Viridescent - the Asian Turfgrass Center blog

The Difference in Leaf Temperature Between Wilting and Transpiring Grass

Today was an especially hot day at Bangkok. I went out for lunch, and when I was driving home I noticed that the thermometer on my dashboard was indicating an outside temperature of 42°C. Upon arriving home, I checked the official temperature, found it to be 38°C, and I promptly went outside with my infrared thermometer to measure the surface temperature of concrete and of grass. See the above image at full size here.

These measurements were made at 14:00. The concrete measured 53.6°C, about 15°C above the air temperature. Manilagrass (Zoysia matrella) wilting in the sun had a similar temperature, 48.8°C, more than 10°C above the air temperature. Meanwhile, manilagrass and carpetgrass (Axonopus compressus) in the same lawn, in areas with adequate water so the grass could transpire, had leaf temperatures ranging from 1.8°C below to 1.2°C above the ambient air temperature.

As part of a putting green performance data research project, I've collected leaf temperature data from hundreds of greens across multiple grass species in many countries. As of today, I've measured the surface temperature 802 times. If you are interested in reading more, these data are summarized beginning on page 21 of this report. It has been my observation that in conditions of full sun, minimal wind, and adequate plant water status, meaning the grass leaves are not wilting, no matter how hight the ambient air temperature, the leaf temperature will generally be within 1°C or 2°C of the air temperature. Have you ever measured anything different?

For those more familiar with °F than °C:

38°C = 100.4°F

53.6°C = 128.5°F

Turfgrass Notes From Korea

I was at Korea last week, where I visited six different golf clubs. Two were 18 hole facilities, one of which is under construction, one has 9 holes and is open 24 hours a day for half the year, two have 36 holes, and one has 72 holes.

That is Sky72 Golf Club, adjacent to Seoul's Incheon Airport, and as is typical of many courses in Korea, the course is lighted so that rounds can begin before sunrise and continue into the middle of the night. Two of the courses at Sky72 do well over 100,000 rounds per year, and that amount of traffic brings with it certain challenges.

There is of course the challenge of just getting the maintenance work done, but also the wear from all the traffic is severe. This is especially a challenge when zoysiagrass (Zoysia japonica) is used, as it so often is because of the climate, because there are less than six months of growth for zoysia in Korea.

At the beginning of spring, we can see in the photo above that the creeping bentgrass green has excellent grass coverage, but the zoysiagrass surround at the back of the green has been worn completely away through traffic during the winter. And the traffic makes for some unusual maintenance on bentgrass greens, where the hole location is changed multiple times per day. This is usually about every 80 to 100 players, or up to six times a day, I was told, at courses such as Korea Public GC, which hosts about 110,000 annual rounds and is open 24 hours a day from May to November. 

Greens of course require relatively high rates of nitrogen when they receive so much traffic. I've written extensively about the growth potential and how it can be used to predict nitrogen requirements. Calculating the cool-season growth potential (GP) for Seoul and estimating a monthly nitrogen use of 3.5 g N/m² when the GP is 1, we get an estimated annual use of 18.1 g N/m². But the busy courses are using, generally, 30 to 40 g N/m², to achieve the necessary growth rates to recover from traffic of more than 100,000 golfers each year.

During construction, it is customary to plant zoysia using stolons embedded in biodegradable nets that are rolled out across the fairways. After just visiting sod farms in the United States and finding that zoysia sod was selling for just over $3/m², it was interesting to note that these zoysia rolls in Korea are the same price, and the installed price, including a layer of sand topdressing, is close to $5/m². Once the rainy season and the hot weather of summer comes, this grass will fill in rapidly, and the fairway pictured above will be ready for a soft opening by October.

I saw cool technology too. At Golfzon County Sunwoon, I played 18 holes, the caddy kept our score on a tablet computer and recorded the number of putts for each hole, and she also took photos of our group on the course. When I returned to the clubhouse, I simply entered my locker number into a kiosk, and the scorecard was printed with a photo from our round, the hole by hole score, and the number of putts I had taken. It looks like I've got some room for improvement!

