Viridescent - the Asian Turfgrass Center blog

Cynodon, Paspalum, and Zoysia at Putting Green Height

Golf course putting greens in Southeast Asia are usually planted to either hybrid bermudagrass (Cynodon dactylon x C. transvaalensis), seashore paspalum (Paspalum vaginatum), or zoysia (Z. matrella or Z. pacifica). I saw this test recently at a golf course in Southeast Asia. This is a putting green in an area with extensive cloud cover for much of the year. Can you identify the species being grown here? Which are bermuda, which are paspalum, and which are zoysia?

This green is being maintained at about 4 mm, the test plots have been established for more than three months, and there are obviously some differences in how the grasses perform at this mowing height. This test corresponds exactly with what I have observed on the performance of these grass species at low mowing heights across a broad swath of Asia.

Turfgrass Teaching in India

I spent the last month at Kolkata, New Delhi, Mumbai, Coimbatore, Kodaikanal, and Bangalore, conducting a Greenkeeper Education Programme for the Indian Golf Union. Working with technical experts from the Asian Golf Industry Federation, we taught a series of weeklong courses in each of the country's four zones, providing practical information covering many aspects of golf course maintenance, with a focus on these topics:

• grass selection for golf courses in India
• how to produce the desired playing conditions
• operation and maintenance of reel and rotary mowers
• preventative maintenance of golf course machinery
• safe operation of turfgrass equipment
• introduction to irrigation, plant nutrition, and management of soil organic matter
• on-course sessions to investigate and apply what was learned in the classroom

The primary grass used on golf courses in India is Cynodon (bermudagrass). Some courses have been planted with Paspalum vaginatum (seashore paspalum). Zoysia matrella is used in landscape areas and on a few courses the zoysia has invaded the Cynodon but has not yet been planted on a golf course. Axonopus compressus grows well and provides the playing surface on many courses in the country. Those are the main grasses we discussed, although there is isolated use of Stenotaphrum secundatum, Pennisetum clandestinum, and Digitaria didactyla in the South, and there are some courses at high elevation at which cool-season grasses can grow.

This programme is supported by The R&A and aims to provide information and education that greenkeepers in India can use to develop improved playing conditions on the many golf courses across the country. See photos from the IGU Greenkeeper Education Programme here, or read more about the programme at its dedicated website.

Golf Course Flooding at Thailand

Yesterday on a flight departing Bangkok I flew over much of the flooded area in central Thailand. Riverdale Golf Club was still dry (above), but the adjacent 27 holes at Bangkok Golf Club are all flooded. See below for the normally sedate appearance of Bangkok GC (July 2009). 

Many of the courses around Bangkok are flooded or are at risk of inundation during these floods, as are many areas of the city. Here are dramatic images of the flooding in a photo gallery from The Atlantic. For the golf courses that are flooded, I expect the grass to survive. Fortunately, the warm-season grasses that are used at courses around Bangkok, zoysia, bermuda, and seashore paspalum, are able to tolerate weeks and even months of submersion. Dr. Jack Fry's paper Submersion Tolerance of Warm-season Turfgrasses explains that zoysia and bermuda can survive for two or three months under water. Research at Singapore found that seashore paspalum tolerated waterlogging and it is expected to recover as well once the flood waters recede.

In October 2006, when the Asian Turfgrass Center was being constructed at Bangsai GC in Ayuddhaya province north of Bangkok, floodwaters from the same river overflowed their banks and it was necessary to increase the height of the dike wall around the research area (right). That dike wall has been raised again, and it was raised yet again this year to protect the property from the floods.

Now five years later, the course is again at the risk of flooding but the higher flood barriers around it have so far protected the course from the rising waters. I flew over Ayuddhaya yesterday, and one can see the 27 holes at Bangsai, the only dry land for kilometers in the flooded Chao Praya basin.

What Grasses Are Growing on Golf Courses in Thailand?

In 2006, ATC conducted a survey of the grass types on golf courses in Thailand. Surveys were sent to the more than 200 courses in Thailand, and 41 of the surveys were completed and returned. Data from that survey are shown in this table:

I've visited or played golf at 24 different golf courses in Thailand since January 1, and I thought it would be interesting to summarize the different grass types that are being grown on these courses. Of the 24 courses I've been to this year, 79% have hybrid bermudagrass on the greens, 4% seashore paspalum, and 17% use Zoysia matrella. On fairways this year, 38% of the courses I've visited have seashore paspalum, bermudagrass and Zoysia matrella are each on 29% of the courses, and a native grass mixture is on 4%. 

I like the native grasses on the fairways because of reduced fertilizer and water requirements and the paucity of any pests on Zoysia or Axonopus in Thailand. Not only do these fairways have great color (see at right), they also have great playability.

At Thailand there has been rapid adoption of new bermudagrass cultivars. Nineteen of the courses I visited this year have bermudagrass on the greens, and of those there are two with Miniverde, four with Novotek, five with Tifdwarf, and eight with TifEagle.

