Field day poster: 5 grass varieties, 3 levels of salinity, and a month to grow-in -- or not

This poster for today's field day describes what happened when we planted five grass varieties as stolons and then supplied irrigation with different amounts of salt in the water. I think two things might surprise you. First, some of the grass varieties, including a particular manilagrass (Zoysia matrella), can reach full coverage in about one month after planting. Second, irrigation with salty water, so long as enough is applied, doesn't slow down the growth of many warm-season grasses.

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When the grasses can grow like this, it shows that managing the problems with water quality are closely tied to the quantity of water supplied. I will be talking more about this tomorrow when we are back for another day of seminars.

After 28 days, grow-in and salinity differences


I've been growing grasses in a plastic house with a lot of help from colleagues at the Thailand Institute of Scientific and Technological Research (TISTR). The idea was to see how these grasses grow in after being planted as stolons, and to see what happens when salt is added in the irrigation water. I'll be discussing this experiment at the field day in Chonburi next week.

The picture above shows the grasses that receive the irrigation with 330 ppm total dissolved solids (TDS), 28 days after planting. The seashore paspalum looks the best, and the nuwan noi manilagrass has grown-in almost as fast. The hosoba korai, which is a beautiful grass once established, still hasn't covered much of the pot.

Another thing I've found interesting is measurements of salinity in the soil with the new TDR-350. All the pots are supplied with the same quantity of water. But different sets of pots get different amounts of salt in the water.


The soil salinity in these pots is changing depending on which irrigation water is applied. That's just as expected.

For more about the TDR-350, see this webinar.


Grow-in potential

These pictures were taken 28 days apart. Here's what the grasses looked like yesterday, on February 24. That was 4 weeks, exactly 28 days after planting.


On 27 January, five different grass varieties were planted from stolons. The grasses, shown from left to right, are:

  • manilagrass (nuwan noi)
  • tropical carpetgrass (yaa malay)
  • seashore paspalum (salam)
  • manilagrass (hosoba korai)
  • bermudagrass (Tifway 419)

For the first 10 days after planting, all the grasses were irrigated with 330 TDS (total dissolved solids, in units of ppm) water. For the next 18 days, the grasses shown above were irrigated with 4,500 TDS water.

The planting rates for the stolons ranged from 99 g/m2 for the nuwan noi to 312 g/m2 for the yaa malay. This is the mean mass for the stolons planted in the pots. We cut the stolons into 10 segments with 3 nodes each and then weighed them and planted them; each 0.02 m2 pot was planted with 30 nodes (1,500 nodes per square meter).

This is what the pots looked like immediately after planting, on January 27.


I think this is interesting for two reasons. One, this gives some indication of the grow-in rate (and relative rates) of various grass varieties. Second, this shows the tolerance or not of the grasses to different salt levels in the water.

One set of grasses is getting water with salt (TDS) at 330 ppm, the one pictured are getting 4,500 ppm, and another set are being irrigated with 9,000 ppm.

I'll be talking about this, and showing some of these grasses, at the upcoming Sustainable Turfgrass Management in Asia conference.

Tropical carpetgrass on putting greens

Tropical carpetgrass (Axonopus compressus) can tolerate low mowing, even down to putting green height. Here it is invading a seashore paspalum (Paspalum vaginatum) nursery green.



Even though carpetgrass can grow at putting green heights, I don't recommend it for greens. In the locations where carpetgrass can grow, manilagrass (Zoysia matrella) can too, and I prefer manilagrass putting surfaces. Why? Manilagrass has a finer leaf blade and I expect the ball roll will be more predictable across manilagrass than across carpetgrass.

Carpetgrass on fairways -- I like that -- especially when mown at about 8 mm. And in the rough, under shade trees, tropical carpetgrass is the best choice in a tropical environment. These photos show more.


Does sandcapping affect playability? And does species selection?

I get to talk about two of my favorite topics today. In our 1 day seminar on designing, building, and maintaining golf courses, course architect Paul Jansen will be speaking about 3 main topics:

Where do I come in? I'm going to hone in on the ground contours part, and discuss how the soil and grass conditions affect how a ball will bounce and roll. One can design and build all these great features, but if the sward isn't right, the playability won't be either.

A quick summary of my thesis is this -- sandcapping ain't so great because once one introduces a sand profile, the organic matter must be managed or it will fail. That happens by default for putting greens -- usually -- but almost never on 10++ hectares of fairway turf. And using grasses that don't die allows one to apply less N and water. That leads to firmer surfaces that are better to play on when one wants ground contours to be interesting.

Here are three ways to follow along.

First, my presentation slides are here:

Second, I shared a 2 page PDF handout at the seminar. Download it here.

Third, the above slides and PDF, along with links to all the articles and the video from the presentation, are in this online handout. For convenience, I reproduce all those links here:

What good are contours if grabby grass grounds gravity?

