"Is there a particular reason why you think it's a poor way to fertilise?"

A correspondent wrote:

"I'm hoping to get your thoughts on something I came across today.

I was discussing greens fertilising whilst at a friend's course this morning. He went on to get his new toy, the [...]. He's started to use the salinity level reading as an indicator to fertilise. So he's found a number that he's happy with that the turf looks hungry, applies a granular fertiliser and then waits for the number to drop back down to his threshold number again and repeats.

I'm not sure about this method as I've never come across it before plus I've never really looked into the salinity levels of my soils. I would just prefer to use gp and feel for when the plant needs something and adjust accordingly. But maybe he's onto something.

I would love to get your feedback on this if you're not too busy."

I replied that "I think that is a poor way to decide when to fertilize. Or what to fertilize with."

Then came a few more questions:

"Is there a particular reason why you think it's a poor way to fertilise?

If he's getting the results he desires, does that still make it poor? A reason he gave me about fertilising with a granular is [...] that by fertilising this way, he will encourage his perennial poa rather than poa annua."

First, the idea of deliberately managing soil nutrients to fluctuate up and down seems like the opposite of what most turf managers would like to accomplish.

I think most would ideally try to keep nutrient supply and growth as consistent as possible, rather than trying to cause them to fluctuate.


Second, it's changes in N that make grass grow, and then P and K and Ca and Mg and all the rest get taken up by the grass according to how much the grass is growing. So it makes sense to know the quantities of nutrients supplied, and also the quantities of the nutrients in the soil. But measuring the salinity of the soil doesn't tell which nutrients are there. It just gives the total quantity of salt.

Third, I have some concerns about the salinity number itself. The soil moisture meters that measure electrical conductivity at the same time are measuring the electrical conductivity of the water in the soil, and that measurement is strongly influenced by the amount of water in the soil. When the soil is drier, the meters give a low electrical conductivity reading, and when there is more water in the soil, even though there is no salt added, the electrical conductivity goes up.


This chart shows some measurements I made over a four day period on test plots on a golf course nursery green (pictured above). On a Sunday, I measured the soil VWC and the EC. Then I added irrigation water with 137 ppm salt, and I measured soil VWC and EC again. On Tuesday, there was a typhoon with 121 mm rain. On Wednesday, I measured the VWC and the EC again.

The EC as measured by the soil moisture meter is influenced by the water content of the soil.


One might say that is useful, because it gives some idea of the EC as the plant sees it. But if one makes that argument, then it is difficult to simultaneously make the argument that the EC is a useful criterion for determining when to supply fertilizer, because it is clear that the EC measurement is affected by the soil water content independently of the quantity of nutrients in the soil.

It is possible to adjust the EC measurement by incorporating the soil water content and the EC into a unitless measurement. The salinity index can be obtained by taking the EC, dividing it by the VWC, and multiplying by 100. This value takes into account both the EC and the amount of water in the soil at the time the EC was measured. There is not such a direct relationship between the VWC and the salinity index. But for those same data as shown in the previous chart, the salinity index also shows higher values with more VWC, even though no salt was added. In fact, after the typhoon's 121 mm of rain, one might expect leaching of nutrients, and a lower salinity index. But the opposite happened here, as shown in this chart.


And fourth, the follow-up question about if he's getting the desired results, is that still a poor way to fertilize? If he is getting the desired results, then fine, keep doing it. At some point it comes down to personal preference, because one can get good results in a lot of different ways. My preference, and what I think is a better way to determine when to supply fertilizer, involves monitoring the grass conditions, supplying N to produce the desired growth rate, and ensuring the grass is supplied with enough of each nutrient to meet the grass requirements. I expect such an approach is easier and will result in lower nutrient applications.

And about perennial Poa vs annual Poa, I'd be looking to supply a consistent amount of nutrients to the grass, rather than a fluctuating amount, because I expect the more ruderal biotypes of Poa annua would be more competitive with fluctuating nutrient supplies and with periodic granular fertilizer applications.

Turfgrass roundup: May 2017

Billy Crow asks how do I know if I have a nematode problem?

MacKenzie's fundamental principle of greenkeeping.

Paul Jansen with an amazing video of greenkeeping in Myanmar:

Bill Kreuser wrote about PGR over-regulation on golf green collars.

See how irrigation requirement changes with daily soil water balance in the Philippines.

How can a location with more rain also require more irrigation?

Doug Soldat with more surprising photos, this time of dandelions:

Brad Revill reports on eight months of MLSN.

My 2017 workflow.

Kreuser with more PGR info:

Jason Haines thinks we can do better than organic.

