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December 2012

The Ten Most Popular Posts of 2012

After 90 posts on the Viridescent blog, here are the ten most popular posts of the year, as measured by pageviews. Topics included turfgrass selection, climate charts, turfgrass videos, conference reports, turfgrass mysteries, and various other topics – but the most views were concentrated in one topic: turfgrass nutrient requirements and fertilizer. Seven of the top ten posts were in this category.

10. Turfgrass Nitrogen Requirement and Growth Potential
9. Turfgrass Mystery: how was this bunker revetted?
8. Turfgrass Mystery: can you identify the grass on this putting green?
7. How to Save 60% or More in Turfgrass Fertilizer Cost
6. Calcium for Turfgrass: is there enough in the soil?
5. Calcium deficiency in turfgrass, an imaginary problem?
4. Putting Green Fertilizer: getting it right
3. The Real Price of Fertilizer
2. Chemical Fertilizer Programs for Sand Based Rootzones - the 1 minute version
1. Five Articles Every Greenkeeper Should Read

Turfgrass Reports from Spain

In my two week trip to Spain, I visited the Canary Islands to see warm-season grasses, Madrid to speak at the Spanish Greenkeepers Congress, and Barcelona and Girona to see the grasses of Catalonia. I've written various updates about the interesting things I saw related to turfgrass management. Here is a list of these posts:

Golf Courses and Turfgrass on the "Miniature Continent" of Gran Canaria

Turfgrass at Gran Canaria: high season traffic, growth potential, salinity, and radio interview

A Report from Madrid: the 34th Spanish Greenkeepers Congress

Turfgrass in Catalonia: 1

Turfgrass in Catalonia: 2

Turfgrass in Catalonia: 3

Turfgrass Mystery: how was this bunker revetted?

Turfgrass in Catalonia: 3

Costa_bravaAfter seeing so many grasses at the PGA Catalunya Resort, and then even more at Barcelona, I must say I was surprised again to continue seeing such a variety of grasses as David Bataller and I went botanizing at the Costa Brava and the Semillas Fitó turfgrass experimental station.

In addition to the ten turfgrass species I already listed from the Resort, a look at the grass around the revetted bunker reveals an eleventh - fine fescue


To those eleven species, I can add Stenotaphrum secundatum (above)which we saw thriving as a lawn grass in some parts of Catalonia, and also Zoysia matrella, which we saw on a few traffic circles.


At the Semillas Fitó turfgrass experimental station we saw seeded kikuyugrass and seeded Cynodon dactylon along with a variety of cool-season turfgrass varieties. I was especially interested in the Playa seed mixture which looked great on the research plots and contains seed from four different species: Cynodon dactylon, Festuca arundinacea, Poa pratensis, and Lolium perenne


And at Golf Platja de Pals, the first course on the Costa Brava, designed by Fred Hawtree, and site of the 1972 Spanish Open, the turf is almost all Poa annua, and one can even find pink snow mold (Michrodochium nivale) in the shaded areas there.


I think it is pretty amazing to see thirteen turfgrass species, all performing pretty well, and even in early December to see green Stenotaphrum secundatum and green Zoysia matrella and green Cynodon dactylon alongside Poa trivialis and Poa annua. If I had a lawn in Catalonia, I think I would plant the Playa mixture from Semillas Fitó myself, just for the novelty of having a mixture of warm- and cool-season grasses in the same lawn, and because the other types of Festuca arundinacea that I saw were performing very well. 

In Southeast Asia, there are just a few species of grass that work well as a lawn or as a sports turf. In northern Europe, there are just a few species that work. At Catalonia, I saw thirteen species, all growing, to some extent, very well. In Sydney, or in Brisbane, or in San Diego, or in Atlanta, we can have a wide range of species, but I don't think I've ever been anywhere where such a wide range of grasses were growing.

Turfgrass Mystery: how was this bunker revetted?

Revetted bunkers are usually constructed with stacked pieces of sod. When I visited David Bataller at the PGA Catalunya Resort, he showed me this revetted bunker. He built it using natural materials, but he didn't use turfgrass sod. The question was, just what material is this?

The correct answer is cork, given first by Dr. Brett Morris,

and then by Dave Wilber:

Here is a closer look at this bunker.



