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February 2016

This is not a very good article, and I don't recommend it

Unfortunately, I wrote the article. I wouldn't usually draw attention to articles that I don't think are very good, but in this case I feel obligated to, after receiving an inquiry about it:

"Hi Micah, Do you recomend this as still actual or is it need to be updated?"

Attached to the e-mail was a copy of The "Best" Soil Test, an article from 2005 that I'd almost forgotten about.


Actually, I'm not sure how it came to be published in CUTT with that title, because it was originally published in TurfNet Monthly in May 2004 with the title Q&A: Water-based extraction methods for turf soils.

"Probably it will just need a little update," I thought. But when I sat down to read it, I realized I think so differently now that I don't want to recommend it, nor do I think it worth updating. What I could do, however, is clarify just what it is I disagree with in the article, and which I do think is "still actual."

First, I recommend the original TurfNet Monthly version. Formatted as a Q&A, it doesn't seem so haphazard. And the Qs I posed to myself were in direct response to what I was writing as a follow-up to, which was the Carrow et al. article that I mostly agreed with, and the Simmons article that I largely disagreed with.

Second, let me go through my article -- the TurfNet May 204 version -- noting the points I'd like to emphasize or correct today.

"Given these contrasting opinions on the utility of water-based extractions, it seems that some additional information about these tests may be helpful."

Umm, apparently it seemed like it might be helpful when I was a graduate student, but now it just seems like extending an argument. Better just to say that water-based extractions (of which saturated paste tests are one) shouldn't be used to assess the nutrient requirements of turf. And be done with it. But I wasn't.

"the results are useful but are often misinterpreted."

I don't know that I'd even call the results useful today. I used to think information was useful just for the purpose of knowing; now I think that information in the context of turgrass management is useful only when the information can be used as a decision making tool. Because the results of a water-based extraction cannot be used as a decision making tool in determining if an element should be supplied as fertilizer, I don't think the results are useful.

"if you want to use soil test results to develop a fertilizer program, use a different extraction method."

Still agree. It would have been a better article if I just wrote that sentence.

"Soluble ions are important because those are the ones that the roots can access."

Sure. But this is only "important" in the sense that it is important for research purposes. I had a different perspective in 2004 when I was in the middle of a research project about the comparison of different soil tests. For the determination of turfgrass nutrient requirements, it is not necessary or even helpful to know the quantity of soluble ions.

"To diagnose a phosphorus deficiency, I would collect a few tissue samples"

I don't think tissue testing should be a part of turfgrass management. I did then. Now I only do tissue testing for research. I think tissue testing is really useful for research, but not useful for determining if an element is required as fertilizer. Leaf nutrient analyses (tissue testing) provide lots of data, but can those data be used as a decision-making tool? Back then, I said yes. Now, I say no, no, no.

"Use the saturated paste test to assess nutrient relationships in the soil."

No, no, no, again! This is only useful for research. I can't understand how this would be useful in day-to-day turf management.

"I find it much more useful to look at soil test data as an indicator of available nutrients but to use tissue analysis as a means to detect nutrient deficiencies ... Tissue tests tell us what the plant has, so there are no questions about whether a certain nutrient is available or not, deficient or not, or sufficiently mobile or not. In the tissue there are either adequate amounts or there are not. Final answer."

Could I disagree with anything more than this? That is just wrong. The way I think today, that would be a really inefficient way to determine nutrient requirements and would introduce all kinds of error into the process.

I wrote that before Larry Stowell and Wendy Gelernter and I ever had the idea of MLSN or the Global Soil Survey. In 2004, I was really disillusioned with soil tests, because I thought they were difficult to interpret. I was still thinking that there were these ranges -- low, medium, high, etc -- that nutrient levels fell into. And trying to reconcile turfgrass fertilizer research results to those supposed levels provided lots of inconclusive results.

I did additional experiments in 2005 with sands that I had collected from around the world, finally starting to come up with the idea of minimum levels and not worrying about an element when it was above the minimum. But then, from 2006 onwards, I was interpreting soil tests making sure that P was at least 35 ppm, K above 50, and Mg above 75 ppm. And there were still all these great turf surfaces that were coming in with nutrient levels even lower than that. Then when Larry came up with the idea for the way we could analyze large datasets of soil test results, which we used to identify the MLSN guidelines, and then we followed that up with the Global Soil Survey as a way to check the guidelines even more broadly, those minimum levels came down. So now, if one interprets soil tests using the MLSN approach, all those problems that I was struggling with as a grad student in 2004, and my objections to soil tests then -- those problems go away. Because soil tests are easy to interpret, and the research makes sense, if one just makes sure that soil nutrient levels remain above the MLSN guideline.

