Selection and Establishment of Creeping Bentgrass On a Golf Course in the Twenty-First Century

Transcription

1 Selection and Establishment of Creeping Bentgrass On a Golf Course in the Twenty-First Century Richard Hurley Ph.D. Adjunct Professor Rutgers University Introduction to some new creeping bentgrass varieties, 2006 NTEP trials, and results. Recently released varieties of interest include: Over the past twenty-five years, turfgrass breeders have spent a significant amount of time developing improved creeping bentgrasses. In my own turf-breeding career, I started collecting bentgrasses from old putting green turf in the early 1980 s along with Dr. C.R. Funk of Rutgers University. Ten years latter, this project led to the development and commercial release of the creeping bentgrass varieties Southshore and L-93. The 93 in the name L-93 was selected to indicate the year the variety became fully commercially available for purchase. One new bentgrass variety is named 007 with the inspiration for the naming of this variety being the year 2007; this is the year 007 will be fully available to golf course superintendents. The creeping bentgrass variety 007 was bred with germplasm released from Rutgers University under the direction of Drs. Bill Meyer and Stacy Bonos. For golf courses 007 is recommended for seeding or sodding putting greens, tees, and fairways. This new creeping bentgrass variety will adapt well to low mowing on greens or for reduced fungicide use on fairways and tees. All individual parental clones of creeping bentgrass used in the development of 007 were selected for improved dollar spot resistance, medium bright green leaf color, not displaying cool weather purple coloration, and a vigorous, uniform, moderately dense growth habit. The creeping bentgrass variety 007 has a broad genetic base developed using twenty four (24) parent plants. Plants identified from the varieties L-93 and Southshore were used in the breeding of 007. Two other new creeping bentgrass varieties of note have performed well in turfgrass evaluation trials. Dr. Leah Brilman, Director of Research, Seed Research of Oregon developed both Mackenzie and Tyee. Some of the germplasm used in the development of Mackenzie and Tyee was screened and evaluated at Rutgers by Drs. Meyer and Bonos. The bentgrass germplasm was released to Seed Research for use by Dr. Brilman in the development of these two new bentgrass varieties. 1

2 Tyee has tested well and will provide a fine, dense, and upright growing turf when used for seeding putting greens. Tyee has recorded improved turf quality ratings compared to the A and G varieties. Dr. Brilman says, If a superintendent desires a low cut, high quality dense putting surface, I would recommend Tyee over the A and G varieties. Tyee will provide a better putting surface with less thatch management. Mackenzie has performed well in turf evaluation trials and is an all-purpose variety well adapted to establishing greens, tees, and fairways. Dr. Brilman reports, I am very excited about the performance of Mackenzie, as it is one of the highest rated new varieties coming to market. Mackenzie has shown aggressive lateral growth, ideal for fairway use and for excellent divot recovery. Are you taking a risk when selecting a new variety? I am frequently asked this question, I don t want to be a Guinea pig with a new bentgrass variety. My response is simple. If you select a new creeping, bentgrass variety from a reputable breeding program you can be sure that these varieties have been thoroughly field-tested and evaluated to produce a broad genetic base. Additionally, with the NTEP (National Turfgrass Evaluation Program) testing conducted at twenty-two independent University sites across the US and Canada, data confirms the enhanced qualities needed for producing a high quality bentgrass turf. Most importantly, parent plants for new varieties have survived the test of time growing on old putting greens. Over the past forty years turfgrass breeders at Rutgers and other institutions have visited hundreds of old well established golf courses in the United States. During a site visit small patches of putting green turf are collected. The only plants identified for collecting are ones that appear to be attractive, fine textured, dense, upright growing and free of disease. Some of the old putting greens observed are over seventy five years old and we feel that some plants collected have been growing and surviving, under the wear and tear, on actual greens, for generations. For example, the collected plants are brought back to Rutgers turf research farm in New Jersey for evaluation. Collected plants, commonly referred to as germplasm, are labeled with the collection location and added to the largest collection of creeping bentgrass germplasm found anywhere in the world. After a few years of evaluation only the best one or two percent of all plants collected will be considered for use in breeding a new bentgrass variety. Ninety eight to ninety nine percent of collected plants will be discarded. Only the best performing plants will be used for developing a new variety. Typically, it takes ten to twelve years to breed and commercially release a new improved bentgrass variety for use on golf course greens, tees, or fairways. For example, with the breeding and development of the new variety 007 plants identified from the varieties L-93 and Southshore were used in the breeding of 007. Additionally, some of the parents of 007 can be traced to plants collected from old putting greens from 2

