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December 2013
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January 2014

Climate charts, growth potential, and chart options

I've found it useful (and interesting) to study the climatological normals for locations around the world, and I have shared a number of charts containing this information at

One of the most useful plots for me is one that shows the combination of temperature and sunshine hours (light) throughout the year. Turfgrass managers have some control over nitrogen supply and plant water status, but they can't do much to modify temperature or sunshine. Therefore, turf growth is influenced by those factors, and we can compare locations by plotting light and temperature.

For example, we can see in this chart that Raleigh has similar temperature to Tokyo, although it gets slightly colder in winter at Raleigh and slightly warmer in Tokyo during summer. However, when it comes to light, Raleigh averages about 8 hours of sunshine during summer; in Tokyo the summer sunshine is 6 hours or less. Does this have some influence on ultradwarf bermudagrass performance and management? I think it must.


These are interactive charts, and one can modify which data are displayed. In this chart, I've looked at Atlanta and Tokyo, but now I've plotted C4 growth potential (GP) against daily sunshine. One can see that the sun in Atlanta is more than 8 hours a day when growth potential is at its peak. In Tokyo the GP gets higher than it does in Atlanta but the light is 50 to 75% of that available in Atlanta.


This guide to customizing the charts shows all the options, where one can click, and what can be changed at that tab.

motion chart guide

So we could, for example, show temperature plotted against growth potential to get an idea of how growth potential changes with temperature. And we can scroll through for each day of the year, and we can choose which cities if any are to be highlighted.


We could also show that as a bar chart, again setting the display for any date in the year.


To really make things complicated, have a look at these data as shown on a line chart.



The moving charts at were made using the googleVis package in R. Static charts were produced using the ggplot2 package. Climatological normals data shown on the charts are from the WMO data, or from national meteorological services. The Hong Kong Observatory have an easy-to-use website with climatological normals data from the WMO embedded for many world cities.

Winter turf nutrition seminars: Sky72 & Turfgrass Society of Korea

Korea1rI went to Korea this week to teach about turfgrass nutrient requirements and the new MLSN guidelines. I taught for 4 hours as part of the 2014 Sky72 Winter Seminar, explaining how these 5 principles can be used to ensure any turfgrass, anywhere in the world, maintained to any standard, can be supplied with just enough of each essential nutrient:

  1. The elemental content of fertilized turfgrass leaves is relatively constant
  2. The amount of nitrogen supplied to the grass controls growth and uptake of other nutrients
  3. A temperature-based growth potential can predict how much nitrogen the grass will use
  4. The grass cannot use more nitrogen than is applied as fertilizer
  5. The MLSN (minimum levels for sustainable nutrition) guidelines ensure that soil nutrient levels remain high enough to produce excellent turf conditions


Sky72 is the host of multiple professional tournaments each year and it was great to spend some time at this facility. We had lunch at the amazing Dream Golf Range, a circular driving range with hundreds of hitting platforms. It was (perhaps still is?) the world's largest driving range. If you've flown into Incheon, Sky72 is the course (4 actually) right at the airport. You may have seen this video produced by the course staff:

The next day, I was at the Korea Golf Industry show to speak with the Turfgrass Society of Korea about a similar topic.

Korea3rIn a presentation I called A Modern Method for Determining Turfgrass Nutrient Requirements, I explained how an estimate of nutrient use, combined with the MLSN guidelines, and with a measurement of the nutrient levels in the soil, allows a turfgrass manager to know exactly how much of each nutrient must be supplied. 

We can be confident that good performing turf can be produced in soils with nutrient levels at or above the MLSN guidelines. To ensure the soil remains at or above the MLSN guideline, we can determine the fertilizer requirement for any element by subtracting the amount present in the soil from the amount at the MLSN guideline added to the estimated harvest of that element by the grass.

See the slides from that presentation here:

It's here! Chemical Control of Turfgrass Diseases 2014

Ppa1_2014This reference guide by Paul Vincelli and Gregg Munshaw is updated for 2014 and is available for download from the University of Kentucky. 

Much more than just chemical control, the guide provides information on just about everything one might need to know about common turfgrass diseases, what may have caused the disease, and how it can be controlled. And there is a wealth of information about fungicides too. What is most amazing to me is that this much useful information can be delivered in just 24 pages! 

If you have already used this guide, you will want to get a copy of the 2014 version. And if you haven't used it, download it here. I think you will find it useful on more than one occasion this year.

Monthly Turfgrass Roundup (December 2013)

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

Grass selection and the right grass on this award-winning new course in Vietnam.

I posted 3 turfgrass mysteries in December: underwater grass, a mysterious line on the green, and a greenside spot.