Many of the older courses in Thailand such as Royal Hua Hin (pictured below) and Royal Bangkok Sports Club use a fine-bladed Zoysia on the greens. This grass requires little maintenance and produces a fine playing surface for year-round play. One thing I don't see much of on zoysia greens is algae — the grass leaves provide such a dense cover of the ground and the irrigation requirements are such that algae never has a chance to gain a foothold.

I wrote more about warm-season grass selection and maintenance in this article for Golf Business Asia in 2008. But no matter what grasses are used at the courses in Thailand, I think you will find that the playing conditions across the country are consistently among the best in Southeast Asia. With an active golf course superintendents association (the Thai GCSA), regular educational events such as the Sustainable Turfgrass Management in Asia conference, and a steady stream of new golf courses being built and older courses being renovated, Thailand is an exciting place to study grass.

World Cities Plotted by Climatological Normals, June

This bubble chart shows 45 world cities plotted by average June temperature, June sunshine, and June precipitation. The plot for May had 46 cities; because Kota Kinabalu and Brunei have similar weather conditions and often overlap on these plots, I have elected to omit Brunei for clarity.

Compared with May, the cities in India have more rain and less sunlight as some monsoons begin, and New Delhi is really hot, hotter than Dubai, Phoenix, and Las Vegas! Hong Kong still doesn't have much sunlight but there is more than in May. And there is a big difference in transition zone cities such as Shanghai, Tokyo, Osaka, and Atlanta; by temperature and rainfall these cities are similar but during the month of June there is a lot more sunlight in Atlanta. We can also see why it is difficult to grow bentgrass in Atlanta. The temperature in June is similar to Hawaii or Florida but the summer is just getting started.

World Cities Plotted by Climatological Normals, May

Last week I created a bubble chart showing seventeen world cities where warm-season (C₄) grasses are usually grown. The cities were plotted by average annual temperature on the x-axis, annual sunshine hours on the y-axis, and the size of each city's "bubble" on the chart was proportional to the city's average annual rainfall.

I have now made additional charts, with the number of cities in the dataset expanded to 46 to give a broader picture of the variability in climatological normals. And I have plotted the data on a month-by-month basis for a more detailed look at how the temperature, sunshine, and rainfall vary throughout the year.

Click the image above to view the bubble chart at a larger size. All data used to generate these plots are from the climatological normal tables for world cities as posted on the Hong Kong Observatory website. The bubble charts were created using the ggplot2 package in R.

I find it interesting to see how the average weather data for different cities change throughout the year. Of the 46 cities plotted here, Hong Kong stands out as having relatively little sunshine (on average) in the month of May. And in cities such as Tokyo and Osaka and Shanghai, where warm-season grasses are almost always used on fairways, the golfing season is well-underway but the temperatures are still too low for the optimum growth of warm-season grasses.

I think there is a lot of information in these plots that turfgrass managers may find interesting. As an example, Miami and Hong Kong have nearly the same average temperature in May, but Miami has more than twice the sunshine hours. This is the season when intensive cultural practices are done to control organic matter in bermudagrass greens in Florida; from looking at the bubble chart above it is obvious that the recuperative ability of bermudagrass at Hong Kong is probably much less in an average May than it would be at Florida. 

At which month is the temperature and sunshine at Tokyo the same as Singapore? How does this bubble chart change during the monsoon season in India? And does the sunshine at Hong Kong ever rise to the level of Miami? I'll post a new chart each month to show how the average weather changes in these cities over the course of a year.

A Plot of Cities Where Warm-season Grasses Grow, and more

I made the bubble plot above to see how the differences in temperature and sunlight and rainfall between cities would appear if plotted this way. The data are from climatological normals provided by national meteorological services and the World Meteorological Organization, collected in some cases from the climate section of a city's page on Wikipedia.

I made this plot for a few reasons. I saw a job posting for a superintendent position in Asia saying that experience working in a Florida-type climate would be desired, and I wanted to plot a few cities this way to see how cities in Asia compared with Florida. Someone also asked me if I thought it was more difficult to manage warm-season grasses in Singapore or in Florida, and I thought that a plot such as this might make my answer more clear. And I also notice as I travel that a grass that grows so well in Honolulu, for example, may not grow well at all in Bangkok. There are clear differences in suitability of grasses for different growing environments. And as I work with some new software, I saw a tutorial to make this type of bubble plot on the FlowingData website and I wanted to try it for myself.

When plotted this way with mean annual temperature on one axis and hours of sunshine on another axis (the area of the circle for each city is proportional to annual rainfall), one can see that the cities in Asia tend to have a higher annual temperature, have less annual sunshine than the cities plotted from the USA, and have substantially more precipitation. A quick look at the bubble plot shows that Singapore, for example, has about 60% the sunshine of Miami while receiving almost twice the rainfall. 