3 Piping Rock GC (7), LI, NY; Spring Lake GC (2), Spring Lake NJ; Northshore CC (2), LI, NY; Rumson GC (1), Rumson, NJ; and Harkers Hollow GC (1), Harmony, NJ. So, when someone asks me about taking a chance with the use of a new bentgrass on their golf course I direct them to the NTEP.org website for bentgrass turf evaluation trials. If a golf course superintendent has interest in using one of the new bentgrasses now currently available I find no risk or concern as long as the superintendent does his homework and selects highly rated varieties for use National Turfgrass Evaluation Program (NTEP), 2004 turf quality ratings, bentgrass putting green trials, turf quality ratings. Turfgrass Quality Ratings 1-9; 9 = Idea Turf 007 (DSB) Declaration 6.3 Shark (23-R) 6.3 Tyee (SRX IGD) 6.2 CY T Penn A IS A Independence 6.1 Memorial (A03-EDI) 6.1 Mackenzie (SRX IGDP) 6.0 LS Bengal 5.9 Alpha M 5.9 Kingpin (9200) 5.8 Benchmark DSR 5.8 Pennlinks II 5.7 Penncross 5.2 LSD.05% 0.2 3

4 What you can expect today from a mature bentgrass turf such as 007, Mackenzie or Tyee creeping bentgrass. Turf density: When used on putting greens Tyee, will produce a turf with similar density compared to the Penn A varieties. When used on putting greens, Mackenzie will produce a turf slightly less dense compared to the variety Tyee. 007 will provide a putting surface with density similar to L-93. Leaf texture: Tyee and Mackenzie will produce a turf with similar leaf texture compared to the Penn A varieties. 007 will produce a leaf texture similar to L-93. Less Poa annua: Greater turf density for Tyee, Mackenzie, and 007 compared to most creeping bentgrass varieties allows for greater competition against Poa annua invasion. Disease resistance: A golf course superintendent can expect above average disease resistance for Tyee, Mackenzie, and 007. No major weaknesses have been reported for these varieties based on university turf evaluation trials. Cultivars Leaf Texture Summer Density Brown Patch Dollar Spot 1-9; 9 = Very Fine 1-9; 9 = Max Density 1-9; 9 = No Disease % Disease 1-9; 9 = No Disease NJ TX PA UT ME NJ* KY IN (DSB) Penn A Declaration Independence Benchmark DSR NA NA Pennlinks II NA NA Penncross LSD

5 Thoughts on older creeping bentgrass varieties: Penncross has not performed well in the turf quality rankings (NTEP.org) and may be the least desirable variety for seeding putting greens. The Penn A and G varieties are no longer the highest rated bentgrasses. Many new varieties have tested to be equal or better for overall turf quality compared to the Penn A and G varieties. We know genetic diversity (in a variety) provides greater stability and lessens the chance of a catastrophic disease epidemic. Did you know some of the least diverse bentgrasses are the A and G varieties? Blending seed of the A and G varieties does not accomplish adding genetic diversity to a creeping bentgrass turf. L-93 is not patent protected and the breeders of L-93 have not been involved with quality control for approximately ten years. Seeding options for golf course fine turf New creeping bentgrasses: Greens: 007 and Mackenzie for moderate to high density and Tyee for high density, lowest cut putting surface. Tees and Fairways: 007 and Mackenzie for improved disease resistance and most competitive against Poa annua. Chewings fescue as a companion grass for seeding with bentgrass. Why? Using Chewings fescue in conjunction with bentgrass (125 pounds for Chewings seeded with 20 pounds per acres for bentgrass) aids in quick establishment and lowers the seed cost per acre. Additionally, Chewings fescue is highly resistant to take-all patch disease compared to creeping bentgrass, which is very susceptible (when seeded in sandy soils with a high soil ph). Basics for successful seeding of creeping bentgrass on a golf course Best dates to seed: New establishment: August September is the most desirable time to seed a new bentgrass turf. Important factors include warm soils, less problems from summer annual weeds, and two seasons of growth (fall and spring) prior to the heat stress of summer. A late summer seeding should be ready for play the following spring. 5