And here is a cork tree on the course at the PGA Catalunya Resort.


Turfgrass in Catalonia: 2


After studying the grasses and growing conditions at PGA Catalunya, we went to Barcelona to study the grasses there.

SagradaAt the Sagrada Família, we found perennial ryegrass growing on a shaded lawn in front of this impressive building.

Then it was off to the largest stadium in Europe, Camp Nou, home of FC Barcelona. The turf here is primarily a blend of Poa pratensis varieties, and overseeding is done with Lolium perenne.

As at many stadia, especially in Europe, supplemental lighting is used to improve the turf conditions. Shade from the stadium structure itself, combined with the low global irradiance in the winter months, leaves the turf relatively weak. Supplemental lighting, such as this system from Stadium Grow Lighting (SGL), can produce a substantial improvement in turfgrass conditions.


Just how much extra light is provided by such a system? By my calculations, this lighting system will provide, over 24 hours of continuous operation, about 14 moles of photosynthetically active radiation (PAR) per square meter. Is this a lot of light, or is it a little? 

It depends on the context. During the summer months, or at any time of year in the tropics, 14 moles per square meter is roughly equivalent to 2 hours of unobstructed sunshine at midday. But 14 moles is also about the same as a full day of average sunshine at Barcelona during the month of December. And 14 moles is more than 4 times the light turf would normally receive at Edinburgh on a December day. 

Compared to the amount of light warm-season turf requires (and typically receives) either in the summer or near the equator, the amount of light provided by such a system is negligible. Running the lighting system for 48 consecutive hours would be the same as about 4 hours of midday sun. But for cool-season turf in the winter, running the lights for one day could be equivalent to almost a week of natural light. That is pretty substantial!


Barcelona is full of interesting places without any grass, and for the rest of the day I saw many of them. But I couldn't help but notice that even under the tram, one finds a fine turf between the rails. At first glance I thought it was artificial turf. Upon closer inspection, I saw that it was grass, with the leaves angled in the direction of the passing tram.


Turfgrass in Catalonia: 1

Occasionally I get to travel to places that have a tremendous variety of grasses. One of these is Hawaii – a wonderland of grasses. But at Hawaii it is a panoply of warm-season grasses. Recently I visited Catalonia, at the invitation of David Bataller, Golf Courses and Grounds Manager of the PGA Catalunya Resort. What I saw was really amazing! Almost every warm-season and cool-season turfgrass was growing in this region.

It is always interesting and a great learning experience to see so many types of grass. One thing that remains consistent about places where a lot of grasses, both cool- and warm-season species can grow, is this: these are among the most difficult places in the world to produce good year-round playing surfaces.


At this 36-hole facility, David manages primarily cool-season grasses, but there are also warm-season grasses – in fact, I counted ten different species of turfgrass, in total, being used on the property, plus lovegrass (Eragrostis) put to good use in many landscaping and out-of-play areas. In no particular order, they are:

  • Lolium perenne (C3)
  • Zoysia japonica (C4)
  • Pennisetum clandestinum (C4)
  • Poa annua (C3)
  • Poa trivialis (C3)
  • Poa pratensis (C3)
  • Agrostis stolonifera (C3)
  • Cynodon dactylon (and Cynodon hybrids) (C4)
  • Paspalum vaginatum (C4)
  • Festuca arundinacea (C3)

Why are there such a wide variety of grasses used for turf in Catalonia? If we look at a chart of growth potential through the year (Figure 1), it would seem that cool-season grasses would be a clear choice for this area. 

temperature-based turfgrass growth potential at Girona/Costa Brava, Spain

Figure 1. Temperature-based growth potential of C3 and C4 grasses based on climatological normals data for Girona, Spain.

The chart shows that the cool-season growth potential is higher than warm-season growth potential throughout the year. But what we find growing are both cool- and warm-season grasses. This is similar to a place like San Diego, California, where we can find seashore paspalum and bermudagrass and kikuyugrass growing alongside perennial ryegrass, Poa annua, and creeping bentgrass. 

The reason warm-season grasses perform well in this type of climate is because of water. Warm-season grasses have better water use efficiency than do cool-season grasses, and warm-season grasses generally have better salinity tolerance than do cool-season grasses. So in a climate where the evapotranspiration is higher than the precipitation, and where the irrigation water has some salt in it, warm-season grasses will compete well with and may even outperform cool-season grasses.