Four seminars about soil test interpretation in Australia.

Is this the best backdrop in golf?

Sue Crawford with an update from the MLSN green.

The two green system in Japan isn't always about summer and winter greens.

Are you subscribed to the ATC updates mailing list? Or the MLSN newsletter list?

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.

How much N is in rain and snow?

I was having a discussion about this last week. "I think it is a tiny amount," I said, "although sometimes I hear really large amounts when people tell me how much N comes in rain. I'll be sure to look it up." I just looked it up, and it is generally a small amount, although there are locations with more.


There are some excellent sources for N deposition data. I looked at:

For an example, I downloaded data for Benton County, Oregon, and Garrett County, Maryland. Compared to the amount of N used by grass, or applied as fertilizer in a year, this isn't very much. I'd guess annual N rates would be about 10 to 15 g/m2 at those locations. Adding 0.1 to 0.3 g N/m2 would be less than 3% of the annual N rate.


This guide has some maps that show the N deposition by location. There are a few hotspots that may get 20 kg/ha; that could be a substantial amount of N, say 10 to 20% of the annual amount used by the grass.

I looked up data for Tower Bridge in London using the APIS site. That was an annual total of 15.7 kg N/ha. That will be a substantial amount of N for turf in that location. I'd say that would be about 20% of the amount a golf course putting green might use in London.

Of turf, roots, and fertilizer

I'd like to make three points.

1- Surfaces can be great, and the roots can be negligible.


If the objective of greenkeeping work is to produce the desired surface, then one only needs enough growth to produce that surface. One also only needs enough roots to produce that surface. Any aboveground growth beyond that required to produce the surface is unnecessary, even problematic. For roots I won't go so far as to say extra ones are problematic, but I might say roots beyond those needed to produce the desired surface conditions are irrelevant.


2- Surfaces can be awful, and roots can be amazing. I've seen some incredible roots on some surfaces that didn't come close to meeting the level desired.



I'd rather have good surfaces than amazing roots.

3- I've been reading about an increase in roots and a simultaneous reduction in organic matter. Jerry Kershasky and I had a recent conversation about this:

Let's say one generates massive roots. Like those on the poor surfaces in section 2, above. Or by increasing the N rate (an easy and underrated method for stimulating root growth) as shown in the precision fertilisation guide from STERF.


How can one generate massive roots and at the same time reduce soil organic matter over time? I suggest it is impossible to do both. In the short term I can see where one can do that -- I've seen it myself. But long term, how can increasing the organic matter through production of more roots than would otherwise be produced lead to less organic matter in the soil? I'm not that credulous.

The two green system usually means there are two bentgrass greens per hole

The idea that golf courses in Japan with the two green system have a summer green and a winter green is not quite correct. Nor is the two green system used exclusively with one warm-season grass green and one with cool-season grass.

image from c1.staticflickr.com
Trevor Dormer and I had a brief discussion about this.

Survey data I looked at some years ago showed 37% of courses in Japan use the two green system. That number will be slightly lower today. But I expect most courses with the two green system will have two bentgrass greens. It does vary; a busy course near Tokyo has one Champion ultradwarf bermudagrass green and one korai (Zoysia matrella) green. And there are courses with one bentgrass and one korai green. I've written about this a lot. A selection of posts on this topic are at the bottom of this page.


But for now, here's what I saw on a recent trip to Japan. When I visit golf courses and talk with greenkeepers, I often ask these questions.

  • How many holes, one or two green system, and what grasses?
  • How many maintenance staff do you have?
  • What is the number of rounds at this facility?
  • How much nitrogen do you apply per year to the greens?

Of the nine facilities I visited last week, here's the answers to those questions from the greenkeepers. Six gave the N rate. The minimum was 11 g N/m2/year, the maximum was 20 g, and the median was 13; 3 greenkeepers didn't have the number off the top of their head. The other data are in this chart.


The median staff was 15 people, and that includes everyone -- mechanics, part time staff, office staff, etc. This is actually a bit high for Japan. I was visiting facilities skewed a little to the high end. I think the nationwide average staff will be 12 or 13 people per 18 holes.


The median rounds were 44,000 per year. That seems about right. The course with 80,000 rounds has night golf and one can tee off until 21:00.

And how about the greens? I visited 9 courses. Of those, 2/3 had two greens. Of those with two greens, 1/3 had one bent and one korai, and 2/3 had two bent.


More about the two green system in these posts.

"It has been around 8 months since we started following the MLSN guidelines and ..."