But that could be checked too, for there were two holes on which a video camera recorded my tee shot, archiving the swings on a website for my viewing at a later date as a record of the round, and immediately viewable on the in-cart tablet computer through the on course WiFi network. There is really some cool technology involved with these systems, and it is something that made my round of golf more fun than it otherwise might have been. 

Related articles

Turfgrass Nutrient Requirements and Fertilizer Choice

Using Waterfall Charts to Look at Soil Nutrient Levels: potassium as an example

How Much Potassium Does Grass Require?

Turfgrass Management on a Different Scale

Manilagrass Tees and Divot Problems, Fact or Fallacy?

Yesterday I shared this photo from Takarazuka Golf Club near Osaka. I mentioned that the manilagrass (Zoysia matrella) tee, even though it is on a par 3 hole, and even though the course has been open and busy for the past five months, five months in which the grass has been dormant, we see that the condition of the turf is still quite suitable for golf. And that is after five consecutive months of no growth.

I pointed this out because I know manilagrass can provide a superb playing surface in tropical Southeast Asia, even on tees, but I have often heard objections to the use of manilagrass, especially on tees, because of its supposed slow recovery from divots. I believe that is a fallacy, certainly in tropical Southeast Asia, and I think the situation with manilagrass and tees in Japan can inform us of a great deal on this particular subject. 

After more than four months of dormancy, a tee at Hirono GC near Osaka

Japan has about 2,400 golf courses, of which the tees are overwhelmingly manilagrass, which is called korai (コウライ) in Japan. In a recent survey of grass types on golf courses in Japan, more than 75% had manilagrass tees. So we are looking at about 1,800 golf courses in Japan with manilagrass tees. And the climate is such that the manilagrass will go dormant sometime in November and will start to grow again in April. The dormant period for manilagrass in most parts of Japan will be five to six months.

Golf is a year-round and all-weather sport in Japan. I've written about the ordeals of greenkeepers in removing snow so courses can open, and courses will be open all through the year except in the northern and mountainous regions that have extended snow cover.

The courses are played extensively while the manilagrass is dormant, but the grass survives, the playing surfaces are acceptable, and the divots, which occur month after month through the winter with no recovery at all, do not become a major problem.

A manilagrass tee on a par 3 at Keya GC in late March, photo courtesy of Andrew McDaniel

In fact, there is plenty of turf remaining on the tees, even at the end of winter, and once the weather warms up, and the manilagrass starts to grow, the tees have a full cover of grass with minimal divots. And during the growing season for manilagrass in Japan, there is little concern about divots on manilagrass tees at all. It's just not a major problem. The tees get beat up a bit in the winter, but they don't fail, and they are fine for the rest of the year.

If manilagrass works on over a thousand courses in Japan, and only grows for part of the year, and still produces a fine surface for tees, shouldn't we expect it to work well in a tropical environment, where the temperatures are nearly at an optimum for manilagrass growth 365 days a year?

A fine-bladed manilagrass tee on a busy par 3 hole at Muang Kaew GC in Bangkok; about 72,000 rounds a year are played at this course

When we do look at manilagrass tees in Southeast Asia, we find that the turf is generally just fine. In fact, I would argue that the average manilagrass tee performs better than the average Cynodon tee. And manilagrass can outperform seashore paspalum too.

Seashore paspalum at left is damaged by foot traffic at this busy course near Bangkok, while the manilagrass tee surface at right has much less traffic damage

Research conducted at the University of Arkansas has determined that manilagrass is more resistant to divots than are Cynodon species. In fact, divots from Cynodon species on average were almost 2x larger than were divots taken from manilagrass. So we can expect that there will be fewer (and smaller) divots on manilagrass tees. Another research project at the University of Arkansas found that some cultivars of manilagrass have divot recovery times equal to or faster than some cultivars of hybrid Cynodon. So we can have a situation with manilagrass of smaller divots to begin with combined with a recovery time very similar to Cynodon hybrids.