6 April May is the second best time to seed a new bentgrass turf. A spring seeding has limited time to germinate and mature prior to the arrival of summer. An early spring seeding may be ready for play by September October of the same year. The above is a general recommendation for most cool season or transition climates. The exception would be for mountain high elevation sites with short cool summers. Under these conditions seeding should be scheduled as soon as possible in late spring / early summer. Interseeding an existing turf: Research conducted by Dr. Jim Murphy at Rutgers University has shown that June July interseeding into a mixed Poa annua bentgrass turf may be the best time to incorporate bentgrass seed (with use of a spiker seeder). Repeated introduction of creeping bentgrass seed, at two three week intervals during June - July, may be helpful. Creeping bentgrass seeding rates: Greens: Two pounds per 1,000 square feet Tees: Two pounds per 1,000 square feet Fairways: Eighty pounds per acre For interseeding existing turf, use twenty five percent of the above rates. Germination and seed storage: Expected germination: With a late summer seeding, under most conditions, creeping bentgrass will germinate in four to seven days after planting. For a spring, seeding germination will be slowed a few days by cool soil conditions. New crop vs. old crop seed: If seed is stored under cool dry conditions bentgrass seed can be stored for up to four years and retain an acceptable germination rates. If provided a choice year old seed may be preferred to new crop seed due to potential after ripening dormancy (lower germination rate) that may be observed (in new crop seed). 6

7 Steps for success for seeding a new bentgrass putting green: Seedbed preparation and floating a new green: Extreme care with surface leveling before seeding is very important. The process includes use of a sand pro after saturating the surface with water applied by a hose and showerhead. This procedure should be repeated numerous times prior to hand raking the finished grade for seeding. If a putting green surface is not level, it may take years of topdressing to improve the situation. The shade environment: Trees and putting greens are not a good combination. If a putting green or tee site does not receive a minimum of four to five hours of direct sunlight per day one can expect issues with managing a bentgrass green. Morning sun is preferred to afternoon. Keep in mind the angle of the sun changes with the seasons. Sufficient sunlight reaching a green or tee during June does not mean this same green or tee will receive sufficient direct sunlight during September October. Soil testing: Physical testing (i.e., sand / silt / clay): Acceptable sand for use in building a new putting green should have approximately 50% (of the sand) as medium sized particles. Angular sand shape is preferred; sharp sand may cause excessive mechanical damage to plants. Round is the least desirable particle shape for putting green sands and will create an unstable surface. When reviewing the physical test, keep in mind that a maximum of 6% total silt and clay is acceptable. Infiltration rate: From laboratory testing for water infiltration rate desirable sand should be in the range of between twelve to fifteen inches per hour. From this you can expect a 50% reduction in water infiltration rate two to three years after turf establishment. Nutrients: Follow preplant and post establishment fertility recommendations based on soil testing from a qualified soil laboratory. Soil samples should be taken at four to six month intervals during the first two years of turf establishment. Calcareous sands and high ph: Be wary of calcareous sands available for turf use that meet physical testing standards but are difficult to manage due to high soil ph (over ph 7.5). Bentgrasses are very susceptible to take-all patch disease, which is normally a problem when maintained in high ph soils. The best recommendation for fertilization of a calcareous sand based growing medium is by foliar feed. 7

