Prior to finalizing on a strategy for the future of the greens at LKCC the club engaged two internationally renowned grass scientists who specialize in grass species and management for golf courses to advise on our position.
Dr Richard Hurley specializes in bentgrasses having received a doctorate degree in grass breeding from Rutgers University (located 35 miles from New York City in the US). During his career he has consulted and worked the tournament week at the Augusta National Golf Club in preparation for the annual Masters Tournament, having just attended his 39th Masters. Additionally he has worked at numerous US Opens on tournament preparation. Other consultations on golf course construction and renovations include those in a wide range of climates in the United States, Canada, Europe, Russia, Japan, and South Africa. He recently was involved in advising on the renovations at the Wentworth Golf Club.
Dr Micah Woods has degrees in horticulture with an emphasis on turfgrass management from Oregon State University (B.Sc.) and Cornell University (Ph.D.). He worked as course maintenance staff at 6 courses in the United States and was golf course superintendent at Shanghai Links (China) for 2 years and at Habu CC (Japan) for 1 year. He established the Asian Turfgrass Center in Thailand in 2006. He has worked at many golf tournaments including the Masters (13 times), the U.S. Open (2 times), the Open Championship (3 times), and the Ryder Cup.
To enable the specialists to properly advise on our situation we employed local company Sports Turf Technology (“STT”) to conduct detailed testing of our greens and irrigation water.
Detailed below are summaries of the 3 reports prepared by the abovementioned specialists. The full reports are also attached for your information.
- GREENS AND WATER INVESTIGATION REPORT-STT
This investigation comprised of the following elements:-
Greens investigation
- Determine the depth of turf/soil that needs be removed from each green to get back to a clean sand with no organic matter, black layer or iron precipitate.
- Evaluate the existing sand profile that would remain after the top has been removed, by testing for particle size distribution (PSD), plant parasitic nematodes, presence of weed seeds and soil pH, salinity and nutrients.
- Determine whether fumigation is required after the surface layer has been removed.
- Measure the depth of the profile to the gravel layer.
- Evaluate the current water holding capacity of the sand root zone at various depths down the profile and compare to the current effective root depth of the turf.
- Evaluate other sand options for the turf root zone.
- Conduct ASTRC tests on good, average and poor greens. This includes infiltration rate, air porosity, water porosity, total porosity, solids, bulk density, water holding, 2.5 cm-by-2.5 cm analysis of organic matter content, depth of root mat and feeder roots.
- Conduct a vertical cut of the blue metal aggregate to check if it is blocked up with fines.
Irrigation water investigation
- Review the irrigation water test results (by bore and dam over time), volume of abstraction and groundwater level.
- Benchmark the LKCC groundwater abstraction depths with the other bores in the surrounding area.
- Investigate the feasibility of providing a higher quality source of water.
- Conduct an irrigation audit on selected greens to determine if the existing irrigation system is achieving a high uniformity of application
The results from the investigation and recommendations can be viewed in the attached report. The data collected was critical in enabling the two grass scientists to complete their reports.
- DR RICHARD H HURLEY REPORT
The purpose of this golf course site visit was to review and provide recommendations for general maintenance of the greens and to offer advice on the pending front nine green resurfacing / seeding scheduled for June and July 2017.
Upon studying the parameters of the STT report, which was confirmed during my site visit, I provide the following general conclusions concerning the USGA greens construction to include the perched water table style construction that was installed in 2007.
- The sand selected for use in building the greens in 2007 meets the standards for USGA construction.
- The perched water table as constructed in 2007 is working as designed and has not be compromised.
- The soil pH within the greens profile is within an acceptable range (between 6.3 and 6.7) for maintaining a bentgrass putting green.
- The 300 mm (12 inch) recommended sand based growing medium for the greens is at a variable depth in all greens. Based on STT reporting and research conducted by Fraser Brown and myself during my site visit we found the actual depth of sand in each green varies from 310 mm to 400 mm.
- It is advised that having a variable depth of sand in a green is acceptable within the range from a minimum of 300 mm up to 375 mm within each green cavity.
- When sampling the upper 100 mm of a green, we found this portion of the greens profile to be excessively moist, spongy and have readily observable formations of black-layer present.
- The upper 100 mm of a green appears to have created its own perched water table that retains excessive moisture at the surface not allowing the soil profile for the green to drain efficiently as designed.
- The lower two-thirds fraction of a greens cup cutter profile does not have black- layer and appears to be normal, allowing water to move through the soil profile.
- The irrigation water and the irrigation holding pond as recorded in the STT report has a pH consistently between 7.5 and 8.0. These results justify installation of an acid injection system at the pump house. A high water pH greatly affects the availability of critical nutrients necessary for healthy growth of turf.
- Sodium, bicarbonates and salts as found in the irrigation water all are detrimental to the soil structure and the ability to maintain turfgrass putting greens.
- High numbers of stubby-root plant parasitic nematodes (that restrict the development of root system) were reported in the STT report.
What is “black-layer”?
What we call “black-layer” in greens is a physical condition. The primary predisposing condition is anaerobic – lack of oxygen, in the soil. Bands of blackened sand are found. This condition is associated with periods of excessive rain or irrigation on greens with poor internal soil drainage. Soils of low oxygen are normally associated with black-layer.
With anaerobic conditions, sulfur combined with organic matter is converted by sulfate-reducing bacterial to hydrogen sulfide gas, which is highly toxic to roots of the grass. The blackening results when this gas combines with iron to form a sulfide precipitate. Roots are killed or restricted by lack of oxygen or contact with hydrogen sulfide gas.
Black-layer is controlled by eliminating or avoiding the creation of a perched water table and other reasons for soil waterlogging to include excessive irrigation, soil compaction, and poor soil drainage. Note the perched water table referred to in this paragraph is the unwanted perched water table in the black layer in the top 100mm of soil, not the perched water table under the USGA design created at the interface with the soil and the blue metal at a depth in the range of 300mm-375mm.