Golf course architect Paul Jansen believes some golf courses would be much improved without any bunkers at all. He wrote more about this in a My View piece for The R&A:

Greg Evans wrote this article in Pitchcare about growth potential and taking greens that extra step.

Dave Oatis wrote about the utility of check plots in the Green Section Record.

Does dew removal help reduce Fusarium?

Grass report from Mauritius and slides and handouts from my presentation there.

Grass report from Dubai

I studied the website statistics and found the most viewed posts on this blog over the past years. In 2013, these are the top 5 and these complete the top 10.

These are the top 5 posts of 2012, 2011, and 2010.

I'll be writing a new column for GCM China.

I was in India for the first half of December for the Indian Golf Union greenkeeper education programme. Here are photos and reports from East Zone at Jamshedpur, North Zone at Delhi, and West Zone at Ahmedabad.

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.

Presentations in Pennsylvania and Park Grass: nutrient use and nutrient requirements for turfgrass

View across Park Grass in May 2006; the botanical composition is changed by the fertilizers and lime applied to the plots

In my presentations this week (handout here) at the Eastern Pennsylvania Turf Conference and Trade Show, I introduced the nutrient use and nutrient requirement talks by discussing the Park Grass experiment at Rothamsted. Do you know about this experiment? It is the longest-running ecological experiment in the world, with a start date of 1856. And it is on permanent grassland, with many species used as turfgrass growing there.

Soil samples collected from the Park Grass experiment in 1876 are stored in the Rothamsted archives

What does this ecological experiment have to do with nutrient requirements for turfgrass? Well, the results of the Park Grass experiment show that many species used as turfgrass can grow well at lower nutrient levels than one might expect, and certainly at lower levels of soil nutrients such as potassium and calcium than weedy species such as dandelion

The minimum levels for sustainable nutrition (MLSN) guidelines can be used to ensure that turfgrass plants are supplied with the necessary amount of nutrients, while avoiding overapplication of any nutrient. This article in the January 2014 issue of Golf Course Management explains how the MLSN guidelines were developed and how they can be applied.

In the presentations, I showed how a temperature-based growth potential can be used to estimate how much the grass will grow and consequently how much of each element will be used.


Based on growth potential calculated from average temperatures at Philadelphia, I estimated how much of primary and secondary plant nutrients would be used by the grass each month. Then, adding those values together, one can get an annual estimate of nutrient use.


I showed how waterfall charts can be used to look at an annual mass balance on an element-by-element basis, incorporating the amount in the soil and the MLSN guideline to ensure the grass will always be supplied with enough of each element.


For links to more information on these topics, please check out this handout which has a full explanation of these estimates and charts.

After the conference, I studied the 2013 weather data for Philadelphia and calculated the daily growth potential based on temperatures in 2013. Each point on this chart is the growth potential for cool-season grass for that day of the year, in Philadelphia, and the black line through the chart is the 15 day running average of growth potential through the year.


From these data I estimated the nitrogen use again and compared to what I discussed at the conference. Based on climatological normals data, I estimated 3.1 pounds of N/1000 ft2/year if the maximum monthly N were 0.6 pounds/1000 ft2, and 5.2 pounds of N/1000 ft2/year if the maximum monthly N were 1 pound/1000 ft2.

Using the 2013 data and daily growth potential, I made the calculations and got estimates of 3 pounds and 5 pounds of N, respectively.  

It was a great pleasure to see so many old friends and meet new ones at the conference. I would like to thank the conference organizers, especially Mike Fidanza from Penn State University, for inviting me and allowing me to talk about these exciting new (and historical) topics. I had a great time and I am looking forward to more discussion about these topics in the future.

Just what the grass requires: new article about nutrient requirements

Mlsn_gcmThe January 2014 issue of Golf Course Management contains this article I co-wrote with Larry Stowell and Wendy Gelernter from PACE Turf. Click here to read the article in GCM's digital edition.

Grass can only use so much of each element. That maximum amount the grass can use is a function of two things: how much the grass grows and the concentration of the element within the grass plant. From those basic principles, we can determine the minimum amount of an element that must be supplied to the plant. That is, the minimum amount to supply must be enough to meet the grass requirements. Applying more of an element than the grass can use will probably not produce any turf response.

The minimum levels for sustainable nutrition (MLSN) guidelines, as explained in the article, ensure that the nutrients supplied from the soil and by fertilizer applications are enough to meet the grass requirements. And by making some simple calculations to estimate grass use of each element, while accounting for the quantity of available nutrients in the soil, the MLSN guidelines reduce the risk of excessive nutrient applications.

See more at the MLSN page on Facebook and join superintendents around the world in the refinement of these guidelines through the Global Soil Survey.