During the winter season, the warm-season grasses go dormant, as we can see with the Zoysia japonica on the bunker slope, but it is not cold enough for there to be any winterkill. 

PaspalumThere was even a local type of seashore paspalum (seedhead at right) that grows well in this area, and in fact some of the older golf courses near the sea in Catalonia have this native grass.

After the vist to PGA Catalunya Resort, my head was spinning. We had seen so many types of grasses, seen sunrises over the frost-covered courses, had discussed the soil and water salinity challenges, and tried to predict how certain grasses would grow at different times of the year. Maintaining fine turfgrass in a transitional climate, especially one without much precipitation, is really a challenge. 


A Report from Madrid: the 34th Spanish Greenkeepers Congress

I was recently in Spain at the invitation of the Asociación Española de Greenkeepers (AEdG) to speak at their 34th Congreso in Madrid. My presentations were about nutrient requirements for putting greens and about turfgrass management in Asia. 

Most of the greens in Spain are creeping bentgrass (Agrostis stolonifera), and I spoke with the delegates about the growth potential of that grass in response to different temperatures and how we can estimate how much of each element will be required by the grass based on growth potential and soil nutrient analyses. We can actually simplify the nutrient requirements of putting green turf to what is essentially a one-minute version – keep pH more than 5.5 and less than 8.3, apply enough nitrogen to produce the desired growth rate, and make sure soil potassium is more than 35 ppm and soil phosphorus is more than 18 ppm using the MLSN guidelines.


Jamon-iberico-vino-tino-AEdG-2012The exposition held in conjunction with the educational conference was crowded each time I visited, with approximately 300 people there to share information and learn more about turfgrass management. I really enjoyed visiting the booths, many of which were stocked with jamón ibérico and vino tinto

Other speakers at the Congress included Dr. Ron Duncan, Dr. Joe Vargas, and Dr. Alfredo Martinez. Dr. Duncan's presentation about irrigation water quality was a comprehensive overview of a major issue for turfgrass in Spain. I visited golf courses at Gran Canaria before the Congreso and at Catalonia after it, and in both of those places, and in speaking with turfgrass managers from other parts of the country, it became evident to me that managing the salts that are applied through irrigation is an absolutely essential aspect of turf management in Spain.

Dr. Martinez shared information on new research about diseases old and new to give the Spanish greenkeepers advice on the best way to control fungal diseases in the upcoming year.

The Congress was capped off with a gala dinner at the Casino de Madrid. At this fine dinner, lasting into the early morning hours of the next day, delegates and speakers enjoyed wonderful food, entertainment, and speeches in a rather grand setting. At this Congress, I made new friends and spent time with old ones, learned a lot from the delegates and from the other speakers, and had a great time, as I'm certain the other delegates did as well.


Registration Now Open for Sustainable Turfgrass Management in Asia 2013


Registration is now open for Sustainable Turfgrass Management in Asia 2013. This three day conference attracts more than 200 delegates from about 20 countries.

Woods_field_dayHeld at Pattaya's Amari Orchid Hotel, this year's program features classroom education on topics related to practical turfgrass management – irrigation, fertilizer, equipment, maintenance costs, new techniques for managing turf – and the Asian Turfgrass Field Day at Siam Country Club. Speakers include John Neylan from Australia and Les Jeremiah, CGCS from Hawaii, Kittipong Haranrat from the TGCSA, Dominic Wall from The R&A, and Dr. Micah Woods from the Asian Turfgrass Center. 

Download the registration form here.

Make your hotel booking directly with one of the conference hotels here.

This conference is organized for the Thailand Golf Association by the Thai Golf Course Superintendents Association and the Asian Turfgrass Center, with the support of The R&A. If you've attended the conference in past years, you know what a fun and informative event it is, providing useful information for your work, great networking opportunities, and a chance to learn from your peers and international speakers. If you've not attended in the past, we hope you will be able to attend the 2013 event to see for yourself.