As for tissue tests, I have the same problem with them now as I did with soil tests in 2004. I don't agree that what are considered adequate amounts are accurate enough for tissue tests to ever be used as a decision making tool. I've been studying this. And I spend lots of money on tissue tests. But I'm doing this for research purposes, and reiterate that I would not use leaf nutrient analyses for determining if an element should be applied as fertilizer.

"If one wishes to get the best commercially available approximation of soil solution, run a saturated paste test on your soil samples."

Haha. Can you tell I was a student when I wrote that? It seemed so interesting at the time to have information that could not be used for decision-making purposes. I don't see today how any turf manager would wish to get an approximation of soil solution. Again, this is something that is fascinating for research, but of no use in turf management.

"I am optimistic that it will soon be possible to interpret turfgrass soil tests with more clarity."

Eight years later, working with Larry Stowell and Wendy Gelernter from PACE Turf, we came up with MLSN. That solved the objections I was having to soil testing in 2004. And it makes what I wrote back then somewhat irrelevant.

"Which products and technologies are truly beneficial and cost-effective?"

This is an article I've recommended before, and share again here. It is Purchasing new products and technologies: an ethical and common-sense approach by Dr. Robert Carrow.


Dr. Carrow explains a procedure for golf course superintendents who want to stay on the cutting edge of advancements to make "wise decisions about purchasing new products/technologies." He explains the ethical aspect, the need for information, and the application of common sense.

Regarding ethics of purchasing, he writes:

Specific science-based information is often limited or lacking for many new products/technologies. Substituted for testing and evaluation may be manufacturer claims, testimonials, and psuedoscience (claiming a product can theoretically provide a response while knowing that the magnitude is very small, or providing "selected" data to support a claim while withholding data that proves otherwise).

Why is this an ethical issue? He explains it like this (italics his):

The ethical point is that golf club officials assume that the golf course superintendent is making science-based decisions on new products/technologies when spending their money ... Thus, expending large amounts of club funds for testing a new technology is an ethical issue when the decision is based on "I hope" rather than "I know" and the club bears the total cost if the technology fails to perform.

For information, Carrow gives seven questions that superintendents should ask themselves:

  1. Is this product needed in my situation?
  2. Are there better "alternatives"?
  3. Is the positive response due to the "active ingredient" or to an added material?
  4. How important is the response?
  5. Are valid, unbiased "test results" available?
  6. Should I try this item on a trial area or basis?
  7. Do the "benefits" justify the costs?

He gives lots of examples too -- read the article to see the types of products he mentions, like humic acid and humate products, acidifying soils or water, the addition of Fe and N to many products, microorganism addition, water treatment devices ...

He says the bottom line is whether the benefits to the golf facility justify the cost. Ask this question to yourself, he suggests, concerning the cost and benefit: "Would I purchase this product or technology with money from my personal bank account if I were the owner?"

Take ethics and information, add in a little common sense, and you'll be on the cutting edge.

Burning grass



Posted by 岡山後楽園 on Tuesday, February 2, 2016

Korakuen in Okayama is one the three great gardens of Japan, and I like it especially because of its expansive noshiba (Zoysia japonica) lawns. In early February every year, a shiba yaki (grass burning) ceremony is held at Korakuen, when the lawns are burned.

The video above shows the ignition of a lawn. The Facebook page of Korakuen has more photos of the shiba yaki ceremony this year.


Posted by 岡山後楽園 on Wednesday, February 3, 2016

It is pretty amazing how strange it looks before the lawns start to grow again.


Posted by 岡山後楽園 on Wednesday, February 3, 2016

For more about grass burning in Japan, see:

I misunderstood the question about pH

Allan Dewald asked about upward revision of the MLSN guidelines at high pH:

I misunderstood that question at first. I thought he meant that if one has good grass at pH 9, then would an upward revision of suggestions about pH be warranted? But as I started composing my answer and read again his question, I'm now taking it to mean that if one has a root zone with pH 9, is an upward revision of the minimum levels for elements such as K, Mg, P, and Ca necessary?

My answer, to both of those questions, is no. Here's why.

First, calcareous soil that doesn't have an alkalinity problem will have a maximum pH of about 8.3. When the pH is more than 8.5, then it is not calcium carbonate causing that -- there is sodium or some other source of alkalinity. A pH of 9 can be problematic, and one doesn't want to grow grass at that pH. Therefore, one will likely be doing things like acidifying irrigation water, or leaching, or applying elemental sulfur, and doing more leaching, in order to get the pH closer to 8.3. In that case, I don't think it matters what the soil nutrient levels are. There is no need for guidelines for those type of soils. My recommendation is to make treatments to deal with the alkalinity and just supply the grass with the amount of each element that it can use. Don't worry about soil nutrient levels.

