Viridescent - the Asian Turfgrass Center blog

Chemical Fertilizer Programs for Sand Based Rootzones - the 1 minute version

Last week at the Tennessee Turfgrass Association conference I gave a 30 minute presentation with the title Chemical Fertilizer Programs for Sand Based Rootzones. But this topic doesn't always require 30 minutes to explain - I like to distill this topic into the most important principles. There is plenty of experimental and empirical evidence to show that these four principles, if followed, will give excellent results.

1. Apply the right amount of nitrogen
2. Ensure soil pH is more than 5.5 and less than 8.3
3. Ensure soil potassium (as measured by the Mehlich 3 extractant) is kept above 50 ppm
4. Ensure soil phosphorus (as measured by the Mehlich 3 extractant) is kept above 35 ppm

The End (of the 1 minute version of this topic)

If you are especially interested in mineral nutrition for turfgrass or soil nutrient analysis for sand rootzones, you may want to read or watch some of these more lengthy expositions.

Simple Fertilization: Use the Nutrients Already in the Soil, from the Hawaii GCSA newsletter

PACE Turf Potassium Sufficiency Video, on Youtube

Soil Testing: It Does Not Have to be Difficult, on Youtube

Creating an Excellent Playing Surface: Managing the Plant, especially section 2 regarding nitrogen application

Does Potassium Fertilizer Really Increase Roots?, from TurfNet Monthly

And for those who really want to reduce P and K, consider the implications of The Park Grass Experiment and the Fight Against Dogma, written with Dr. Frank Rossi and published in the USGA Green Section Record

Potassium for Turfgrass: interview with Dr. Larry Stowell of PACE Turf

Dr. Larry Stowell and I recorded this video interview about potassium fertilizer for turfgrass. How much potassium is enough? How should you decide how much potassium to apply to meet the plant requirements, without wasting money by applying too much? Is potassium fertilizer necessary at all? Watch this video to find out, and check out PACE Turf for a wealth of valuable turfgrass information.

World Cities Plotted by Climatological Normals, November

This chart shows a selection of world cities, plotted by their average temperature, precipitation, and sunshine hours for the month of November. An interactive and customizable chart with the climatological data is available at this link.

How does November look? Well, at cities such as Bangkok and Mumbai, on average, it looks pretty good for warm-season grasses. The rainy season has ended, sunshine hours are way up, and average temperatures are still close to an optimum for warm-season grasses. The Barclays Singapore Open will be on at Sentosa in November. Temperatures are good for warm-season turf, but look at the sunshine hours! On average, there are only 125 hours of sun at Singapore during November. The Zoysia matrella fairways will be in superb condition, I'm sure, for they thrive in these conditions. The bermudagrass greens will be superb as well, but it takes a lot of careful work to maintain high-quality bermudagrass at Singapore, mainly because of the relatively low light conditions.

Eight New GC Seminar Articles Available for Download

I've uploaded eight articles to complete year three of the series I write about turfgrass science for Golf Course Seminar (ゴルフ場セミナー) magazine. There are now 36 articles from this series available for download.

マイカの時間 1 (Micah's Time, Part 1)

マイカの時間 2 (Micah's Time, Part 2)

マイカの時間 3 (Micah's Time, Part 3)

What are these articles all about? The eight articles just uploaded deal with reducing stress on the grass and developing a system of golf course maintenance based on controlling the growth rate of the grass.

The figure at right, from the October 2010 issue, shows the growth response of creeping bentgrass to increased nitrogen application, based on research by Kussow and Houlihan at the University of Wisconsin, and demonstrates that creeping bentgrass growth is perpetually limited by nitrogen application rate.

These articles also discuss how to evaluate the seasonal growing patterns and stress periods based on the growth potential model of Drs. Gelernter and Stowell of PACE Turf. The figure at right is from the November 2010 issue and shows the calculated growth potential for Tokyo based on average monthly weather data.

These articles are translated expertly by Mr. Yukio Ueno, and they are read by greenkeepers and course maintenance workers all over Japan. I'm writing the fourth series now, which is focusing on international case studies that will be of interest to Japanese greenkeepers.

ATC Articles Featured on Pitchcare Oceania

Have you seen the Pitchcare Oceania site? This online magazine has information about turfgrass management for golf and sports turf and this year has begun featuring selected articles from ATC.

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.

New R&A Golf Course Website & Case Studies

You are probably aware of The R&A's "Working for Golf" campaign and their active support for golf development around the world. Maybe you've been to the R&A-supported Sustainable Turfgrass Management in Asia conferences, held over the past few years at Thailand, Philippines, and Malaysia. The R&A's Golf Course committee have just this month unveiled a new web site, appropriately titled The Golf Course, that will be of interest to anyone involved in golf course management and development.

What do you find on the site? Relevant content, updated regularly, in the categories of playing performance, golfer expectations, turf management, economic performance, environmental stewardship, water resources, social responsibility, energy efficiency — the list goes on, all good topics.

Has anyone asked you about the fairy rings visible on the greens at Royal St. Georges during the Open Championship? I've been asked many times, and the best explanation I've seen is this article on The Golf Course site: "Provided the greens are mown frequently, as they are during The Open Championship, the growth stimulated by the extra nitrogen ‘fertiliser’ does not affect the smoothness of the putting surface and, therefore, has no adverse impact on play." The article goes on to explain how a team from the Sports Turf Research Institute conducted daily soil moisture measurements and other tests to assess playing surface performance, and it notes that "The R&A is far more concerned about the quality of how a surface plays than its aesthetics."