A Fertilizer Miscellany: cost, phosphite, and nutritionism

Fertilizer cost

Roots_cynodon_urea_kclIn a series of posts listed below, I've written about the most affordable nutrient sources that can be used to fertilize greens and get excellent results. The important thing is supplying the right amount of the necessary elements. The bermudagrass putting green at right was fertilized exclusively with urea and potassium chloride to supply just the right amount of N and K, and the good result is evident.

The implication is this: every turfgrass manager should be aware of what the minimum cost is, and any difference in cost between the minimum and the actual cost of fertilizer should be justified.

Then, in this post on Facebook by a fertilizer distributor, it was mentioned that “Let’s hope the financial controllers at each club don’t read it.” Actually, I think everyone involved in the management of clubs, greenkeepers, general managers, and yes, even financial controllers, should have some idea of how much the costs are. I don’t expect that any financial controllers would read this, but why greenkeepers would need to hide anything about how much money they spend on fertilizer is beyond me.

Let’s look at estimated nutrient costs in a few more cities, making the same assumptions as before: 18 holes of greens occupy one hectare, we will use the temperature-based growth potential developed by PACE Turf to estimate nitrogen requirement (shown in Figure 1 below), and we will use a maximum of 4 g N/m2/month for bermudagrass greens and 3.5 g N/m2/month for cool-season greens when growth potential is at an optimum. Let's consider estimated nitrogen requirements for bermudagrass greens at Mumbai, bentgrass greens at Madrid, and bent/Poa greens at London, England and Portland, Oregon.


Figure 1. Estimated nitrogen requirement through the year for bermudagrass greens at Mumbai and bentgrass greens in London, Madrid, and Portland, based on the temperature-based growth potential of PACE Turf.

This model predicts an annual N requirement at London, Mumbai, Madrid, and Portland of 12, 43, 19, and 18 g N/m2/year, respectively. We are using the MLSN guidelines combined with a temperature-based growth potential to estimate nutrient requirements, and for each of these soils let’s assume we have the fairly typical situation for a sand rootzone of pH at 6, P at 40 ppm, and K at 50 ppm. In this case, we will apply N based on the estimates shown in Figure 1, no P is required, and we will apply K at half the N rate to meet the full grass requirement. Using urea and potassium sulfate to supply these nutrients, how much does it cost? 

Figure 2 shows the accumulated fertilizer cost for each city through the year, using local fertilizer prices from the fourth quarter of 2012 at current exchange rates, with all prices expressed in USD for convenience.


Figure 2. A step chart showing the cost for nitrogen and potassium to fertilize 18 greens for one year with urea as the N source and potassium sulfate as the K source.

Portland is the most expensive, with an annual cost of about $700. Mumbai, although it is the location using the most fertilizer, has the cheapest cost, at less than $500 per year, because of government subsidies for these fertilizers. These prices are similar to those estimated previously for Thailand, Vietnam, Japan, and Canada.

These are the baseline costs, then one can spend more, but one should be able to justify the added expense in fertilizer by whatever improvement one can get over the results one gets with urea and potassium sulfate. 

Phosphite is not a fertilizer 

I'm sometimes asked if phosphite is a fertilizer or a source of P to grass. Some people claim that phosphite is a nutrient. In plain terms, we can say that phosphite is not a fertilizer.

Phosphite does not provide plant P nutrition and thus cannot complement or substitute phosphate at any rate. 

Phosphite does not have any beneficial effect on the growth of healthy plants. 

Indirectly providing P by phosphite to phosphate oxidation is not an effective means of supplying P to plants compared with phosphate fertilizer.

These quotes are all from Soil Science and Plant Nutrition in an article by Thao and Yamakawa entitled Phosphite (phosphorous acid): Fungicide, fertilizer, or bio-stimulator

To prevent pythium, yes, phosphite is an effective fungicide. But as a fertilizer? It is not effective at all. And as a broad spectrum fungicide? It's not that either.


Foy-nutritionism-10-19-12John Foy, director of the USGA Green Section’s Florida Region, recently wrote an article about nutritionism. When such a knowledgable and well-respected figure writes about this topic, we have a great chance to learn from his sage advice. 

For me, there are three key points in the article. First, Foy explains nutritionism and then cautions against “focusing on individual nutrients far and beyond what is practical or necessary.” 

