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March 2012

Turfgrass Mystery: what happened here?

What has happened here? Is it a disease, a fertilizer spill, different soil type, or perhaps a different type of grass?

This is on a golf course at an elevation of about 1,200 meters above sea level in Hawaii. We can also find this grass thriving at Dalat in Vietnam at 1,500 meters and at Kodaikanal in India at 2,000 meters.

Can you identify the type of grass? This species of grass is classified as a warm-season (C4) grass although it has intermediate characteristics between cool- and warm-season grasses, performing best at moderate temperatures. Click the image below to view at a large size.

I'll post the answer in a few days . . . and here it is:

This is white clover (Trifolium repens) growing in a stand of kikuyugrass (Pennisetum clandestinum) on the island of Hawaii. Clover is a legume that can fix nitrogen in the soil, and legumes mixed with grass can provide about 36% of the grass's nitrogen*. So we see the kikuyugrass has turned green where it is mixed with clover, and it has grown thicker, and taller, and faster, in fact so much so that it has been scalped, as we see in the background. This is an indication that the grass would respond with more growth if more fertilizer nitrogen were applied. Thanks to Nadeem Zreikat in Australia and Andrew McDaniel in Japan for solving this mystery.

*Heichel, G.H. and K.I. Henjum. 1991. Dinitrogen fixation, nitrogen transfer, and productivity of forage legume-grass communities. Crop Science:31(202-208)

turfgrass mystery

Korea, Winter Golf, and 45 New Courses in 2012

I visited Korea for a few days last week and am excited to write about it. Why? It was my first visit to Korea, and it is not often that I have a chance to write about my first impressions of a place. I visited five golf clubs around Seoul, comprising 126 holes (seven 18-hole equivalents), gave a seminar about bentgrass management during summer, and met with turfgrass researchers, golf course architects, and golf course superintendents. 

Blue-volvikIt was colder than I had expected, but not cold enough that golf courses close for a substantial part of the winter. It was cold enough that creeping bentgrass greens, even ones that are covered each night, were still effectively dormant during the 3rd week of March. I did not realize how cold it gets in Seoul. The average temperature during December, January, and February is below 0°C, and in March the average temperature is only 4.5°C. 

What grasses are used? Greens are creeping bentgrass. Fairways and roughs are predominantly planted to Zoysia japonica, although a smaller percentage of courses have kentucky bluegrass fairways, and perhaps some tall fescue in the rough. Tees are kentucky bluegrass or Zoysia japonica.

Traffic on the dormant grasses or slowly-growing grasses is a major issue, and the courses I visited were taking special precautions to protect the high-traffic areas as much as possible.


And the courses were busy! At the 27-hole facility where I gave the seminar, there were 400 rounds the day I visited. Golf courses in Korea have been busy, with average rounds a decade ago of about 90,000 per 18 holes per year. With so many courses being built, those round numbers are going down, and are now expected to be about 65,000 per 18 holes per year. I saw a newspaper clipping listing the 36 clubs that are scheduled to open this year, with a total of 810 holes, or 45 18-hole equivalents. 

I visited the Samsung Everland Turfgrass & Environment Research Institute, listened to a presentation from the scientists there about the work that they do, spoke a bit about some of the work I have been doing recently, and visited a golf course with their team to assess the turf and soil conditions.


Korea is a difficult place to produce good turf conditions because of the cold winters with heavy traffic on dormant grasses, then hot summers with low light and high humidity. I was impressed with the grass conditions I saw, considering these significant challenges, and I look forward to my next visit when I can learn more about the techniques greenkeepers in Korea are using to produce such fine playing surfaces.

A Report from Sustainable Turfgrass Management in Asia 2012

Turfgrass Discussion

Last week, 197 delegates representing 20 countries gathered at Pattaya, Thailand, for the 4th Sustainable Turfgrass Management in Asia conference. The topics included a review of research in Asia over the past six years, management and prevention of fungal diseases that infect turfgrass in Asia, wetting agents, management of soil moisture, evaluating light conditions, playability of golf course turf, fairway conversion to seashore paspalum using a simple and non-disruptive technique, and how the courses are maintained at multiple award-winning Siam Country Club. 

bunkers and rough

At the field day, we visited Phoenix Country Club, Siam Country Club, and Laem Chabang International Golf and Country Club, were joined by golf professional Virada Nirapathpongporn who discussed golf course maintenance and playability, had equipment demonstrations from the Asian Golf Industry Federation, saw some really cool soil moisture meters and light meters from Spectrum Technologies, and had a lively party hosted by the Thai GCSA in the evening.