I've worked with Banyan GC in Thailand (pictured above) to prepare a case study about the use of drought tolerant (among many other beneficial attributes) zoysiagrass, and with Wack Wack Golf and CC in the Philippines (pictured below) to develop a case study on innovative renovation techniques and the use of native grasses. Wack Wack just hosted the Philippine Open on its shade-tolerant carpetgrass and zoysiagrass surfaces. Both case studies are now featured on The Golf Course.

Banyan GC case study (Thailand)

Wack Wack Golf and CC case study (Philippines)

Why is it so important to choose the right grasses, and why are these courses so notable for choosing the carpetgrass and zoysiagrass, native grasses that perform especially well in Asia? Have a look at the chart below.

We can choose Miami as a typical city for North American warm-season areas, and Kuala Lumpur as a city with typical conditions for Southeast Asia. You can duplicate this chart by going to the animated bubble chart and selecting just Miami and Kuala Lumpur, deselecting the other cities, and ensuring "trails" are on, and then clicking the "play" button. On the horizontal axis we have the average temperature, and on the vertical axis we have the average sunshine hours per month. These "trails" trace the temperature-sunshine combination throughout the year for each of these cities. One thing really stands out to me — these cities never overlap. There is not a month in the year, on average, when the temperature-sunlight combination at Kuala Lumpur is within the range of combinations seen at Miami. And vice versa.

On average, there is always less sunshine at Kuala Lumpur than there is at Miami. And the temperature almost never changes at Kuala Lumpur, while there is quite a bit of change at Miami. Even when it is the same temperature at Miami and Kuala Lumpur, there will be, on average, considerably less sunshine at Kuala Lumpur: just 50% to 75% of the sunshine hours we would have at Miami. These are, in short, completely different growing environments. 

And I would argue, and the success at Banyan GC and Wack Wack Golf and CC and other clubs throughout the region would support this, that the native grasses produce superb surfaces, are tolerant of low light from the massive tropical trees and the cloudy weather so typical of Asia, and that native grasses outperform imported hybrid bermudagrasses and seashore paspalum in many situations.

How Much Potassium Does Turfgrass Need?

Potassium is the mineral element found in the second-highest concentration in turfgrass leaves; only nitrogen is at a higher concentration. But how much potassium fertilizer is enough? Dr. Doug Soldat from the University of Wisconsin wrote a post for the Turf Diseases website entitled How I'd Manage Potassium on Cool-season Turf, and he has expanded on that in an excellent article in the May/June issue of The Grass Roots.

Dr. Soldat makes a quick review of when and how potassium is likely to provide improved cold, heat, drought, and wear stress. You might be surprised to find that the research results aren't very strong or conclusive in supporting the idea that high levels of potassium fertilization confer these increased stress tolerances to cool-season grasses. There is no doubt that potassium is an important mineral element, but if there is already enough potassium available to the grass, adding more doesn't seem to have much of an effect. For example, we can read in textbooks that more potassium will lead to a more extensive root system, but is that really the case? 

Does potassium fertilizer really increase roots?, I asked, in this article from TurfNet Monthly. My conclusion was that potassium fertilizer will do nothing to increase roots, and in fact may actually cause a decrease in rooting, unless the potassium was being applied to correct a potassium deficiency. Potassium application to turfgrass is likely to increase rooting only when it eleminates a potassium deficiency. I would classify a turfgrass soil as requiring additional potassium at about the 50 ppm level using the Mehlich 3 soil test extractant. If the soil is less than 50 ppm potassium, we might expect some response from a potassium fertilizer application. If the soil has more than 50 ppm potassium, the grass can almost certainly get all the potassium fertilizer it requires from the potassium that is already in the soil, and potassium fertilizer would be unlikely to influence turfgrass performance. 

New Calendar Page on ATC Website

I've added a new page to the Asian Turfgrass Center website with a calendar of selected turfgrass conferences and educational seminars that may be of interest to turfgrass managers in Asia. This is not a comprehensive list of events, but I will keep it updated with events as I become aware of them. If you would like me to add an event to this calendar, please send me an e-mail with details of the event.

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.

New Information on Diseases and Cation Exchange Capacity

I've been really busy in the past month, returning to Thailand after the exciting Masters Tournament, traveling to Singapore, Vietnam, and Sri Lanka, studying, and writing. Thanks to @daisukeiw who sent me the image above of the layout for my new series in Golf Course Seminar magazine. Pitchcare Oceania have just published a panel report on cation exchange capacity (CEC) and have featured some comments from me about CEC in sand rootzones and how it can be estimated most accurately by using an equation in which the only variables are soil pH and soil organic matter content.

I've also made some international updates to the Turf Diseases website. Some of my recent posts on that site are:

Large Patch Resistance of Zoysia?

A Cornucopia of Disease in Southeast Asia

Healthy Grass = Little Disease

Potassium, Hokkaido, and Snow Mold

Turfgrass Diseases in India

What is the Most Interesting Disease in the World?

Mites, a Corpse Plant, and Native Grasses

Large Patch on Zoysiagrass

More About Seashore Paspalum

A Most Unsightly Disease

The Wow Factor, Seashore Paspalum, and Dollar Spot