatic Zone. 1999-2000 Turfgrass
Reseach Summary, University of Kentucky.
23. Youngner, V.B. 1961. Accelerated wear tests on turfgrasses. Agronomy
Journal 53:217-218.
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