This doesn't tell the whole story about which grasses perform best in a certain area. We can also consider the winter temperatures, the summer temperatures, the timing of rainfall and dry seasons, etc., but simply plotting by temperature and sunshine tells us a lot. 

Turfgrass managers in Southeast Asia know that zoysiagrass (Zoysia matrella) and broadleaf carpetgrass (Axonopus compressus) thrive in this climate while bermudagrass maintained as a turfgrass struggles. This type of plot helps us to understand why. At the Marukatayawan Palace in Thailand, we see that zoysia grows in the sun and broadleaf carpetgrass covers the shaded areas under the trees.

These native grasses thrive when maintained as turfgrass in this region, while grasses such as bermudagrass which have a higher light requirement cannot compete with zoysia even in full sun. Why is that? Because even in full sun, there is still relatively little sunshine in Southeast Asia compared with Florida.

Herbicide Safety on Newly Sprigged Bermuda and Paspalum

This article by Patton et al. about the safety of various herbicides on seashore paspalum and hybrid bermudagrass during establishment/grow-in will be of interest to many turfgrass managers in Asia. Entitled Sulfonylurea Herbicide Safety on Newly Sprigged Bermudagrass and Seashore Paspalum, the research project was conducted in Arkansas and Louisiana and found that foramsulfuron, halosulfuron, metsulfuron, sulfsulfuron, and trifloxysulfuron can be used to control weeds in establishing Tifway bermudagrass.

For seashore paspalum, metsulfuron and halosulfuron applied two or four weeks after sprigging and sulfosulfuron applied four weeks after sprigging provided weed control without causing too much injury to the seashore paspalum turf. The Aloha variety of seashore paspalum was used in this experiment. If you are interested in using sulfonylurea herbicides on seashore paspalum, you will want to read the article for yourself.

Speaking at Philippine Turfgrass Association Meeting March 3

I'm really looking forward to the upcoming first quarterly meeting of the Philippine Turfgrass Association to be held at Sta. Elena Golf Club in Laguna on March 3. I'll be speaking on the topic of Application of Turfgrass Science Principles to Improve Grass Conditions. The morning seminar program will be about the modifications that golf course superintendents can make to the growing environment for bermudagrass, seashore paspalum, zoysiagrass, or carabao grass in order to produce the desired playing surface. Click here to register for the meeting.

An Interesting Technique to Modify Fairway Conditions in Thailand

Many of you will be familiar with the Laem Chabang International Country Club and its typical (for courses built in the 1990's) Tifdwarf bermudagrass greens and Tifway 419 bermudagrass fairways. Laem Chabang has been one of the sites for the Asian Turfgrass Field Day in recent years. Bermudagrass in this part of Thailand is notorious for having a high susceptibility to weed invasion, especially during the rainy season, and to require large amounts of nitrogen fertilizer to produce the desired surface. Seashore paspalum, as you know, performs better than bermudagrass in wet soils, and has a lower nitrogen requirement once established than does hybrid bermudagrass.

At the Sustainable Turfgrass Management in Asia 2009 seminars, I advocated the tolerance of, and sometimes even the deliberate planting of, turfgrass polystands in fairways and roughs. Why? Because the various attributes of the turfgrasses used in Southeast Asia can be complementary when the species are grown together, and the grasses are very difficult to eradicate when they begin to invade a monostand of a different species.

How many courses in Southeast Asia that try to have a seashore paspalum monostand fight bermuda as a weed? I would venture to say that all do, and especially in areas with poor irrigation coverage or where the turf is maintained at moderate to high mowing heights, I suggest that in the long term it is a losing battle. Bermuda will outperform paspalum in those areas. How many courses trying to maintain a bermuda monostand fight zoysia encroachment? Many do, and it is usually the zoysia areas that get larger and larger. And seashore paspalum can invade zoysia and bermuda as well — all this is natural. Why not take advantage of these grasses that seem to want to grow, and manage them to create a visually attractive playing surface?

At Laem Chabang, the Tifway 419 fairways were sliced on 10 cm centers and then caddies from the club planted individual plants of seashore paspalum into the fairways. How long does that take, you might wonder? About eight hours of work for 200 caddies to do one par 5 fairway.

After this slicing and planting of paspalum the fairways were topdressed with sand, and then it was maintenance as usual. I visited Laem Chabang five months after seashore paspalum was introduced to this fairway, and I found the conditions and the appearance of the fairway to be very good. The striping and color of the fairway appeared as would a paspalum fairway, but there is still a large amount of bermuda in the fairway. I expect that in wet areas and during the rainy season the paspalum will grow well and provide a dense turf cover when bermuda would not, and that during the dry season the bermuda will thrive and provide a dense turf cover when the paspalum would require large amounts of supplemental irrigation to produce such a surface during that season.

Thanks to course superintendent Mr. Boonthong Ngamsapang for the photos of the seashore paspalum planting process.