Second, the current MLSN guidelines were developed from an analysis of soils with pH from 5.5 to 8.5. That's the pH range at which most good turf is found. It is probably more common to have good turf at less than 5.5 than it is to have good turf at pH above 8.5. In the Global Soil Survey through 31 August 2015, the samples have a pH from 4.6 to 8.2 with a median of 6.4.

pH of Global Soil Survey samples

Because our analyses of the MLSN data were restricted to soils with pH from 5.5 to 8.5, and because the data collected from the Global Soil Survey so far have a range from 4.6 to 8.2, we can make some suggestions about nutrient levels in soils within those pH ranges. But for pH 9, the data we have don't give us any information about what the nutrient levels should be for good performing turf at that pH.

That's why I would not worry so much about soil nutrient levels at extreme pH levels, and I would (especially if the pH was high) try to get it closer to 8.3, and I would not use the MLSN guidelines, but rather would just supply the grass with the amount of nutrients it uses. This is essentially the Precision Fertilisation method of STERF.

Soil potassium, from significantly unavailable to highly available

Yesterday I wrote about extractable vs. available elements and why that is not how to interpret soil tests. This is another example.

When I was a graduate student at Cornell, I did some research on the flagged section of L-93 creeping bentgrass in this photo.


I collected soil samples, did lots of different soil tests on those samples, applied different rates of potassium (K) to the plots, then did more soil tests and tissue nutrient analyses.

This green was a calcareous sand, the grass quality was not improved by any addition of K fertilizer, and soil samples were taken to a depth of 4 inches (10 cm).


At the start of the experiment, before making any K applications, samples were tested for K using different testing methods. The data in this chart are all the same soil, taken from the same section of the green on the same day, and the difference in the results is due to the testing procedure -- the extraction method.


The quantity of K extracted by the different methods ranged from 8 ppm in water to more than 10,000 ppm in a complete digestion of the soil. If you want to read about different forms of K in the soil, this is a good document. You'll notice that the terminology from the soil scientists is not the same as the terminology on the abc report I discussed yesterday.

Suffice it to say that different testing procedures applied to the same soil sample will extract different amounts of K from the soil. Here's a closer look at the more common tests, adjusting the scale and omitting the microwave acid digestion, which turns the sand into a liquid and measures the total amount of K in the soil.


I'm not suggesting one should test a single sample in multiple ways. What I do suggest is to pick a single method that works good for one's soil. The Mehlich 3 test is in common use and that is what we've used to develop the MLSN guidelines.

Then, the only thing one needs to do is compare the result of the test to the guideline. If there is enough, that element is not required as fertilizer. If there is not enough, that element should be applied as fertilizer. It is not a matter of availability. It is a matter of enough or not enough.

One could describe these same test results on some type of availability scale. I made this up. It sounds a bit ridiculous, kind of like this that I used as an inspiration. You can imagine that with a bit of thought, though, I could come up with availability descriptions that sound plausible. But that wouldn't make them correct, or meaningful, or applicable! It still comes down to enough or not enough.


It's not really about extractable or available

This seems to come up every few months, most recently in an e-mail inquiry. I paraphrase the words here, but keep the punctuation intact, and I omit course, company, and superintendent names:

I may have asked this before, but again it is soil test time and I got my results back. This year I used two different companies. Both samples were analysed by xyz labs but one also includes an abc report.

The numbers are quite similar in both but the abc report shows total ppm of an element plus available ppm of that element!

This is confusing me a little because you said if it is extractable it is also available?!?

I wrote back with this:

If you get your testing done by fertiliser companies you can expect this type of report. I think we have had this conversation before and I am not sure what else I can tell you.

I had a look at the reports that had been sent with the e-mail, and actually there is a little bit of what else. I can try to explain this in a different way. I can't share the reports, but you may have seen something like them.

In the regular report from xyz labs, the test results are provided in ppm. It is pretty straightforward. One page. Organic matter in %, pH, macronutrients in ppm, micronutrients in ppm. Basically numbers. Also cation exchange capacity (CEC), and calculated percentages of different ions making up the CEC.

The abc report is 3 pages. One page has numbers. It also includes organic matter in %, and pH, and macronutrient and micronutrients in ppm. Also CEC and percentage of ions. This page is mostly numbers. In fact, it is very similar to the regular report. The difference between the abc report and the regular report is that for most elements, there are now two values in ppm: total, and available.

On the other two pages of the abc report, there are lots of charts, some showing a comparison between total and available amounts and others plotting cation ratios. In the cation ratios section, it is shown that total is exchangeable, and available is extractable.

