With news, information, online message boards, and links to a variety of suppliers, this is a site that may be of interest to turfgrass managers in Asia. Check it out here.
This soil profile, showing how the soil has been modified after about 70 years of management as a golf course putting green, is absolutely fascinating. This photo is from a course at Sydney, Australia. Because this hole is now closed for a complete renovation, the superintendent decided to make some archaeological researches by digging down to the original dune sand that the green was built on. Click on the photo above or click here to get a full size image for closer inspection.
Starting from the bottom of the profile, we can see the clean sand that is the original dune, meters deep, that the green was planted on. Moving up, we see darker material at the base, this probably being some organic material that was mixed in the soil at the time of planting the green. Then we start to see distinct layering, dark and then white bands moving horizontally across the profile; these would be the bands of sand topdressing laid down at annual renovations, as the scarifying-aerifying-topdressing activity is often referred to in Australia. And we start to see aerification holes, filled with sand from decades ago, still providing that vertical channel through the soil profile that is so critical to rapid air and water movement.
Moving up through the central part of the profile we can see perhaps a change of topdressing sands, perhaps some periods when more coring was carried out, and less topdressing sand was laid down, and then nearer the surface we see even more coring holes filled with sand, and what appears to be a higher organic matter content, still diluted with sand, but perhaps less so than lower in the historical profile.
This profile is one of the most interesting things I've seen on a golf course, and it helps to remind me that the maintenance work we do on a daily basis will have an impact on how water, nutrients, and air (and consequently roots) move through the soil profile for years to come.
In the past two weeks I've been to Brisbane, Adelaide, Melbourne, and Sydney. I visited the Redlands Research Station in Queensland where there are numerous experiments about turfgrass and where one can find an extensive collection of turfgrass demonstration plots.
Then I went to Adelaide for the Australian Turfgrass Conference. The AGCSA invited me to speak about plant nutrition, warm-season grass selection, and the management of turfgrass in difficult growing environments. In the plant nutrition presentations, I discussed the role of nitrogen in controlling the energy production of turfgrasses. The net CO2 uptake is controlled by light, temperature, water status of the plants, and the nitrogen levels in the leaves. Light and temperature are largely out of the control of turfgrass managers. Water and nitrogen, however, can be controlled precisely to modify the photosynthetic rate of the grass, and consequently the growth rate and performance of the turgfrass.
I also spoke about the types of grasses that perform well in Southeast Asia and suggested why certain grasses perform well and others do not. One thing I have noticed in my travels across Australia is the variety in turfgrass species that are used to produce fine sporting surfaces. I've seen golf courses or sports fields of kikuyugrass, bermudagrass (green couch), creeping bentgrass, colonial bentgrass, fine fescue, perennial ryegrass, mixed in with Axonopus compressus, Poa annua, and Digitaria didactyla (blue couch). Although the climate in Southeast Asia is a bit extreme with high temperatures year-round and relatively low sunshine, there is an advantage to that when it comes to grass selection for sports turf, as there are really only a few species than can be used to produce the desired playing conditions. In Australia, the climate throughout the year is much more variable, and consequently more grass species can be used.
I met old friends and made new ones at this conference. Brian Whitlark from the USGA Green Section was also here to speak at the conference. I'm happy to report that our team in the AGCSA/Toro Scramble made eight birdies and no bogeys on a windy and cold morning at Adelaide Shores during this fun networking event.
I had a great time speaking with conference delegates and have learned a lot as I have traveled around Australia to see how turfgrass surfaces are prepared for a variety of sports here. From the sports fields at the University of Queensland to the wickets at the Adelaide Oval to catching an AFL game at the Melbourne Cricket Ground, from the Mornington Peninsula to Melbourne's sandbelt courses to the three courses I visited at Adelaide, I have had a chance to talk with turfgrass managers who are passionate about the same thing — producing the best possible surfaces.
If you attended the Sustainable Turfgrass Management in Asia 2010 conference, you met Matt Roche and saw his presentations about the trials being conducted at Australia to evaluate new warm-season grasses (bermudagrass and seashore paspalum varieties) and to determine the best management guidelines for these grasses. The final report on this project is now available for download from AGCSA Tech:Management Guidelines for New Warm-Season Grasses in Australia, Matt Roche et al., 167 pages, 4.6MB
In addition to the full report, which includes information about many grasses used in Asia such as TifDwarf, MiniVerde, TifEagle, Novotek, Sea Isle 2000, Sea Isle Supreme, and SeaDwarf, a video presentation with a summary of the project and key results is also available for viewing:Video Webcast of Matt Roche on Final Results of Australian Warm Season Grass Trials
Nematode damage can cause severe problems on highly-maintained turfgrass. I have recently received a number of inquiries about nematode control, and I wanted to share some information on this topic for those who may be interested.
Nematodes are very small worms; there are many different species of nematodes, some of which are harmless or even beneficial, and others that damage turfgrass plants which are termed plant pathogenic or plant parasitic nematodes. In short, the problem associated with high populations of plant pathogenic nematodes is a stunted root system. When the root system is restricted, the turfgrass will be particularly susceptible to drought, nutrient deficiencies, and other stresses.
For a summary of the problems nematodes may cause, what control measures are available, and how to minimize nematode damage, I recommend this article from Australian Turfgrass Management, Managing Nematode Pests on Turfgrass by Dr. Graham Stirling.
I would summarize the turfgrass nematode problem by noting three crucial points:
- There are very few chemicals that can be used to control nematodes, these products tend to be extremely toxic, and their use should be minimized
- By the time you can see turfgrass damage from nematodes, it is too late; the damage is done, it will take careful management to allow the grass to recover, and pesticide applications at this point may allow the turf to recover faster, but there is already significant damge.
- This is the crucial point - MINIMIZE turfgrass stresses so that nematode damage does not cause unplayable turfgrass conditions. Create a rootzone environment that is amenable to turfgrass root growth, avoid drought stress, eliminate any nutrient deficiencies, don't cause undue stress on the turf by cutting with dull blades or smothering the leaves in topdressing sand. If we can reduce the stress that the turf is under, nematode damage will be minimized. As Dr. Stirling wrote in his article:
Nematodes can cause severe damage to turfgrass stands, but the damage is not a given; by implementing a turfgrass management program that minimizes stress on the turfgrass, turfgrass problems associated with nematodes can be avoided.