Shade and the Performance of Warm Season Grasses in Asia

Have a look at this image. It is an aerial view of Wack Wack Golf and Country Club, a 36 hole golf course in Manila. The West Course is on the left side of the image, and the East Course is on the right side. Do you notice a difference in the grasses?

View Larger Map View Bird's Eye

To me, the grass on the East Course looks greener and healthier than the grass on the West Course. And the grasses are different. The East Course has broadleaf carpetgrass (Axonopus compressus) fairways and manilagrass (Zoysia matrella) greens; the West Course is all hybrid bermudagrass.

Trees on the East Course (see below) throw shade everywhere, but the carpetgrass and manilagrass still thrive in these conditions. The bermudagrass does not.

This case study on The R&A's Golf Course Management site provides more details and photos about the benefits of using native grasses at Wack Wack. The aerial view shows just how well those native grasses perform in that environment.

Just down the road at Manila Golf Club, there is some incredible shade thrown across the course each morning by a row of 55 story buildings on the east side of the property.

In such heavily shaded conditions, manilagrass performs the best, then seashore paspalum, with bermudagrass (Cynodon) not doing well at all. In the photo below, I identify the manilagrass with my nose, and the bermudagrass test plots identify themselves - they are basically dead. 

In tree shade or in building shade in Southeast Asia, manilagrass performs exceptionally well as a fine turfgrass. But there is another type of shade, one that can block up to 75% of photosynthetically active radiation. That is the shade that comes from clouds. 

Last week, I took this photo at 10:51 in the morning. The sun was behind a cloud and the quantum meter has a reading of 498 micromoles of photosynthetically active light per square meter per second. That is less than 25% of full sunlight. The effect of clouds is not terribly important for cool-season grasses, and most textbooks ignore it, but this is a big issue for warm-season grasses.

I've studied and written about this and its relevance particularly to the conditions so common in East and Southeast Asia.

Click here to download How Much do Clouds Affect Photosynthetic Irradiance? Measures of Light at Thailand, Hong Kong, Vietnam, and Japan

From Indonesia in the south to Japan in the north, we see that manilagrass, and in the areas with average annual temperature above 22°C, carpetgrass as well, perform extremely well. Particularly in shaded conditions, which can be caused by trees, buildings, or clouds, these grasses outperform bermudagrass and seashore paspalum. 

Turfgrass in Catalonia: 3

After seeing so many grasses at the PGA Catalunya Resort, and then even more at Barcelona, I must say I was surprised again to continue seeing such a variety of grasses as David Bataller and I went botanizing at the Costa Brava and the Semillas Fitó turfgrass experimental station.

In addition to the ten turfgrass species I already listed from the Resort, a look at the grass around the revetted bunker reveals an eleventh - fine fescue. 

To those eleven species, I can add Stenotaphrum secundatum (above), which we saw thriving as a lawn grass in some parts of Catalonia, and also Zoysia matrella, which we saw on a few traffic circles.

At the Semillas Fitó turfgrass experimental station we saw seeded kikuyugrass and seeded Cynodon dactylon along with a variety of cool-season turfgrass varieties. I was especially interested in the Playa seed mixture which looked great on the research plots and contains seed from four different species: Cynodon dactylon, Festuca arundinacea, Poa pratensis, and Lolium perenne. 

And at Golf Platja de Pals, the first course on the Costa Brava, designed by Fred Hawtree, and site of the 1972 Spanish Open, the turf is almost all Poa annua, and one can even find pink snow mold (Michrodochium nivale) in the shaded areas there.