8 Water quality testing: Check irrigation water ph and take measures to adjust water to ph Use of high ph water for irrigation may assist in causing take-all patch on bentgrass turf. Additionally, use of high ph (over 7.5) water for use with pesticide and fertilizer sprays may cause inefficiencies for product use. Check labels and manufacture recommendations for use under high ph. Fertility for a new putting green turf: Pre plant: Follow soil test recommendations from a qualified soil laboratory. After germination: Apply one half pound of Nitrogen per 1,000 square feet every three / four days on newly seeded putting greens. Follow this procedure until total (100%) bentgrass coverage of the surface is achieved. Fertilizer applications should be made to a dry surface and water the fertilizer off the leaves immediately after application. After four months from seeding a new putting green: Apply one half pound of Nitrogen per 1,000 square feet every seven days. During the first growing season, it is not uncommon to apply ten to twelve pounds total nitrogen per 1,000 square feet (applied with approximately twenty to twenty four individual half pound applications). Total nitrogen applied will depend on length of the growing season and appearance of the turf surface. After one year from seeding a new putting green: Year two after establishment of a bentgrass putting green should receive approximately four to six pounds of nitrogen per 1,000 square feet during the growing season (with approximately eight to twelve applications). After putting green maturity: It takes approximately three years for a new putting green to reach maturity. Maturity of the bentgrass plants and of the soil. New sand based putting greens are initially devoid of activity of soil organisms. It takes time for bacteria and fungi to colonize and develop a balanced biological system. Until this develops it is common to see greater activity of some turfgrass pathogens. For best performance, a mature putting green seeded to 007, Mackenzie or Tyee bentgrass should receive four to six pounds of nitrogen per 1,000 square feet per year. Total nitrogen applied will depend on length of growing season and appearance of the turf surface. 8

9 Do s and don t when seeding a new bentgrass putting green: Your checklist includes: Variety selection is most important: Use of a variety known to have poor turf quality performance will limit turf performance potential. Check NTEP.org for creeping bentgrass quality ratings. Seeding rate targets: Two pounds per 1,000 square feet or 80 pounds per acre. A higher seeding rate may reduce time for establishment but may increase the probability of seedling diseases. A low seeding rate will delay establishment. Seeding during June / July is not recommended: Summer seedings of creeping bentgrass are not recommended except for sites with a short summer season (i.e., high elevation locations in the mountains). Irrigation to keep the surface damp: After seeding light frequent irrigation cycles is recommended (i.e., Ten AM, Noon, Two, Four, Six, PM). Fungicides: If temperatures are above eighty degrees F apply a Pythium control product to the germinating bentgrass seedlings. Re-apply according to manufacture recommendations as needed. Root Pythium and putting greens: Death of plants is due to a combination of mechanical injury from mowing stressed plants with dysfunctional root systems. After the plants are weakened, roots are infected by Pythium spp. Use of mulch on new seedlings: First preference would not be to use mulch in conjunction with seeding a new bentgrass green. Do not want to use sawdust or freshly harvested wood mulch. Do not want to create a layer that will remain beyond seed germination and bentgrass establishment. Rolling: To firm the surface prior to mowing (for the first time) roll a green two or three times with a hand greens mower (with the blades off). First mowing: Commonly three / four weeks after seeding a green the first mowing would be scheduled. The first mowing should be set at one half (.500) to three quarter (.750) inch height of cut. The second mowing set at one half inch and by the fourth or fifth mowing lower to one-quarter (.250) inch. From this point, lower the mowing height slightly each week until the desired height of cut is achieved. 9

10 Scalping bentgrass: Do not allow a new bentgrass seeding to grow more than one inch in height before mowing. Once mowing has been initiated, practice mowing greens a minimum of four times per week on putting greens and three times per week on fairways and tees. Bentgrass bloat phenomenon: Some varieties are more prone to Bentgrass Bloat which may occur in June after high humidity / rainfall causes the thatch / crowns to elevate with subsequent mower scalping. Although possible with any creeping bentgrass, this phenomenon has been observed to do significant scalping damage to the creeping bentgrass variety Declaration. Topdressing: When: Start light topdressing every seven days after total bentgrass cover has been achieved on a green. Do not initiate topdressing prior to one hundred percent turf cover establishment. What not to do: Use the same sand (or closest match) as used for building the green. Do not use a topdressing material dissimilar to the existing growing medium. Be careful of abrasive sands and excessive mechanical damage that my occur on young bentgrass greens. Do s and don ts for successful bentgrass establishment, and maturity of a bentgrass turf? Your checklist includes: Black layer on new sand based putting greens: Black layer is a physical condition normally associated with high-sand based greens. Anaerobic conditions in soil are the cause of black layer. Black layer develops during periods of excessive rain or because of excessive irrigation, especially on greens with poor internal soil drainage or where soil water perches. The condition is frequently encountered where sand topdressing is layered over a thatch layer. Black layers also develop on sodded greens where the soil from the sod forms a layer effect. These situations cause water to become trapped in the upper layer, resulting in soil becoming anaerobic. Fertility levels for creeping bentgrass: Many times slow establishment of a new creeping bentgrass green is due to insufficient fertility during the grow in period. High water ph may predispose a turf to take-all patch: Check ph of the water source and take measures to modify if above

