Our schedules have gotten all messed up, haven't they? I would have been at the Masters Tournament this week, and definitely not sending out an MLSN newsletter. Instead I'm at home in southern Thailand, feeling lucky that I can spend this time with family in such a salubrious location, and also feeling lucky to have the kind of work that I can do from home. To keep the next newsletter from getting too long, here's a substantial amount of new stuff about MLSN.
I'll be doing a webinar on May 22 (at 10 am Eastern time, UTC-4) with a title "How MLSN Works." I'm doing this for the Amplify Network of Brookside Labs. Contact Chris Eidson (firstname.lastname@example.org), the Educational Specialist at Brookside Labs, to register.
If you have any questions, concerns, complaints, or testimonials about MLSN that you'd like me to address in the webinar (or in an email conversation or blog), please send them to me and I'll try to include them.
New reading material
I wrote a short document describing four ways to determine nutrient requirements. I explained why MLSN has some obvious advantages to alternative methods. You can read the document here
John Kaminski has relaunched the TurfDiseases blog. One of the questions I sometimes get about MLSN is related to nutrients and disease. I wrote a post there, Diseases and MLSN, in which I said there is no relation between MLSN and disease. I included a quote from Management of Turfgrass Diseases by Dr. Vargas:
"The simplest solution is to maintain adequate levels of phosphorus and potassium and vary the amount of nitrogen."
That sounds exactly like MLSN. This is pure speculation on my part, but I'd expect that applying nutrients based on MLSN could reduce disease pressure, if anything, by ensuring the grass is always supplied with enough nutrients. MLSN, in particular, will avoid unbalanced nutrition, which can be a bad thing.
Research about MLSN
The SUSPHOS project is continuing this year, and you can read the latest report starting on page 18 of the STERF Yearbook. I've been involved with this project since the beginning and have enjoyed learning about the results. There will be a number of presentations and articles coming out about this project. A number of things are clear, however, from the results so far.
- When establishing creeping bentgrass from seed in spring, in sand with P lower than the MLSN guideline, the establishment is more rapid when P is supplied. Supplying P at 12% of the N rate—that's the amount proportional to grass use—was sufficient to get maximum yield. Phosphorus at 6% of N rate gave the same visual quality but not quite as much yield. This was true even in the cold temperatures (7, 12, and 17 °C) of spring.
- When trying to improve spring green-up and turf quality in the spring, established bentgrass with soil P slightly above the MLSN guideline did not have a response in green-up or in turf quality to added P, also in the temperature range of 7 to 17 °C. Adding P, up to a rate 13.5% that of N, did increase the clipping yield.
These results suggest that the current MLSN guidelines for P are reasonable levels in relation to turf performance. And the results also suggest that adding P during cool spring temperatures, either for new turf establishment or for encouraging green-up of established turf, won't improve turf quality if the soil already has sufficient P. Clipping yield appears to reach a maximum when P fertilizer is applied at rates proportional to the N supply and the standard leaf N:P ratio.
Well, not really MLSN, but nutrients in general. I've been growing some grass at home, in pots, applying nutrients to try to get differences for demonstrative photos.
You might think this grass looks really healthy. It does, actually. But I only fertilized it with urea for 6 months. A lot of urea, no P, and no K.
But compare the urea only grass to the one supplied with P and K too, and there's a big difference.
I don't often discuss cost or product choice. What I do focus on is quantity. How much of each nutrient is required, that sort of thing. It's interesting, in the case above of the grass grown in pots and fertilized with high rates of nutrients, to extrapolate those rates out over a larger area.
For example, the N-only pot was supplied with 45 g N/m2. To consider this in golf course terms, 1.5 ha (3.7 acres) would be a slightly larger than average set of putting greens for 18 holes. For 1.5 ha, to supply that massive amount of N from urea cost 17,550 THB. That's about USD $535.
This was a grow-in, so I put a lot of N to stimulate growth. I also wanted to demonstrate differences between N only and N+P+K, so I made sure to create a high P and K demand by supplying a high N rate. Realistically, in a tropical climate, this is about twice as much N as a green of this species might need in a year. So figure the cost could be half that, about $267 for a set of greens, per year. And in a part of the world with winter, where grass wouldn't grow much in winter, the annual N rate for this grass would be about a fourth of what I used. So the annual N cost for 18 holes using urea would be about $134.
Of course that N-only pot was deficient in P and K. What if we supply that same amount of N from urea, plus add more K than the grass can use from KCl, plus all the P (and some more N) the grass can use from DAP? Now the total cost, extrapolated to 1.5 ha, is 47,196 THB, or USD $1,440. In a tropical climate this grass would reasonably use half this amount in a year, so cost would be about $720. In a place with winter, the cost for N + P + K would be about $360.
I've heard from a superintendent friend who has had to take a pay cut; I've read of other facilities that may have to close completely. One way to save money with fertilizer is to use a method such as MLSN. This ensures that the only nutrients that are applied are those that are really required. Another way to save money is to supply those necessary nutrients using products such as urea and potassium chloride. That's where the big savings happen, actually.
Soil nutrient analysis
I (ATC) do soil testing and make recommendations for clients in multiple countries through Brookside Labs. Please contact me if you'd like to do any testing.
BRT also offer a full range of services through Brookside and interpret results using MLSN. I see they are currently offering a 20% discount to new clients.
Living Turf also can interpret soil test results using MLSN.
If you are a company providing soil test interpretation and fertilizer recommendations, and are primarily using MLSN to develop those recommendations, and if you would like to be listed in a future newsletter, please let me know.
I'm doing a review of the Global Soil Survey data at the moment, still playing around with the demonstration pots at home, including some growing in sand now, and I've been looking at soil test results for micronutrients a bit. Maybe I'll write about some of those topics in the next newsletter.
Thanks for reading. More about general turf issues at www.asianturfgrass.com, in the other ATC newsletters, or on my @asianturfgrass page.
Chief Scientist | Asian Turfgrass Center