Brad Revill wrote about his use of the MLSN guidelines, some of the adjustments he has made, and reports on how it is working.

"So it has been around 8 months since we started following the MLSN guidelines and we have been very happy with the results, not just from a turf performance point of view but from the financial side as well!"

That's the idea. Turf performance should be the same, or better, than with other methods, because MLSN recommendations are based on supplying the grass with all the nutrients the grass requires.

"Some of you may be asking 'What about root growth?' Well I can only tell you from my experience following the MLSN over the past 8 months is that we have seen a steady increase in root depth over the last 12 months"

I'm glad to hear that. Eli Rahz shared something similar last week:

And for cool-season turf, I'm reminded of the Poa annua roots Sue Crawford showed last autumn:

Good stuff. It's fun to see those results.

Soil test interpretation and more: 4 seminars in Australia

I was in Sydney, Adelaide, and Brisbane this week to discuss the MLSN approach to soil test interpretation in four seminars organized by Living Turf.

In these seminars, I explained that the use of the MLSN guidelines is as simple as planning how many beers to buy for an upcoming party. And at this party, I want to ensure that I don't run out of beer to serve my friends.


This is a quick summary.

1: Soil test calibration involves establishing different levels of nutrients in the soil, growing a grass in those soils, and then evaluating the grass response to different levels of that nutrient. It quickly becomes apparent that these calibrations will be specific to the soil type, grass variety, and climate in which the calibration is done. Doug Soldat called these tests "expensive and time consuming." On a global scale, the word I use to describe this is impossible.

2: Because doing such extensive calibration is impossible, the conventional turfgrass guidelines were developed by adjusting the ranges from agricultural crops and soils:

"Traditionally, ranges for various nutrients are based on the past 60 years of fertility studies, particularly on forages, agronomic and horticultural crops, with adjustments made to fit perennial turfgrasses based on studies and the judgment of experienced university turfgrass scientists."

In addition to that, the conventional guidelines have in some cases been set deliberately high. That's not because grass performance would be improved by more nutrients, but because "the cost of fertilization was not considered of primary importance for turf." And that quote is right from the textbook.

3: The minimum levels for sustainable nutrition (MLSN) guidelines for interpreting soil tests take a different approach by focusing on the way turf is managed in the modern era, and considering grasses and the soil conditions used for high performance turfgrass today.

4: Use of the MLSN approach involves making an estimate of 100% of the nutrients that the grass can use, and increasing that by an additional amount to keep as reserve in the soil. One then compares the sum of the use estimate and the reserve quantity to the amount actually present, and the result of that comparison is the minimum fertilizer recommendation.

You can scroll through the slides below, or view or download them here.

After my seminar about MLSN, Daryl Sellar showed a demonstration of the TurfKeeper system. One can read about it at the website, and how it "becomes the home of all turf management planning, actions, and facility history." It starts with a job board and goes from there, with the tasks, costs, product usage, and application records all linked in a way that impresses me every time I see how TurfKeeper is used. I was recently listening to a podcast about turfgrass innovation. Dave Wilber and Kevin Hicks discussed the direction of the industry, and Kevin mentioned that there is a lot of data out there, and a lot of systems that do a good job of handling one aspect of the data. TurfKeeper puts it all together in a way that few others do.


The MLSN approach is suitable for any grass, soil, and use, because it involves both a site specific estimate of nutrient use plus a reserve amount to keep in the soil. I enjoyed seeing a range of turfgrass sites and grasses on this trip, and discussing with so many turfgrass managers the practical use of MLSN to interpret soil tests in those conditions.


That's kikuyugrass at Eagle Farm race course in Brisbane. For a good story about something that happened at Eagle Farm in 1984, read about Fine Cotton.


This is Legend green couch (bermudagrass) overseeded with perennial ryegrass at Suncorp Stadium.

A post-conference assortment

I made a few notes at the recent Philippine Golf Course Management Conference. I was there to speak about irrigation water and soil test interpretation.


The conference program was excellent and I learned a lot. Things I noted, which will perhaps be of interest:

  1. Do you know about this sand calculator from Purdue University?

  2. One of the speakers showed how the Turf Tracker improves the precision of product applications to the golf course.

  3. I was intrigued by the Zero Carbon Resorts program, and especially the Demonstration Cottage.

  4. There was some discussion of the Philippines Köppen climate classification.

Turfgrass roundup: April 2017

Easily identify four tropical grasses.

Paul Jansen on a "Sustainable by Design" tour.

Photos and presentations from the R&A Sustainability Seminar in Japan.

Website visits by computer, phone, or tablet.