11 Poor quality control / selection of sand based growing medium: Check each truckload of soil mix to make sure they meet specifications. Poor surface preparation (i.e., not floating out the surface) may create an uneven putting surface: If a green surface is rushed to seeding without proper attention to attain a level surface it will take years of topdressing to correct the problem. Abrasive topdressing may damage turfgrass plants: Care should be taken on young tender plants not to cause mechanical damage to plants resulting from a gritty sand topdressing. Bentgrass collar decline: Death or decline of collars or greens approach is primarily due to mechanical injury. Injury is most severe where mowers turn, walk-on and walk-off areas, and areas adjacent to bunkers. Mowing young bentgrass on collars during rainy periods or whenever the turf is excessively wet or spongy cause severe damage in the summer. Soil layering may cause serious turf issues: Topdress frequently, at regular intervals, through out the season and select a topdressing material that is the same or closely resembles the sand used for constructing the putting green. Mechanical damage: Caused by the bruising of grass plants as a result of mowers or other equipment turning sharply, on curved areas, driving over the same spot or continued use of a similar mower pattern. The turning and twisting grinds leaves and stems. Bentgrass Bloat: May occur in June after high humidity / rainfall causes the thatch / crowns to elevate with subsequent mower scalping. Shade and putting green turf: Trees must be thinned or removed to provide a minimum of four to five hours of sunlight per day (from April through October). Play too early after seeding will delay turf maturity: Under most situations it is not recommended to open a new putting green before seven or eight months after seeding. 11

12 Frequently asked questions? Thatch management: One quarter to one half-inch thatch is good, provides a cushion, and should be maintained. One inch or more thatch is excessive and should be reduced by verticutting and aerification. When will a new putting green be ready for play: August / September seeding should be ready for play by April / May of the following year. April / May seeding should be ready for play by September / October of the same year. What will happen if a new green is open for play prematurely: May set back performance and putting surface quality for years. When does a new sand based green become mature: Three / four years after seeding. What does a mature sand / soil-growing medium have to do with bentgrass performance: Less disease problems with a mature soil-growing medium? When to aerify for the first time: Aerify for a purpose, compaction, or thatch management. Typically, new putting greens do not require aerification during the first year after seeding. Poa annua, the plant: Poa annua contamination on a golf course results in a large supply of Poa seed to spread around the property. Individual plants are capable of producing 1,000 2,000 seeds per season. The seeds are viable in soil for over five years. Poa annua control, can you win: Select dense aggressive bentgrasses that can effectively compete with Poa annua (e.g., 007, Tyee, or Mackenzie). After turf is established irrigate to a minimum; keep the turf as dry as possible. Collecting clippings removes Poa seed and reduces the spread of seed (one plant of Poa annua is capable of producing over two thousand seeds per year). Solve drainage problems as needed. Hand pick, cut out small Poa plants on greens each day / week of the growing season. Schedule to plug out larger patches of Poa annua on greens as required. 12

13 Resod collars, tees, and fairway bentgrass areas infested with more than % Poa annua. Never let Poa annua become established in large patches or areas of greens, tees, or fairways. Apply most of the Nitrogen fertilizer to bentgrass during the heat of summer. Bentgrass grows best when summer heat arrives. Poa annua grows best during the cool spring and fall months. Applying Nitrogen during cool weather provides the advantage to Poa annua. For bentgrass greens, applying one third to one half pound of Nitrogen, at ten-day intervals, during June, July, and August. Institute a chemical control program and commit to timely applications (PGR s such as the product Trimmit chemically know as Paclobutrazol). Richard Hurley s life experience includes working as a golf course superintendent, participating in turfgrass management education and research at Rutgers University, preparing golf courses for tournaments, playing golf around the world, being a student of golf history, associating with various golf course architects, and becoming involved with dozens of golf course construction projects. 13