Ground contours on the Old Course, St. Andrews

It's a grim outlook for ground contours on golf courses if the playing surface doesn't allow the ball to bounce and roll. On Sunday, I'll be talking about this as it relates to tropical Southeast Asia -- if one wants to have surfaces on which a golf ball is going to bounce and roll, what grasses are preferable, and what type of soil conditions do we need?

This is part of the Design, Build, and Maintain: a different way? seminar with Paul Jansen and Pirapon Namatra.

For a preview of my main points, see these two articles:

I'll be sharing some recent data, observations, and calculations, but those two articles give a good preview of the case I will make, and if you are attending the seminar, I hope you will read those articles in advance. If you are not attending the seminar, you'll probably like the articles anyway.

Yes, a running sward is quite possible in the tropics -- Plutalaung Royal Thai Navy Golf Course

And this too:

More about grasses on golf courses in Thailand: a Christmas Eve miscellany

Sunset_banyanGolf in Thailand at this time of year is really pleasant. I often use the words clement and salubrious, with additional modifiers, to express just how pleasant I find it.

Over the past 20 days in Bangkok, there has been no rain, and the temperature has ranged from 19 to 34°C.

I've written about the grasses one finds here, and I have also put together this photo gallery of the typical grasses. Most putting greens are hybrid bermudagrass, and after that comes manilagrass, and there are comparatively few courses with seashore paspalum greens.

Through the green, the percentage of courses with bermudagrass goes down, and the percentage with manilagrass and seashore paspalum comes up.

Turfgrass @ Thailand

At the Sustainable Turfgrass Management in Asia 2015 conference, we will be talking about these grasses, and we will have a pre-conference seminar in which we discuss the design and construction of golf courses in Southeast Asia.


It hasn't rained in Bangkok for 20 days, yet on the seashore paspalum fairways I played today, this was the result from multiple shots that landed in the fairway: debris (organic matter, or mud?) on the ball.

2014-12-24 13.50.15 2014-12-24 11.20.57 2014-12-24 11.38.52
I think the cause of this is related to the grass species. In Southeast Asia, when one does not keep the soil wet, seashore paspalum will eventually be overtaken by better-adapted species that thrive in drier soils. So seashore paspalum fairways must be kept really wet if the grass is to persist. One can topdress with large amounts of sand to minimize that problem, but that is really expensive.

A recent post on about seashore paspalum had some interesting comments from golf course superintendents and golfers and architects about this species. The consensus -- it requires a lot of inputs and can be very expensive to maintain.

I've got lots of ideas about grass selection and construction methods (especially sandcapping of fairways) and will be working on developing those for discussion at the upcoming conference. 

Tropical carpetgrass part 2: ugly duckling or swan?

When I wrote about tropical carpetgrass being an unappreciated grass, the conversations (1 & 2 & 3) that ensued showed a mixed response. Some people really like tropical carptegrass (Axonopus compressus), and others have no use for it.

Tropical carpetgrass on a golf course fairway in Singapore

It was rightly pointed out that in a a subtropical environment, tropical carpetgrass will not be ideal throughout the year, especially when it is cool. And like other grasses, there will be issues with drought tolerance, and traffic damage, and so on. Where this species is really well-adapted is in tropical climates that receive more than 1,000 mm annual precipitation; one wouldn't want this grass where precipitation is less than 800 mm. It is not a perfect grass, even in the tropics, but no grass is.

Tropical carpetgrass through the green at Chumpon, Thailand

So why do I persist in writing about tropical carpetgrass? Because for many tropical sites, this is the grass that should be used, and it has some very attractive characteristics that are especially relevant to the way I think about turfgrass management. When possible, I think we should manage turf with a minimum amount of inputs. Tropical carpetgrass, more than other species, can be maintained as a multipurpose turfgrass with the fewest inputs.

Last year I was interviewed by Matt Adams on the Fairways of Life radio show. You can listen to the interview here.

07.09.13 INT ARCHIVE Fairways Of LIfe Micah Woods_3592772

I was expecting Matt to talk with me about tournament preparation and golf and grasses around the world. Instead, he started by asking about maintenance inputs and grass selection:

Today more and more, there is pressure upon every golf facility in terms of how they maintain the golf course – the general line that we're hearing is that golf courses need to embrace more of the brown because water is at such a premium anywhere and everywhere around the world.

Then he asked, how can the type of grass chosen help us out in terms of maintainenance cost and availability of water? Rather than talking about using more resources and spending more money, the focus at the global level is to use less resources in turfgrass maintenance. 

This was also a prominent theme of Don Mahaffey's recent conversations at Golf Club Atlas (first interview, second interview). These are really good discussions about what golf course maintenance should be about, and I highly recommend taking the time to watch both of them in their entirety. In the second video, Don said something that is very applicable to turf management: 

We cut our maintenance expenses greatly, because we just focused on what's good for golf, and interestingly, no one complained.

