Previous month:
November 2013
Next month:
January 2014

December 2013

Counting Down, Top 5 posts this year

Here are the 5 most viewed posts from this year. In 2012, the most viewed posts were about fertilizer. This year, fertilizer was a popular topic, but so were irrigation and turfgrass mysteries.

  1. Summertime syringing to cool bentgrass greens: I wouldn't do it today
  2. Turfgrass Mystery: what happened to this green?
  3. Turfgrass Nutrient Requirements and Fertilizer Choice
  4. For irrigation, which is better? Deep and infrequent, or light and frequent?
  5. How Much Potassium Does Grass Require?

I previously listed the 5 top posts from 2009, the top 5 from 2010, the top 5 from 2011, the top 5 from 2012, and #6 to #10 from 2013.

Turfgrass, Overseeding, and Growth Potential at Dubai

The 8th hole on the Majilis Course at Emirates Golf Club

Last week I had the chance to visit Emirates Golf Club and Dubai Creek Golf and Yacht Club. I saw some beautiful grass, and I was interested to learn about the overseeding that had just been completed. Most courses at Dubai are bermudagrass, although some have been planted to seashore paspalum. The seashore paspalum courses don't seem to be overseeded, but the bermudagrass courses often are.

Tifeagle greens on the Majilis Course are not overseeded; all other turfed areas are overseeded

The Majilis Course at Emirates Golf Club hosted the Omega Dubai Ladies Masters from 4 to 7 December, and will host the Omega Dubai Desert Classic from 30 January to 2 February. There is therefore a tight window when overseeding can be done, and I was interested to see how this practical timing of overseeding (fairways and greens surrounds were seeded on 8 to 10 December, rough was seeded on 4 to 6 November) was related to the growth potential of the existing bermudagrass and the cool-season perennial ryegrass. 

I've written a lot about a temperature-based growth potential, especially about how it is related to estimating fertilizer requirements, but the growth potential was originally developed by PACE Turf to look at timing of overseeding. I've written about this as it relates to overseeding of football grounds in Japan, and I have looked up the temperature data for November and December 2013 at Dubai, to see how the growth potential was for C3 and C4 grasses.

Growth potential for cool-season grass (Dark Green) and warm-season grass (Red) based on November and December 2013 temperatures at Dubai

It looks like the temperatures fortunately coincided with the overseeding time window this year. The overseed was done 8 to 10 December, and at that time, the warm-season growth potential was just above 0.5, and within a week it would move below 0.5. At the same time, the temperatures were such that from 10 December onwards, the cool-season growth potential was at 0.75 and increasing. In the rough, where the overseeding was done in early November, there was still a lot of bermudagrass in some areas, due to the strong growth of bermuda throughout November; growth potential of cool-season grass did not exceed that of warm-season grass until the 3rd week of November, and temperatures remained warm enough for bermudagrass to grow well until the end of December.

At Dubai Creek, the tees and rough were overseeded on December 9, and with that timing, the perennial ryegrass has established very well. Fairways at Dubai Creek are not overseeded but the bermudagrass retains an excellent color although the growth rate slows in the cool weather.

The 18th at Dubai Creek Golf and Yacht Club; bermudagrass fairways are not overseeded, but perennial ryegrass has been overseeded into the rough

More about turfgrass at Mauritius

Seashore dropseed growing on the beach near Bel Ombre, Mauritius

I visited Mauritius this month for a seminar (report and presentation slides here) and a bit of a botanizing holiday. Mauritius is a fascinating place to study grass. It is one of the Mascarene Islands. If that name sounds familiar, it should -- one of the common names for Zoysia tenuifolia is mascarenegrass. 

One finds a wide range of grasses growing in the wild and as managed turf at Mauritius. I've written about some of the grasses I saw when I visited for the first time a few years ago.

Mascarenegrass produces a dense turf in a highly trafficked park at Gris Gris, Mauritius

The golf courses at Mauritius (there are 8) use bermudagrass (Cynodon), primarily, although 2 of the courses have seashore paspalum (Paspalum vaginatum) everywhere, and 1 more course has seashore paspalum on the greens.

Bermudagrass grows well beside the sea on the 17th hole at Anahita, Mauritius

 One can find seashore paspalum growing in low-lying wet areas at Mauritius. Seashore paspalum is not tolerant of drought, so one does not find it in the wild in areas that do not have a regular supply of water.