I think it is pretty amazing to see thirteen turfgrass species, all performing pretty well, and even in early December to see green Stenotaphrum secundatum and green Zoysia matrella and green Cynodon dactylon alongside Poa trivialis and Poa annua. If I had a lawn in Catalonia, I think I would plant the Playa mixture from Semillas Fitó myself, just for the novelty of having a mixture of warm- and cool-season grasses in the same lawn, and because the other types of Festuca arundinacea that I saw were performing very well. 

In Southeast Asia, there are just a few species of grass that work well as a lawn or as a sports turf. In northern Europe, there are just a few species that work. At Catalonia, I saw thirteen species, all growing, to some extent, very well. In Sydney, or in Brisbane, or in San Diego, or in Atlanta, we can have a wide range of species, but I don't think I've ever been anywhere where such a wide range of grasses were growing.

Related articles

Turfgrass in Catalonia: 1

Turfgrass Mystery: how was this bunker revetted?

Turfgrass in Catalonia: 2

A Report from Madrid: the 34th Spanish Greenkeepers Congress

Golf Courses and Turfgrass on the "Miniature Continent" of Gran Canaria

Turfgrass in Catalonia: 1

Occasionally I get to travel to places that have a tremendous variety of grasses. One of these is Hawaii – a wonderland of grasses. But at Hawaii it is a panoply of warm-season grasses. Recently I visited Catalonia, at the invitation of David Bataller, Golf Courses and Grounds Manager of the PGA Catalunya Resort. What I saw was really amazing! Almost every warm-season and cool-season turfgrass was growing in this region.

It is always interesting and a great learning experience to see so many types of grass. One thing that remains consistent about places where a lot of grasses, both cool- and warm-season species can grow, is this: these are among the most difficult places in the world to produce good year-round playing surfaces.

At this 36-hole facility, David manages primarily cool-season grasses, but there are also warm-season grasses – in fact, I counted ten different species of turfgrass, in total, being used on the property, plus lovegrass (Eragrostis) put to good use in many landscaping and out-of-play areas. In no particular order, they are:

• Lolium perenne (C₃)
• Zoysia japonica (C₄)
• Pennisetum clandestinum (C₄)
• Poa annua (C₃)
• Poa trivialis (C₃)
• Poa pratensis (C₃)
• Agrostis stolonifera (C₃)
• Cynodon dactylon (and Cynodon hybrids) (C₄)
• Paspalum vaginatum (C₄)
• Festuca arundinacea (C₃)

Why are there such a wide variety of grasses used for turf in Catalonia? If we look at a chart of growth potential through the year (Figure 1), it would seem that cool-season grasses would be a clear choice for this area. 

Figure 1. Temperature-based growth potential of C₃ and C₄ grasses based on climatological normals data for Girona, Spain.

The chart shows that the cool-season growth potential is higher than warm-season growth potential throughout the year. But what we find growing are both cool- and warm-season grasses. This is similar to a place like San Diego, California, where we can find seashore paspalum and bermudagrass and kikuyugrass growing alongside perennial ryegrass, Poa annua, and creeping bentgrass. 

The reason warm-season grasses perform well in this type of climate is because of water. Warm-season grasses have better water use efficiency than do cool-season grasses, and warm-season grasses generally have better salinity tolerance than do cool-season grasses. So in a climate where the evapotranspiration is higher than the precipitation, and where the irrigation water has some salt in it, warm-season grasses will compete well with and may even outperform cool-season grasses.

During the winter season, the warm-season grasses go dormant, as we can see with the Zoysia japonica on the bunker slope, but it is not cold enough for there to be any winterkill. 

There was even a local type of seashore paspalum (seedhead at right) that grows well in this area, and in fact some of the older golf courses near the sea in Catalonia have this native grass.

After the vist to PGA Catalunya Resort, my head was spinning. We had seen so many types of grasses, seen sunrises over the frost-covered courses, had discussed the soil and water salinity challenges, and tried to predict how certain grasses would grow at different times of the year. Maintaining fine turfgrass in a transitional climate, especially one without much precipitation, is really a challenge. 