The reviews for this year's conference have been of one voice: "such an eye-opening and impressive program," "a great experience," "very informative for issues facing turf managers on a daily and weekly basis," "of great value to us," "an excellent and very enjoyable conference."

mini ring

Sustainable Turfgrass Management in Asia is organized by the Thai GCSA and ATC on behalf of the Thailand Golf Association. It is supported by The R&A and in 2011 and 2012 has also received support from AGIF. Thanks to all who participated in this conference in 2012, and we look forward to seeing you next year at Sustainable Turfgrass Management in Asia 2013. 

Turfgrass Climate Charts, a new website

I've been making various climate charts since last May which show the climatological normal data for a number of world cities. These charts are of particular interest to me because the combination of normal temperature and normal sunshine duration for a location give a very good indication of what grasses will be best-suited for planting as turfgrass there, and of what maintenance practices may be required, and when, on the grasses that have been planted there.

Now I've made a website that hosts all of these charts:


What you will find on this site are links to all the static charts I've made, the interactive motion charts (or moving bubble plots) and a guide to how they can be modified, videos I've made about this topic, links to the data sources, and to the software used to create the charts — in short, just about everything created so far in this project.

Still to come are more charts, for more areas of the world, links to the videos on this topic made by the Global Relva and Global China sites of the GTN Network (Thank you!), and a lot more explanation about how these charts can be used, and why these data are meaningful and practically useful for turfgrass managers. For those of you who have requested charts for certain areas, I have been noting those requests and have a list of charts to make; if you are interested in these types of charts and would like to see one with data for an area that I have not so far included, please let me know and I will do my best to create such a chart.

A Chart of Golf Courses in East, South, and Southeast Asia, by Country

Data: • Chart ID: GeoChartID185f4115a9f
R version 2.14.2 (2012-02-29) • googleVis-0.2.14Google Terms of UseData Policy

This chart shows the number of golf courses, by country, for East, South, and Southeast Asia. I've estimated the number of courses by country and in some cases may have made substantial errors in the estimates, so if you have the correct information, please send it to me and I will update this chart.

The total number of courses in these regions of Asia, by my estimate, is 4,500. Slightly more than 50% of those golf courses are in Japan.

Can You Identify the Grass and the Disease?

a fungal disease

Can you identify the grass and the disease? This is a warm-season grass, in Southeast Asia, maintained at a mowing height of about 25 mm (1 inch). The average temperature during this season is about 17°C. Answer to be posted in a few days. 

Answer: This is seashore paspalum (Paspalum vaginatum) showing typical symptoms of dollar spot. Seashore paspalum grows most rapidly when average temperatures are more than 25°C. With the temperature at less than the optimum for seashore paspalum growth, but within the optimum range for dollar spot to grow, we can see this type of severe damage.

For some advice about dollar spot control on seashore paspalum in Asia, see this post from the Turf Diseases website:

Suggestions on the Right Maintenance for the Wrong Grass

World Cities Plotted by Climatological Normals, March


This is the best time of year for warm-season grass growth at places such as Bangkok, Kolkata, and Colombo. Temperatures are near the optimum for growth and there is plenty of sunshine for photosynthesis.

At Hong Kong, there is not a lot of sunshine in the average March, so even though the temperatures are warm enough for the growth of warm-season grasses, the available light for photosynthesis restricts the growth.

Hilo, Honolulu, Miami, and Sanya have similar temperatures in March, but there are more than 100 hours more hours of bright sunshine at Honolulu and Miami than at Hilo or Sanya. I spoke with Dr. Larry Stowell of PACE Turf about sunshine, photosynthesis, and the distinctiveness of weather in many parts of Asia in this YouTube video.