The GP Avatar app from PACE Turf.

Andrew McDaniel set off a long conversation with this tweet:

An MLSN refresher.

K in phosphite/phosphonate products.

Snow at St. Andrews from Gordon McKie:

Spring, cherry blossoms, and a 1200 year time series from Kyoto.

Andrew McDaniel went inside the ropes at the Masters with Yuta Ikeda:

Update from Oregon: S, Ca, and microdochium patch.

Ricardo Llorca prepares a multifunctional facility:

A map of MLSN newsletter subscriptions in 33 countries.

Are you subscribed to the ATC updates mailing list? Or the MLSN newsletter list? 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.

What's my workflow? 2017 edition

Five years ago I wrote about my workflow to keep up with turfgrass information. From 2012, Productivity 1: what's my workflow? and Productivity 2: my turfgrass information workflow

In the first part, I explained that I used

  • two notebooks
  • Google Reader
  • judicious use of Twitter
  • occasional use of Evernote
  • and one list of work to do.

Then in the second part I explained how I did it.

A lot of things have changed since then. I generally use just one notebook now, Google Reader doesn't exist anymore, I still use Twitter, I haven't used Evernote for years, and I still keep one list.


Here's what I'm doing in 2017.

I want to accomplish as much as possible, and I want to keep up with turfgrass information. I don't want to miss anything I should be aware of, and I also want to keep track of what I'm working on and keep that work moving forward.

I'm still using the Getting Things Done (GTD) approach.

1 list: On my computer, I keep a master list of all the projects I'm working on. Five years ago I was using OmniFocus for this. Now I use Org mode.

1 notebook: I keep a small notebook with me for ideas, calculations, and notes. I still have a large notebook that I use when necessary, but I often leave it at home. Then I transfer the notes from my notebook to the master list on my computer during my weekly review. I've been using small notebooks from LEUCHTTURM1917 for the past couple of years. I like them better than the Moleskine notebooks I had been using.

My phone: It's not easy to write or do my work with a phone. I use my phone for communication and a little bit of reading. I don't bother with Evernote anymore. I use the built-in notepad app to make a note if I have to, and if I don't have my notebook. Then, I transfer the note to my master list during my weekly review. No Facebook on my phone. Notifications from all apps pretty much turned off. No e-mail on my phone. Well, I can get to my e-mail if I have to, but through webmail, which is such a hassle that I won't check it unless it is an emergency. I have Twitter on my phone, and Buffer. If I have things I want to share on Twitter, I'll sometimes share immediately, and sometimes use Buffer to post them later. I get a lot of questions about things I've written about on my blog, and I figure that if one person has a question about something, others may also. So I sometimes set an old blog post to post sometime in the future using Buffer, when I have used that blog post to answer someone's question in a private conversation.

1 weekly review: Once a week, on Friday afternoons if I can, and otherwise at the next available opportunity, I review my notebook and phone, transferring any new tasks or projects into my master list. During the review I go through all my active projects and update what's been done and what my next actions are.

Twitter: This is still pretty much the same as I wrote in 2012:

"I make judicious use of Twitter. I'm able to share information about the articles I've written, or new information that I've made available for download, and I also find interesting articles and information from the people I follow. I don't read everything that comes through on the Twitter stream. There is no time for that."

What's different now? I use Tweetdeck on my computer, and Buffer on both my computer and phone. With Tweetdeck I can see the stream for a few hashtags -- among them #MLSN and #turfchat, and searches for zoysia and for paspalum. Then with Tweetdeck I can quickly see the latest tweets in those categories.


Feedly: I used Google Reader until it was killed, and now I use Feedly for RSS feeds. When websites update, it goes to Feedly. Then I can read the update at my leisure, or delete it. I don't have to go searching for information. The information comes to me, just like e-mail, and I can read it when I'm ready. Turf researchers find the TGIF feed of recently added articles especially useful. I don't have to remember to check any of the sites I follow. I don't have to check Twitter feeds or sign up for e-mail alerts to find when a new blog post is up. It all comes to Feedly.

Google Scholar alerts: I have a few Google Scholar alerts set up. For new citations of my articles, keywords like "turfgrass and potassium," some grass species, and new articles by a few other researchers. I then get a notification e-mail with a link to the articles as soon as Google Scholar adds them.

That's my workflow at present. And when I am working on my computer, I'm generally using RStudio. I wrote the MLSN paper in RStudio, make most of my presentation slides in RStudio, and do all data analyses in RStudio. I wrote this post in Emacs Markdown Mode. I write reports in Emacs LaTeX mode.