Turfgrass at Gran Canaria: high season traffic, growth potential, salinity, and radio interview

During my visit to Gran Canaria, I visited all seven golf facilities on the island. It is interesting to consider how the different grasses are performing. Although Gran Canaria has an exceptionally salubrious climate for people, it actually can be a difficult place to manage turfgrass.

The main turfgrasses being grown on the golf courses are:

• kikuyugrass (Pennisetum clandestinum)
• seashore paspalum (Paspalum vaginatum)
• bermudagrass (Cynodon spp.)
• creeping bentgrass (Agrostis stolonifera)

The first three of these are warm-season grasses, meaning they grow most rapidly with an average temperature of more than 27°C. Creeping bentgrass is a cool-season grass, and it grows best at a temperature of around 20°C.

There are three interesting things that we can note related to the grasses and the temperature here. 

1. When we plot the temperature-based growth potential of cool-season and warm-season grasses based on climatological normals weather data at Las Palmas, we see that the growth potential for cool-season grass is higher than that for warm-season grass for each month of the year. For more about growth potential, see this article by Dr. Wendy Gelernter and Dr. Larry Stowell of PACE Turf.

Figure 1. The temperature-based growth potential for C₃ and C₄ grasses based on climatological normal temperatures from Las Palmas de Gran Canaria. 

2. The grasses on the golf courses of Gran Canaria are almost all warm-season, but the growth potential model predicts that the temperatures are ideal for cool-season grasses. Why is it that we find the warm-season grasses predominating?

It is because of water. The eastern and southern parts of the island, where the golf courses are located, receive very little precipitation. Supplemental irrigation is required to keep functional golfing surfaces, and that irrigation is both limited in supply and rather high in salinity. Some irrigation supplies on the island have an electrical conductivity of almost 4 dS/m. 

Warm-season grasses such as bermudagrass and seashore paspalum have lower water use rates than do cool-season grasses, and these warm-season grasses are also more tolerant of salinity. This allows the golf course turf to be maintained with a minimum of water. This benefit is enhanced by the rather cool temperatures during the winter months, and in fact, for seven months of the year at Gran Canaria, the warm-season grasses grow at less than 50% of their potential, which means they use less water. The relatively low growth potential for warm-season grasses mean they will use less fertilizer also.

3. The resort courses at the southern part of the island see high traffic during the months of October to April. This creates a challenge for greenkeepers because the very season at which traffic is highest is also the season at which the primary turf of bermudagrass or seashore paspalum has its slowest growth. 

 

Micah Woods, Alejandro Nagy, and Fernando Suarez on a seashore paspalum tee at Maspalomas Golf

 

As I spoke with greenkeepers around the island, and as I mentioned in my radio interview with Chicho Morales on Bajo Par Canarias, the most important thing in managing good turf on Gran Canaria is water. Applying the right amount of water to the turf, and managing the salts that are applied in the irrigation water, by leaching, will lead to the best possible turfgrass conditions. 

Listen to the radio show here, with extended comments from me starting at about the 10:00 mark, some good questions from host Chicho Morales, and translation and additional remarks on my visit by Alejandro Nagy and Daniel Carretero.

For more information, I wrote about the golf courses and grasses of Gran Canaria in this post, and you can see photos of the different grasses and golf courses at Gran Canaria here.

Golf Courses and Turfgrass on the "Miniature Continent" of Gran Canaria

I visited Gran Canaria and its seven golf courses this week, choosing this island in particular because of its many microclimates and consequently the chance to study a variety of grasses in different environmental conditions.

Location (in blue) of the 7 golf facilities on Gran Canaria

 I also have friends (*see below) on this island, which made it an even more appealing place to visit. The north side of the island sees more clouds, and the south side of the island has more sunshine, and in general, it is a rather dry island. At the airport, near Telde in the East, the average annual rainfall is 134 mm. Contrast this with Bangkok, where grasses, many of them the same as at Gran Canaria, grow in a climate with almost 1,500 mm average annual rainfall. In fact, at Bangkok, there are six months of the year, each of the months from May through October, that have average rainfall more than the 134 mm annual average at Telde.

