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March 2014
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May 2014

April 2014

In which I wrote a long answer to a short question about golf course grass in Rio de Janeiro

I've written this answer to a question I received last month about grasses for the Olympic Course in Rio de Janeiro.

The GEO Sustainable Golf Development Guidelines give a simple criterion for grass selection:

Sustainable grassing plans are based on the use of the most drought-tolerant and disease-resistant turfgrasses for the locality.

Read the question and my answer to learn more about expected performance of manilagrass and seashore paspalum.

Water in the Soil: new article in GCM China


My (turfgrass talk) column in the March/April issue of GCM China discusses water in the soil. I wrote about the amount of water that is held in the soil and how the amount of water expressed as a percentage can be converted to a volume of water. 

The article can be downloaded in Chinese or in English.

Topics for previous articles in this series include:

Coming up in the next issue, I'll be writing about nitrogen use and nitrogen application rate.

Turfgrass Growth Potential: 4 cities, 472 days

The temperature-based turfgrass growth potential predicts how grass growth can respond to temperature. This growth potential (GP) was developed by PACE Turf and has been put to many uses such as predicting the time of overseeding, estimating turfgrass nitrogen requirements, assessing turfgrass stress, and evaluating growth and optimum times for various maintenance practices.

When the temperatures are not conducive to growth for cool-season (C3) or warm-season (C4) grasses, there isn't much one can do to force the growth. Extra nitrogen can be added, but it really doesn't have its full effect until the temperatures get into an optimum range for growth.

After reading that tweet, I looked up the temperature data for Tulsa. Sure enough, the growth potential for C3 grass has been pretty low for the past month. Growth potential of C3 and C4 grasses at Tulsa are plotted in this chart, with data included for the past 472 days, from 1 January 2013 until 17 April 2014.

I find the growth potential useful in a lot of ways. On golf courses with both cool and warm season grass, as at Bristol Hill Golf Club near Kisarazu, it can be useful to study the growth potential when planning maintenance activities.

Cool season (C3) and warm season (C4) grass at Bristol Hill Golf Club near Kisarazu, Japan

The GP at Kisarazu for the past 472 days is show below. Ideally, disruptive maintenance practices such as scarifying or core aerification will be done at times when the turf has a high growth potential. This allows for a rapid recovery time and minimizes disruption to play.

I looked up the data for a couple other cites. At Sydney (data from the Sydney Airport), the temperatures are milder.

At Dubai, the temperatures are more extreme.

 With all the variation in temperature from place to place, there is also a big difference in the way grass will respond. The growth potential puts a numerical value to this. This can then be used in maintenance planning, in useful comparisons to other locations, or in explanations of why the turf is responding in a certain way.

Monthly Turfgrass Roundup (March 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:

In thousands of paired measurements of soil moisture and surface hardness, these are the general trends.

278 delegates from 20 countries attended the Sustainable Turfgrass Management in Asia 2014 conference. Photo galleries from the conference here, here, and here.

Handouts and presentations from the Sustainable Turfgrass Management in Asia 2014 conference

Golf course architect mystery

The two-green system in Japan

A different type of fan for putting greens

MLSN in Spain

Tee divots and manilagrass

Photos from the India Golf Expo 2014

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.

Fertilizer requirement identified with 3 numbers

Last week at the Vancouver Island Golf Superintendent Association meeting, I spoke about turfgrass nutrient requirements. The question a turfgrass manager must answer is this one: Can the soil supply enough of an element to meet the grass requirements, and if it cannot, then how much of the element must be applied as fertilizer?

The presentation handout and slides contain the detailed answer to that question. The short answer is that we can identify the amount necessary as fertilizer from just 3 numbers:

  1. the amount we have (soil test amount)
  2. the amount we need to have in the soil (the MLSN guideline)
  3. the amount the grass will use

To find how much of each element is required as fertilizer, we look at the total amount that must be present, which is the amount the grass will use (3) added to the amount we need (2) in the soil.

Then we compare that amount required (2 + 3) to the actual amount we have (1). If the amount we have is more than the amount required, that element is not needed as fertilizer. If the amount we have is less than the amount required, that difference is the amount needed as fertilizer. The handout has a full explanation of how to get these numbers.

Potassium + Dogma Might Increase Turf Problems

Last week I read two contrasting things about potassium and Microdochium nivale (fusarium patch or pink snow mold).

In the March Greenkeeper Internationalthis article about fusarium patch instructs one to:

Feed turf by all means - but with fertiliser formulations rich in potassium to make the most of the ‘gatekeeper’ nutrient with its intrinsic abilities in good water relations and strengthening of grass plant tissues.

There was also this, from Doug Soldat, showing an interesting result in which M. nivale was increased by potassium application:

When it comes to potassium application, one should not think that adding potassium will always "strengthen" the plant or improve resistance to diseases. Eliminating a potassium deficiency is almost always a good thing. Eliminating the deficiency will improve root growth, increase leaf growth, and ensure that the grass is able to function normally. Adding potassium beyond the amount required to eliminate the deficiency may cause problems.

  • dandelion increased by potassium application
  • snow mold increased by potassium application
  • foliar disease of bermudagrass increased by potassium application

Because too little potassium is problematic, and too much can also cause a problem, the approach to potassium fertilizer that seems most likely to optimize turf performance is this one - supply the potassium the grass requires, but only that amount.