For the future, it is important to use sand of the same particle sizes to construct greens and for topdressing.
Frequent ninja tine or quarantine aerification or spiking / surface slits will allow for gas exchange, and allow oxygen to enter the soil implementing help to dry out the surface and alleviate anaerobic conditions from developing in a green.
Venting greens is an important tool to allow oxygen to enter the soil and should be scheduled to start during the summer warm season.
Also, as part of the overall plan to improve growing environments around each green, is the removal of physical barriers that restrict airflow to include trees and brush surrounding greens that should be pruned or removed.
Do not use applications of fertilizers or soil amendments, and do not use water sources that are alkaline with a pH of 7.0 and above. Do not apply products that contain significant amounts of sulfur, iron, magnesium, manganese, or organic matter.
Nitrate forms of fertilizer may help to reduce black-layer.
- Excessive water in the soil profile is the fastest way to attain an oxygen deficient environment for the turf roots. It is critical to schedule irrigation each day, based on demand, by using soil moisture probes on a daily basis. Grass roots must have access to oxygen to remain healthy.
- Hand watering greens as much as possible is the most desirable method to irrigate the greens.
- The goal is to strive to attain a uniform and consistent water movement throughout the 300+ mm depth of a greens profile.
- The plan is to allow no layers to develop throughout the soil profile. A layer can be made as a result of any texture differences created either by changing the topdressing sand, an organic material applied, or created by excessive thatch. Water does not move beyond a layer without resistance.
- Light frequent sand topdressing should be applied every other week throughout the year. This will help to dilute thatch production.
- Install an acid injection system at the pump house to lower the irrigation water pH. The acid injection will not only lower the water pH but will improve the salts, sodium, and bicarbonates in the irrigation water.
- STT will be submitting a plan to study the possibility of locating better quality of water.
- Until a better source of irrigation water can be found it would be wise to flush the greens at a minimum of twice a month during the summer dry season. Flushing the greens will move the salts and sodium through the sand profile in the greens. Without flushing the salts and sodium will be retained at the surface. The white crust members notice on dry or dead patches in greens are salts and sodium visible at the surface.
- Applications of the new nematicide named Indemnify should be applied once in the spring and once in the fall months to all greens.
- Once the new greens have been grown in, modify the previous fertility applications to exclude sulfur in fertilizers and pay attention to sulfur in fungicides and other supplements.
- Some green sites would benefit from additional direct sunlight. Bentgrass requires a minimum of four to five hours of sunlight reaching the surface each day of the year.
- Trees located around a green lessen air circulation and air movement that would aid in drying out the surface of a green.
On any golf course the vast majority of the time you will find the best quality putting greens on a golf course out in the open, on high ground, with good air circulation and full sunlight. Greens that suffer are found mostly in areas with trees and landscapes that restrict air flow.
3. DR MICAH WOODS REPORT
I visited Lake Karrinyup Country Club on May 11 and 12. We looked at the putting green grass and soil conditions, reviewed test data for the greens and irrigation water, and discussed putting green maintenance practices. Based on these discussions, my recommendation for the grass variety on newgreen surfaces is 007. The main reasons for this are its excellent performance in stressful conditions, combined with its growth habit that produces a moderate amount of organic matter. No matter what grass is used, tree shade onto the putting surfaces must be reduced so that the putting surfaces can perform well. During the green resurfacing project, I suggest making some minor shaping changes to the greens to ensure water has a route to move across the surface and off the putting surfaces, with fewer collection areas for water on the surfaces. This will improve the performance of the greens, especially in winter and summer. Successful management of the greens will involve management of the organic matter produced by the grass as it grows, while limiting the invasion of Poa annua.
NOTE: It is estimated that 007 has been installed at over 1,500 golf courses around the world including courses that have hosted major championships and the Ryder Cup. The Greens at Wentworth Golf Club for the recent BMW European Championship were on 007 grass that based on our timeline will equate to our greens this December. 007 has been installed in a large variety of climates including very hot conditions (e.g. Morocco, Southern California) and locations with similar conditions to Perth.
- RENOVATION DETAILS AND TIMELINE
As a result of the reports provided we have adjusted our greens renovations to include the following:
- Selection of the new generation bentgrass 007 for the greens renovations.
- Acquire an acid injection system so that water from the irrigation system has a PH in the range 6.5-6.8.
- Adjust the use of bore water into our irrigation dam to provide the best quality water available. Note there is substantial variation in water quality between bores.
- Use the nontoxic nematicide Idemnify to control nematodes. This has the added advantage due to its non toxicity of gaining 3 weeks in the timetable as we can seed 3 weeks earlier.
- Monitor salt buildup in the soil and flush it through when required.
- Exclude Sulphur in fertilisers and be careful with other supplements that contain Sulphur.
- Daily use of water probes to determine water content in greens and where necessary hand water to keep greens in the drier range of suitable water levels.
- Take away from the surface of the greens a minimum of 100mm of grass and organic material. Where the depth of soil to blue metal is well in excess of the recommended 300mm, adjust the amount taken to get the green to have a soil depth in the recommended range of 300mm-375mm.
- Apply light frequent sand topdressing to dilute thatch production.
- Adjust greens aerification program in line with recommendations.
- Apply gypsum regularly to replace the sodium and salts in the soil.
Timetable:
26 June: Strip greens on front nine and repair patches on back nine and North Course.
28 June: Spray Nematicide.
3 July: Shape greens and bunkers.
17 July: Seed greens.
2 August: Commence mowing.
27 November: Opening day.
To view a copy of the reports, please click on the links below or visit the Club News section of the website.