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February 2014

One more look at accumulated difference in growth potential and overseeding

predicting optimum overseed date at Shanghai

After I shared this analysis of accumulated difference in cool-season and warm-season growth potential as a way to identify potentially optimum dates for overseeding, I've been able to obtain some more daily data from a range of locations: Dubai, Shanghai, Scottsdale, Antalya, Palm Springs, and Orlando. With these daily data, I've made charts to show the striking change as temperatures change from favoring growth of warm-season grass to favoring cool-season grass.

Larry Stowell from PACE Turf suggested I look at this accumulated difference plotted against time. As you can tell from my recent posts (1, 2, 3) on this topic, I've found it fascinating!

cool-season and warm-season growth potential at Orlando, 2013 cool-season and warm-season growth potential at Palm Springs, 2013 cool-season and warm-season growth potential at Scottsdale, 2013

It is an interesting way to look at potentially optimum dates for overseeding. I'd be interested to hear from turfgrass managers about the timings and relative growth predicted by these models. Do these inflection points on the charts correspond with the relative growth of cool-season and warm-season grasses at these locations? Full details of these calculations are available in this document: another way to look at turfgrass growth potential and overseeding.

temperatures and growth potential at Antalya

New motion chart to look at relative growth potential of cool and warm season grass

Motion_chart_inflectionThis new customizable motion chart looks at relative growth potential of cool-season and warm-season grasses based on World Meteorological Organization climatological normals data for six cities: Delhi, Dubai, Naha, Orlando, Phoenix, and Shanghai.

The precision of daily estimates, as shown in these charts for Kashima, is much better. This motion chart based on monthly climatological normals is only showing general trends, rather than identifying specific weeks in which overseeding might be most successful. There is still a lot of data and useful information to be extracted from this type of chart.

Growth Potential, Inflection Points, and an Optimum Date for Overseeding

Gp_overseed_inflectionLast year I showed cool-season (C3) and warm-season (C4) growth potential (GP) in relation to overseeding timing in Japan and in Dubai. Larry Stowell from PACE Turf suggested I look at another way of representing the growth potential. He said that if I would plot time on the x-axis, and the cumulative sum of the difference between C3 GP and C4 GP, I would see something very interesting related to the transition from good warm-season weather and good cool-season weather.

I've looked into this by analyzing the daily C3 GP and C4 GP using weather data from the past 15 years at Kashima, Japan. Read the report and see the charts here.

Are the MLSN guidelines too low?

Since the development of the MLSN guidelines (a joint project of ATC and PACE Turf) in 2012, I’ve had the opportunity to write about and to discuss these guidelines for soil nutrients with many people. One of the questions that I’m asked regularly involves the use of a temperature-based growth potential to estimate nitrogen requirements. 

PACE Turf, who developed the turfgrass growth potential (GP), have prepared a useful document that can help turfgrass managers get started with GP calculations for their site. Yesterday I shared this .xls spreadsheet, with the necessary equations embedded, on Twitter.

In response to that post, I was reminded of an important concern that I am sure many people have related to the MLSN guidelines.

That is, are these new MLSN guidelines, being substantially lower than conventional guidelines, causing nutrient recommendations to be so low that turf quality may suffer? At first glance, it may seem that this could be the case. 

Gcm_jan_2014But if we look at how the MLSN guidelines were developed, and at how they can be implemented, the chance that turf could suffer from the use of these guidelines seems unlikely. I think it highly improbable that “someday someone will lose grass trying to hit your numbers,” as was suggested in the Twitter discussion. These five points explain why: 

  1. The MLSN guidelines were developed from a database of more than 17,000 soil samples taken from good-performing turf. In each of those 17,000 samples, no matter the level of a nutrient in the soil, the grass was healthy. From those samples, we evaluated the distribution of various soil nutrients and chose a 10% threshold for the guideline. That is, we chose a level at which 10% (more than 1,700 sites) of the samples had good-performing turf at levels below the MLSN guideline for a specific element. This serves as a buffer against inadvertently setting the guideline too low. 
  2. Grass won’t take up more nitrogen than is applied as fertilizer, and nitrogen (N) controls the demand and uptake of other nutrients. This allows us to estimate how much of each element will be used by the grass, and consequently depleted from the soil, based on how much N is applied.
  3. We recommend keeping nutrient levels at or above the MLSN guidelines. We can make some calculations, based on the MLSN guideline in the soil, and how much of an element is being used by the grass, to ensure the nutrient levels always remain above the MLSN guideline.
  4. The word “minimum” is in the guidelines. And this can lead one to think we are striving to apply the minimum amount of nutrients. In a sense, we are. But the process we use involves making an estimate of the maximum amount of an element (K, P, Ca, Mg, S) that the grass can use, and ensuring that that amount is supplied to the grass in more than adequate amounts, either from the soil, or by application of that element as fertilizer.
  5. Because the MLSN guidelines are based on a conservative subset of samples from good-performing turfgrass sites, and because utilization of the guidelines involves making an estimate of the maximum amount of each element the grass can use, rather than “lose grass” using these guidelines, I am confident that turfgrass managers will see equal or improved turf quality with the use of these new guidelines.

For additional information on the MLSN guidelines and this method of estimating turfgrass nutrient use and nutrient requirements, see:

ATC video and korai greens featured on R&A Golf Course Management

Zoysia_putting_proofThe proof is in the putting when it comes to zoysia putting greens, as explained in this new update on The R&A's Golf Course Management site.

Fine-bladed Zoysia matrella is utilized on hundreds of golf courses in East and Southeast Asia (and on some courses in the southern USA) as a putting green grass. Known as korai in Japanese, and as manilagrass in English, this species is especially well-adapted to low mowing heights in shaded areas. 