Paspalum (1)
Seashore paspalum growing at the edge of and into a pond at Belle Mare, Mauritius

The golf courses at Belle Mare are bermudagrass, with some Stenotaphrum secundatum growing in rough, in the shade, and in unmown areas.

The 17th hole on the Legends course at Belle Mare, Mauritius; Stenotaphrum is growing in the unmown foreground, with bermudagrass on the green and surrounds

The Paradis course is near sea level and has seashore paspalum greens and bermudagrass on tees, fairways, and rough.

Talking about different grasses and their management at Paradis Golf Club at Le Morne, Mauritius

There are interesting turf evaluation plots at Paradis. And even more interesting is to observe what grasses are growing, and how they perform, on the course. One can find different types of seashore paspalum on the greens, seashore dropseed growing right beside the lagoon, bermudagrass covering most of the course, Stenotaphrum secundatum in much of the rough, and even some patches of mascarenegrass.

The seashore paspalum performs well on the greens at Paradis, and on the fairways, it makes an excellent turf in the low areas that seem to be at or below sea level, where the bermudagrass does not persist. But on the drier areas of the course, which consists of most of the fairways and rough, on generally sandy soil, the bermudagrass and Stenotaphrum dominate the sward.

Turfgrass Mystery: identifying the underwater grass

This one, I think, will be relatively straightforward. Last week I was at Mauritius. I spoke at a seminar, and I also had a chance to explore the island and to study the grasses growing near the ocean.

Beach_grassI saw this grass growing at nearly every beach, on all sides of the island. It clearly has a high salt tolerance, because at high tide, the ocean water completely inundated some of the plants. I didn't notice salt causing any damage to the grass.

This grass was also observed slightly up from the water line, where the sand and grass were not inundated daily.

It was especially impressive to see this grass, at high tide, completely covered by ocean water.


The mystery I would like to solve is this one: what species is this grass?

The answer to this mystery is Sporobolus virginicus, correctly solved by Mark Field:

There are a number of interesting characteristics of this grass that set it apart from two other common grasses (Paspalum vaginatum and Zoysia matrella) found in tropical coastal areas.

  • S. virginicus is adapted to low rainfall and is very drought tolerant with low water requirements
  • S. virginicus is believed to be pest-free
  • Z. matrella is less widespread and one doesn't find it so much growing in sand; Z. matrella is found close to sea level and in saline conditions but usually is anchored onto rocks or other stable surfaces
  • P. vaginatum will not tolerate drought and prefers moist to saturated sites

This fact sheet from the USDA provides details on S. virginicus.

Dr. Brett Morris shared the above photo of S. virginicus growing in it's typical environment, right on the sand near the high tide line, where it will sometimes be inundated with saline water, and sometimes be exposed to extended periods of drought stress.

Sporobolus1The leaves of S. virginicus and P. vaginatum appear very similar, and the best way to tell these grasses apart is to find plants with spikelets. There are profound differences in spikelet morphology between the two species. 

At right is S. virginicus found on the beach at Bel Ombre, Mauritius. Note the spiciform (spikelike) panicle. P. vaginatum, however, has paired racemes, as shown below.

seedhead of salam paspalum vaginatum

Counting Down, Top 10 Posts of 2013 (#6 to #10)

Last year, the most viewed posts on this blog were all about fertilizer. This year, turfgrass nutrient topics were popular again, but a broader range of topics made it onto the list. Here are #6 to #10 on the 2013 list:

6. The Unambiguity of Turfgrass Nutrient Indicies 

7. Turfgrass Mystery on the Putting Green

8. Explaining the Turfgrass Growth Potential

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

10. An Exemplary Guide to Control of Turfgrass Diseases

I previously listed the 5 top posts from 2009, the top 5 from 2010, the top 5 from 2011, and the top 5 from 2012.

Coming up next week, I'll share the top 5 from 2013.

Report & Presentation Slides from Mauritius Seminar


Today's seminars at the Le Heritage Telfair Golf and Spa Resort in Bel Ombre drew 39 delegates, with representation from nearly all the golf clubs in Mauritius. The seminar was hosted by the resort and was put on by Bernhard & Co. with support from local companies S.C.E.T.I.A Ltée & COROI Maurice.