Second, he discusses products that go beyond supplying the basic macro- and micronutrients and that are reported to enhance turf health, noting “there is still not enough unbiased research to support most of the claims being made. Also, there are questions about whether or not the increased costs are justified.”

Third, he concludes by stating that a reliance on nutritionism “is not the answer or even a proven approach in sustainable turfgrass and golf course management.”

This is excellent advice. The fact is, turfgrasses are deliberately and rightly maintained to be deficient in nitrogen. If all the nitrogen the grass could use was applied, the grass would grow much too fast. For this reason, it is almost unheard of to have a deficiency of any other element, and that is why the MLSN guidelines are so effective, why applying the right amount of nitrogen is so important in producing good turfgrass conditions, and why we can create such fine turfgrass surfaces, as pictured here, by using the very basic nutrient sources.

T-1 creeping bentgrass in Japan

Turfgrass at Gran Canaria: high season traffic, growth potential, salinity, and radio interview

Rcglp_sun_dayDuring my visit to Gran Canaria, I visited all seven golf facilities on the island. It is interesting to consider how the different grasses are performing. Although Gran Canaria has an exceptionally salubrious climate for people, it actually can be a difficult place to manage turfgrass.

The main turfgrasses being grown on the golf courses are:

  • kikuyugrass (Pennisetum clandestinum)
  • seashore paspalum (Paspalum vaginatum)
  • bermudagrass (Cynodon spp.)
  • creeping bentgrass (Agrostis stolonifera)

The first three of these are warm-season grasses, meaning they grow most rapidly with an average temperature of more than 27°C. Creeping bentgrass is a cool-season grass, and it grows best at a temperature of around 20°C.

There are three interesting things that we can note related to the grasses and the temperature here. 

1. When we plot the temperature-based growth potential of cool-season and warm-season grasses based on climatological normals weather data at Las Palmas, we see that the growth potential for cool-season grass is higher than that for warm-season grass for each month of the year. For more about growth potential, see this article by Dr. Wendy Gelernter and Dr. Larry Stowell of PACE Turf.

temperature-based turfgrass growth potential at Las Palmas de Gran Canaria, Spain

Figure 1. The temperature-based growth potential for C3 and C4 grasses based on climatological normal temperatures from Las Palmas de Gran Canaria. 

2. The grasses on the golf courses of Gran Canaria are almost all warm-season, but the growth potential model predicts that the temperatures are ideal for cool-season grasses. Why is it that we find the warm-season grasses predominating?

It is because of water. The eastern and southern parts of the island, where the golf courses are located, receive very little precipitation. Supplemental irrigation is required to keep functional golfing surfaces, and that irrigation is both limited in supply and rather high in salinity. Some irrigation supplies on the island have an electrical conductivity of almost 4 dS/m. 

Warm-season grasses such as bermudagrass and seashore paspalum have lower water use rates than do cool-season grasses, and these warm-season grasses are also more tolerant of salinity. This allows the golf course turf to be maintained with a minimum of water. This benefit is enhanced by the rather cool temperatures during the winter months, and in fact, for seven months of the year at Gran Canaria, the warm-season grasses grow at less than 50% of their potential, which means they use less water. The relatively low growth potential for warm-season grasses mean they will use less fertilizer also.

3. The resort courses at the southern part of the island see high traffic during the months of October to April. This creates a challenge for greenkeepers because the very season at which traffic is highest is also the season at which the primary turf of bermudagrass or seashore paspalum has its slowest growth. 


Micah Woods, Alejandro Nagy, and Fernando Suarez on a seashore paspalum tee at Maspalomas Golf


As I spoke with greenkeepers around the island, and as I mentioned in my radio interview with Chicho Morales on Bajo Par Canarias, the most important thing in managing good turf on Gran Canaria is water. Applying the right amount of water to the turf, and managing the salts that are applied in the irrigation water, by leaching, will lead to the best possible turfgrass conditions. 

Listen to the radio show here, with extended comments from me starting at about the 10:00 mark, some good questions from host Chicho Morales, and translation and additional remarks on my visit by Alejandro Nagy and Daniel Carretero.

For more information, I wrote about the golf courses and grasses of Gran Canaria in this post, and you can see photos of the different grasses and golf courses at Gran Canaria here.