This video shows the most famous course in the world with korai greens – the Fuji Course at Kawana Hotel – and the ball roll on korai greens at Keya GC in Fukuoka.

More analysis: Twitter followers

Twitter follower analysisYesterday I shared 4 charts showing a summary look at the Twitter accounts following @asianturfgrass.

In response to many questions about these data, I have made a few more charts (11 actually) and have included some explanatory text and links in this new document: twitter follower analysis.

For simplicity, I wrote this as an R Markdown file, so the final result is a web page (html file) with the charts embedded in the page.  

Other documents I have made using R Markdown include:

Four charts: Twitter accounts that follow @asianturfgrass


Have you ever wondered about Twitter followers and which accounts stand out? Or how the #GIS14_Turfbowl tweet rally was counted? I think it is interesting to look at some of these things, and with the Twitter API and streaming API, it is possible to obtain and study a tremendous amount of data.

I've been looking into this in my spare time this week, trying to explore some of the available data, and I made these four charts that show a few things about the accounts that follow @asianturfgrass; these data were obtained using the ScraperWiki Twitter tools, and the charts were made using ggplot2 in R.

As of 15 February 2014, there were 1350 accounts following @asianturfgrass, and the greatest number were created in 2011. Incidentally, the @asianturfgrass account was started on 1 January 2011. For the most part, we can expect that twitter accounts following @asianturfgrass will be interested in research, advice, and teaching about turfgrass -- in short, interested in turfgrass information.

I had thought that there may be an increase in accounts opened in 2012 and 2013 from 2011, as it seems that more turfgrass managers and turf companies are using Twitter. However, for my account, the plurality of follower accounts were created in 2011.

 Of the accounts following me, I looked at their follower to following ratio. That, I thought, might give some indication of just how influential or famous that person or company is.


The chart above shows the 15 accounts following me with the highest follower:following ratio as of today. And it is certainly a who's who of the turfgrass industry, from tournament courses to turfgrass researchers to famous consultants and superintendents. 

For the two charts below, you will want to click on the image to see at a larger size. They both show the same thing, the number of tweets from an account on the x-axis, and the number of followers of that account on the y-axis. The first one shows all of the accounts following @asianturfgrass as of today, and the second one shows only those with less than 20000 tweets and less than 7500 followers. That is, it zooms in on the data.


We can see that the vast majority of accounts are bunched in the region with less than 2500 tweets and with less than 1000 followers. The accounts that stand out, then, must be exceptional in some way. For an account to stand out from the pack, using this scatterplot, either the account sends a lot of tweets, has a relatively large number of followers, or both.


For an interesting look at the entire scope of Twitter accounts, see Tweets Loud and Quiet by Jon Bruner.

How does a ball roll on a zoysia green?

Hard at work in Fukuoka

Posted by Micah Woods on Monday, August 26, 2013

Last year I volunteered at Keya Golf Club during the VanaH KBC Augusta Golf Tournament. I collected data on putting green performance, and I mowed fairways.

With all the korai greens (this is Zoysia matrella, common English name is manilagrass) in Japan and in other parts of Asia, this is the only tournament on the Japanese men's tour played on korai greens each year. I wanted to see how the ball rolled on korai greens prepared for a professional tournament.

In this video, I introduce the world's most famous course with korai greens -- Kawana Hotel's Fuji Course, ranked in the world's top 100. And I show how the ball rolls on korai greens by demonstrating the R&A's Holing Out Test with a Greenstester. Actually, I was behind the camera, and course superintendent Andrew McDaniel was using the Greenstester. Follow him on twitter to see how he manages korai greens and to discover a lot more interesting information about turf management in Japan.

A fun video and a big thank you

I didn't go to the Golf Industry Show this year, so when I found out I was selected by Golf Course Industry to receive the John Kaminski Award for Leadership, I made this video to say thank you.

And to everyone who has written to congratulate me, I say "thank you" again here. I really enjoy studying and learning new things and then sharing that information. To be recognized on a global stage for what I do - and enjoy so much to do - is quite an honor.

Monthly Turfgrass Roundup (January 2014)

In case you missed them, these articles and links from the past month are likely to be of interest to turfgrass managers in Asia:

Registration is now open for Sustainable Turfgrass Management in Asia 2014, at Pattaya on 10 to 12 March.

Just what the grass requires article on MLSN guidelines in GCM.

The MLSN guidelines page with links to videos, technical data, and the project Facebook page.

I gave these presentations in Pennsylvania about turfgrass nutrient use and the Park Grass Experiment.

Rothamsted Research provide this data-filled page on the Park Grass Experiment.

This handout provides a lot more info to supplement the nutrient and Park Grass topics.

Jon Wall went to Nepal and shared some amazing photos of the Himalayan Golf Club. For example:

Jason Haines wrote a detailed post on fertilizer sustainability in action.

The 2014 edition of chemical control of turfgrass diseases by Vincelli and Munshaw is a must-have reference for turfgrass managers.

Sentosa Agronomy shared this photo of their equipment fleet. Pretty good for 36 holes!

I spoke in Korea about a modern method for determining turfgrass nutrient requirements.

The slides for that presentation are available here:

I made a new climate chart with data included for cities such as Kunming, China; Victoria, Canada; and Portland, Oregon, USA.

Application of bicarbonate can increase phosphorus availability to plants.

For more about turfgrass management in Asia, browse the many articles available for download on the ATC Turfgrass Information page, subscribe to this blog by e-mail or with an RSS reader - I use Feedly, or follow @asianturfgrass on Twitter. Link and article roundups from previous months can be seen here.