WoodsI spoke in the morning about Putting Green Nutrient Requirements. The presentation slides are available for download as a PDF file. I also shared this handout which contains links to many of the research papers and examples and template forms that I introduced in the presentation. 

My second presentation was on Measuring Turfgrass Performance (download slides here) in which I discussed the (sometimes) relationship between soil organic matter, soil moisture, and surface hardness. This led to a discussion of organic matter management and tine spacing. I then shared the results to date of stimpmeter measurements and Clegg Hammer measurements from hundreds of putting greens. Of particular interest to golf course superintendents in Mauritius would be the green speed of ultradwarf bermudagrass and seashore paspalum; in 75 measurements on ultradwarf greens, the median speed has been 9 feet 4 inches. In 123 stimpmeter measurements on paspalum greens, the median speed has been 8 feet 4 inches. 


Steve Wilson from Bernhard then gave a classroom seminar about quality of cut and reel and bedknife sharpening, following that up with a demonstration of reel grinding and bedknife grinding at the Heritage Golf Club workshop. 


Counting Down, Top 5 Posts of 2012

Various interesting posts hide in the back pages of blogs, and I've enjoyed seeing which of the posts from the early years of this blog were most popular, as measured by the number of pageviews.

Continuing with the lists of top posts by year since the inception of this blog in 2009, here are the 5 posts with the highest pageviews from 2012:

  1. Five Articles Every Greenkeeper Should Read
  2. Chemical Fertilizer Programs for Sand Based Rootzones - the 1 minute version
  3. The Real Price of Fertilizer
  4. Putting Green Fertilizer: getting it right
  5. Calcium deficiency in turfgrass, an imaginary problem?

I previously listed the 5 top posts from 2009, the top 5 from 2010, and the top 5 from 2011.

Coming up next week, I'll share some of the most viewed posts of 2013.

Turfgrass Mystery: the line on the green

This mystery comes from a putting green in Spain. The grass is Penn A-4 creeping bentgrass. One can see at the corner of the green a mark from the triplex mower as it makes the cleanup pass. And diagonally across the green, there is this line of damaged grass. Here is a closer look at the mysterious line.


Can you identify the cause of this line on the green?

Greg Austin was the first to identify this as an ant trail across the green:

Steve Agin also correctly identified the cause of this line. Getting closer to ground level on the green, one can see that this is an ant trail. Thanks to David Bataller for sending the photos for this turfgrass mystery.



This ant problem is similar to this turfgrass mystery that turned out to be termite damage on a bermudagrass (Cynodon) putting green. Click here to read all the previous turfgrass mysteries.

IGU East Zone Greenkeeper Education Programme at Jamshedpur


The Indian Golf Union held their East Zone greenkeeper education programme at Jamshedpur from 9 to 13 December. The delegates, who came from East India and from four golf clubs in Bangladesh, were hosted by the Beldih Club.


Classroom seminars focused on golf course grasses and how they grow, along with how we modify the growth rate and the grass to make a good playing surface for golf.

East2These classroom sessions were supplemented by on-course sessions where we looked at grass and soil conditions, observed the amount of organic matter, and measured the soil moisture, green speed, green reliability, and green firmness.

In a visit to the Golmuri Golf Course, we also identified hydrophobic conditions and discussed how to prevent and manage those. We also discussed weed management, fertilizer application techniques, and golf course construction methods.


One of the interesting measurements we looked at this week was The R&A's Holing Out Test. In this test, we measure the reliability of the putting green surface from a range of distances, with the ball set at just the right pace and line to go in the hole. Any miss, then, can be attributed to imperfections in the green surface. This gives us an indication of the reliability of the putting surface.

East5Throughout the week, we discussed the practical aspects of greenkeeping along with the technical ones. One of the main points discussed was how the growth rate of the grass can be modified by adjusting the amount of nitrogen and water that are applied to the grass.

By adjusting the growth rate, one can change the playing surface and one also can control the rate of organic matter accumulation. Many of the maintenance practices such as sand topdressing, verticutting, and core aerification are conducted in order to manage the organic matter. We disucssed how these practices can be adjusted at each golf course to produce good playing surfaces in this part of the world.