That lack of rainfall makes irrigation crucial to the performance of any turfgrass as a sporting surface at Gran Canaria, and because almost all of the courses are irrigated with treated wastewater, which is rather high in salinity, careful attention to water quality is just as important as water quantity, as is choosing the grass species that can tolerate such salinity. 

At the seven golf clubs on the island, there are nine courses. Salobre is 36 holes, and Anfi Tauro has a short course. The grass breakdown is this. On greens, four courses are creeping bentgrass, four are seashore paspalum, and one is bermuda. Through the green, one course is kikuyugrass, four are bermuda, and four are seashore paspalum.

There is some Poa annua growing, mixed in with bentgrass on some greens, and as a weed in some fairways. I also saw some perennial ryegrass, although it was not thriving. And there was Stenotaphrum secundatum (St. Augustingrass in the USA, buffalograss in Australia) growing well in a few parks, but I did not see it on any golf courses.

At Real Club de Golf de Las Palmas, some unirrigated picon areas between tees and fairways have drought-tolerant bermudagrass growing in these dry conditions. The tees and fairways, which receive irrigation, are covered with kikuyugrass. A collection of photos are posted at Flickr (and below) where you can see the grasses and the golf courses of this diverse island.

*Alejandro Rodriguez Nagy, who arranged the schedule this week and introduced me to the greenkeepers at each course; Daniel Carretero, who played on the golf team at the University of Portland (my hometown) and worked at Augusta National GC where I met him during the 2011 Masters Tournament; and Oscar Sanchez, who I caddied for at Waverley CC when he played in the 1993 USGA Junior Amateur Championship.

Articles By and About Asian Turfgrass Center, in Chinese

Golf People magazine have just published my article entitled A New Way of Looking at the Weather (in Chinese) in their October issue. I first published this as a handout for the Sustainable Turfgrass Management in Asia 2012 conference, to supplement my presentation of the same title. See the handout in English here.

I've written other articles that have been translated into Chinese. The Chinese versions of these articles can be downloaded here:

The Right Work at the Right Time

Course Maintenance Standards

Turfgrass Information Resources

GCM magazine's profile article about Micah Woods was also published by GCM China and can be downloaded here. 

Turfgrass in the Ryukyu Islands: report on the special lecture at Ocean Expo Park

Just before typhoon #15, I traveled to Okinawa to deliver a lecture about Turfgrass in the Ryukyu Islands at Ocean Expo Park. And despite the approaching typhoon – now passing Okinawa with winds over 130 miles per hour and with waves 50 feet high – there were 101 people in attendance in a packed room to hear about the turfgrasses of these islands, what makes this such a challenging place to produce good turfgrass (low photosynthetic irradiance), and the four steps that one can implement to optimize turfgrass performance under these conditions. 

And people came not just from Okinawa, but also from Osaka, and from Nagano, from golf courses, city councils, landscape designers, engineers, agricultural scientists, to learn about turfgrass management in this part of Japan.

One of the things that was discussed was the climate, and I showed the climatological normals data for Naha and Ishigaki, comparing those cities to other cities where warm-season grasses are grown and demonstrating that there is less sunshine here, therefore making bermudagrass, with its high light requirement, a difficult grass to maintain in these conditions, with manilagrass, or St. Augustine grass, or broadleaf carptegrass, producing a better turf under the reduced irradiance of these islands. The presentation slides are available for download as a PDF here (14 MB).

I also prepared a handout for the lecture, and it is available for download here, also as a PDF file (600 KB).

Of course, with any lecture of this type, I am indebted to the translators, and Ocean Expo Park has excellent staff who translated the handout into Japanese, translated my lecture, and served as amazing hosts for my stay at Okinawa. We had a great time, and I'm looking forward to my next visit to Okinawa.