Tropical carpetgrass fairway at Phuket, Thailand

With tropical carpetgrass, in a tropical climate with annual precipitation of at least 800 mm, and preferably with 1,000 mm or more, this grass requires only mowing. It can be maintained without fertilizer or pesticides, and irrigation is only required if one wants to make the grass green, or if the turf is to be heavily trafficked with golf carts.

There will be many golf courses or turf managers that prefer to grow and manage a grass that has different characteristics. But let's not forget about the many good characteristics of the multipurpose tropical carpetgrass. As the recent research from Trinidad and Nigeria demonstrates, this species has a number of advantages compared to other turf species in a tropical environment.

Tropical carpetgrass lawn in Ayutthaya, Thailand

An unfortunately underused and usually unappreciated grass

What is this underused and unappreciated grass? It is tropical carpetgrass (Axonopus compressus), the species that C.V. Piper, the first chairman of the USGA Green Section, wrote about as "the best of all grasses in the South for fairways." Piper added that:

It makes a dense, uniform turf even on pure sands and the leaves are stiff enough so that the ball is always well off the ground. The only other grass to compete with it is Bermuda; but under conditions where both will grow, carpetgrass makes far superior turf.

Tropical carpetgrass is the climax species as a managed turf in humid tropical climates. But it is barely mentioned in turfgrass textbooks, probably because the authors have focused primarily on the grasses in common use in the United States.

This is unfortunate, because tropical carpetgrass has a number of advantages as a turfgrass compared to species such as bermudagrass (Cynodon) or seashore paspalum (Paspalum vaginatum) that are sometimes planted in tropical environments. For example, it is possible to maintain tropical carpetgrass with no supplemental fertilizer, no irrigation, and no pesticides. In fact, that would be standard maintenance for tropical carpetgrass in many places – mowing, and not much else.

With these advantages compared to other grasses, it is encouraging to see two recent papers that have investigated some characteristics and performance of tropical carpetgrass.

Springer et al. compared bermudagrass, zoysiagrass, and tropical carpetgrass (they use the name savannahgrass for Axonopus compressus) at the University of the West Indies. They measured how much these grasses grew, and what quality they produced, when subjected to drought stress, waterlogging, and soil compaction. This was done in soil and in soil profiles with a surface sand layer to simulate the effects of sand topdressing.

Tropical carpetgrass through the green on the East Course at Wack Wack Golf and Country Club in Manila, Philippines

The full paper, Comparative Evaluation of Common Savannahgrass on a Range of Soils Subjected to Different Stresses I: Productivity and Quality, shows that tropical carpetgrass (savannahgrass) generally performed better in the growing environment of Trinidad than did the bermudagrass or the zoysiagrass. Averaged across all the stress treatments, tropical carpetgrass had the greatest clipping yield and the highest chlorophyll index. Zoysiagrass had the highest visual quality averaged across all stress treatments, with carpetgrass just behind, and then bermudagrass having the lowest visual quality.

Springer et al. concluded that tropical carpetgrass "showed a higher level of tolerance to applied stresses and warrants greater attention as a potential turfgrass under tropical conditions." 

Tropical carpetgrass provides a full turf cover in heavy tree and structural shade at Bali, Indonesia

In Nigeria, Oyedeji et al. investigated tropical carpetgrass and other local grasses. Their paper, Performance of Some Local Nigerian Turfgrasses in Sole and Mixed Stands, shows data that again make a strong case for tropical carpetgrass as a turf in that climate. Compared to other grasses, tropical carpetgrass performed well, especially in the recovery after 2 weeks of daily trampling with soccer boots.

Unirrigated carpetgrass during the dry season at Hua Hin, Thailand

In a tropical climate, it is hard to find a grass that outperforms tropical carpetgrass. One of its advantages as a turfgrass is its adaptability to a range of mowing heights. Tropical carpetgrass can be maintained with almost no inputs, except for mowing, and in addition to that, it can be mown at heights from 3 mm to more than 100 mm. 

A patch of tropical carpetgrass on a manilagrass green maintained at 4 mm in Chumpon, Thailand

How I came to have a Nittany Lion on my lawn in Bangkok


Thanks to the Penn State Turf Club, I received a Nittany Lion in today's mail. 

The Club selected our (Gelernter, Stowell, and Woods) article from the December 2013 issue of Golf Course Management for their Article of the Year Award.


We wrote Documenting your progress toward sustainability to

"help you and your facility measure and communicate concrete progress toward reaching sustainability goals ... 

Without the ability to measure it, sustainability remains a mushy, confusing and frustratingly unobtainable goal. Without quantification, evaluating the achievement of sustainability goals becomes wholly subjective — in the eye of the beholder. Although you may think you’re doing a great job, you have no way to communicate it or to prove it, unless you have some way to measure and document it.

In this article, we present several simple monitoring approaches that can help take the mush out of sustainability, and instead treat it as a measurable, science-based agronomic phenomenon. All of these procedures can easily be put into practice at your facility."

I'm thrilled that this article has been so well-received and that the Penn State Turf Club saw fit to choose this article for their award. Thank you!