Charts of the total and available Mg and K, and of available ammonium, show them below the targets. The ratio charts come with a table, giving the interpretation that total Mg and K are optimal, but available Mg and K are high. Available ammonium is optimal.

My correspondent wrote, "this is confusing me a little."

I'd be confused too with the total and exchangeable and available and extractable terminology, and by the contradictory interpretations of high and/or optimal and then, for the same elements, the adjacent page shows them below the target.

The abc report recommends 12 specialty products based on these results, including products to address the low ammonium availability and the low total and available K that in other parts of the report are shown as optimal or high. There are also recommendations for inputs of 3 generic products. In total, 15 products recommended, with 12 of them from the company providing the abc report.

How can I respond to the correspondent who said "this is confusing me a little because you said if it is extractable it is also available?!?"

After all that, I don't think it is really about extractable or available. I'd suggest asking yourself, "what is the purpose of this confusing report?"

It really is not about total or extractable or exchangeable or available. A better way to think about this, and the words that I suggest are more appropriate are enough and not enough. For more, see:

December and January DLI in Everglades City, Florida

I've been reading about the rains and clouds in South Florida and how extraordinary the past couple months have been. I saw these charts from Travis Shaddox, and I wondered what the light would be in photosynthetic units.

I downloaded monthly summary data since March 2007 for Everglades City from the NOAA. I use these data because they include global solar radiation, and I converted from energy units of MJ/m2 to photosynthetic units of mol/m2 using the 2.04 conversion factor of Meek et al.

This shows the average daily light integral (DLI) each month. One can see the seasonal changes, and one can also see that December 2015 had the lowest DLI of any December and that January 2016 had the lowest DLI of any January. I plotted all the data I could get, which is since 2007; I don't know what the values would have been before that. In the past decade, though, these were the lowest.

image from farm2.staticflickr.comLooking just at December and January year by year, January 2016 really stands out for having a low DLI. Blue triangles are December DLIs and red circles are January DLIs; the vertical dashed lines (blue for December, red for January) show the averages prior to Dec 2015 and Jan 2016.

image from

In a normal year at Everglades City, January would have more photosynthetic light than December. For seven out of the past eight years, the month of December had a lower DLI than January.  Only 2014 had a lower DLI in January than in December. But January 2016 is a big outlier; not only does January 2016 have the lowest DLI of any of the previous Januaries, but it also has a lower DLI than any of the previous Decembers.

The R&A Seminar on Sustainable Golf Course Design, Renovation and Maintenance in Asia

There are a lot of seminars happening in Asia in early March. Two new events are available this year, one in China and another in Thailand. These are The R&A Seminar on Sustainable Golf Course Design, Renovation and Maintenance in Asia.

The first is on March 3 and 4 in Beijing:

The R&A is to host a free to attend seminar in China that promotes responsible and practical approaches to golf course design, renovation and maintenance - highlighting the ongoing work of the industry in raising the expectations for golf.  This seminar will provide the most comprehensive sustainable education event in Asia across golf developments, renovations and course management.

The R&A Seminar on Sustainable Golf Course Design, Renovation and Maintenance in Asia will be held in Beijing on 3 and 4 March, as part of the China Golf Show at the National Convention Centre.


The second is on March 10 in Thailand, focusing on "golf developments, renovations and course management."

The R&A Seminar on Sustainable Golf Course Design, Renovation and Maintenance in Asia will be held at the Amata Spring Country Club on 10 March.

Both seminars are free to attend.

More information and registration for the China seminar is here: registration closes on February 26.

Details and registration for the Thailand seminar are here: registration closes on March 4.

Monthly Turfgrass Roundup: January 2016

Here's a roundup of turfgrass articles and links from the past month:

Paul Jansen with a top 100 list of courses you may not have heard of but must play:

Edwin Roald on seven health benefits of golf.

Photosynthetically active radiation for 365 days at Tokyo.

Tokyo 2015 avg PPFD by hour and DLI

Handouts from the Northern Green Expo about turf nutrition, water, and light.

Zoysia tennis courts at Kawana:

Kreuser on simplifying soil test interpretation for turf.

Can one calculate how much water is required for a given area? Yes, here's how.

Growth potential (GP) and growing degree days (GDD): are they comparable?

Jason Haines with this report of 2015 pesticide use.

Breeden, Brosnan, and Vargas on how turfgrass herbicides work.

Haines on the best time to irrigate putting greens.

Course conditioning guidelines for PGA TOUR tournaments.

Albert Bancroft using a sandpro to help melt snow on greens:

Water quality for irrigation, questions and answers.

For more about turfgrass management, browse 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 are here.