Saturday, 23 April 2016

Finding the time to think

I will probably come at no surprise to you to learn that I think a lot about what I do at work. A few weeks ago Chris Tritabaugh shared a tweet with his followers (I'm one of them) that made me think....about how I think...I think?  The article explains how successful people spend a lot of time thinking and not actually doing physical work. Now I am in no way implying that I am successful. I think that is a rather subjective thing to proclaim. I do, however, spend a lot of time thinking about grass....and stuff.

When talking with other superintendents about how I blog the question often arises, "how do you find the time to blog?" The answer came to me when I read the above article about thinking. For me, blogging is thinking, it is putting what I am doing and thinking in writing. It just so happens that I share this with the world (that part doesn't take any time just guts). When I sit down to write a post it is during time of reflection. Times when I am making sense of my observations and data. It is these times that I reflect on the past and plan for the future. Part of being a good manager is planning for the future right?

From my own experience and from talking with other superintendents about it I think we can get in trouble if we try to physically do to much. How often do we hear about how we see the course in a completely different way when we golf it instead of drive around in a frantic furry trying to do everything we wish we had time to do? It is extremely important that we take the time to think, observe, and plan.

It is during times when I don't make time to think that I find myself getting into trouble. Things happen that require corrective actions and then I end up being like a dog chasing his own tail. This just isn't productive.

I also think that if you don't have a grass killing blog like me it would benefit you to maintain a journal. For me the act of writing it down helps me organize my often jumbled thoughts in a more clear way. Proofreading my posts 3 or 4 times often brings out further ideas that I wouldn't otherwise have time to think up.

Now if you think this is a waste of time think again. I estimate I have saved my club well over $100,000 in the past 4 years by thinking and blogging. I break even on that ROI if I spend 20 hours a week blogging and thinking for 4 years straight! I might spend 3-4 hours a week thinking and writing so my ROI for thinking is HUGE!

So the next time you ask yourself "where does he find the time" I suggest you make the time to tour your course and think about stuff. Schedule it. It's probably more important that edging those cart paths or weeding that garden and you might come up with a way to improve your operation. Even if you aren't improving or coming up with another crazy fusarium management scheme you might catch something early and save yourself a ton of problems in the future.

Thursday, 21 April 2016

Easiest Winter Ever for Fusarium. IPM on Steroids

We are now safely enough into Spring that I can reflect on the Winter fusarium battle. We aren't in the clear yet, though, as we have had to battle fusarium right until the end of June in some years. The recent record breaking hot weather has sure helped but as we return to normal April weather this week I fully expect the fusarium to make a resurgence.

As the title suggests, this winter was an absolute breeze when dealing with fusarium on all parts of my course. The weather was abnormally warm and wet but this didn't seem to make the disease worse as you might think. I have often hypothesized that it isn't the weather that makes fusarium bad during the winter, it's our maintenance practices that do.
Sorry, I literally have no fusarium to show you. 
I have talked and seen other courses that did not have the same luck as me. Of course no golf course is the same and there are a ton of factors involved. The reason I think I had such good success this winter is a combination of everything I am trying. I don't think any single thing I do on it's own will make a difference. I think it's a package deal. Also, this isn't the only way to succeed and I have talked with other superintendents who also had a good winter with a different approach.

Good weather helps

Recently I have found a lot of people telling me that my disease success is because of a healthier soil or a bunch of other feel-good ideas. Firstly, there is no way for me to measure that, and I know that there are a lot of things that I am doing that has nothing to do with "healthy" soil that have an impact on fusarium in the winter.

So to recap the winter starting Oct 1 2015;

  • 3 broadcast fungicide applications; Low rate Banner app Oct 23, Low rate Heritage app Jan 19, Low rate Interface app Feb 22. I won't be surprised if another app is needed before May 1 2016 now that the cooler "normal" weather has returned, but who knows? 
  • Spot fungicide applications every 3 weeks or before mowing to get active disease spots.
  • Regular Phosphite applications on a 250 GDD application interval.
  • Since the beginning of Oct 2015 until beginning of May 2016 I will have only applied 2.3g N/m2 (0.47#N/1000 sq. ft.) Read more about how I fertilize so low here.
  • In same time frame I applied 2.5g Sulfur/m2 so that's a 1:1 N:S ratio. I use ammonium sulfate as my nitrogen source for all surfaces during periods of fusarium activity for this reason.
  • I applied 2.4g potassium/m2 so a 1:1 N:K ratio. 
  • I mowed greens less than 20 times from beginning of Oct through to end of April. We went 107 days without mowing from Nov 3rd 2015 to Feb 20 2016. I also try and time mows in the winter for dry cuts although that's not always possible. We schedule mows based on clipping yield. Read about that here.
  • We rolled greens 50x from beginning of Oct through the end of April. I've observed that rolling doesn't spread disease like mowing or verticutting and could actually reduce it similarly to how it reduces dollar spot.
  • I regularly topdressed greens to bring the sand up to the leaf tips instead of cutting the leafs down to the sand. This kept my greens firm and smooth all winter with less mowing required.
  • I kept greens fully regulated with Primo Maxx through winter.
Each of those things is aimed at managing fusarium in the winter without impacting playability on greens. We had a bit of bad disease on our shadiest green but for the most part the greens overwintered in perfect condition. Having said all of the above, the fairways also survived the winter well. They got low rates of N with similar rates of sulfur and no K for the past 3 years and we didn't mow them either. Fairways are a completely different beast than greens though.

So it's pretty clear that my disease management success has little to do with the feel good idea of "healthy" soil.
  • I still needed 3 broadcast fungicide applications. I probably prolonged their control by growing grass slowly. Less product was removed via mowing.
  • I battled disease spread via mowers by spot spraying active disease spots, by mowing as little as possible, rolling, topdressings, and keeping the grass growing as slow as possible with growth regulators and low N fertilizer rates.
    I'm still on the same 4L spray mix for 2016! A little goes a long way.
  • I applied sulfur at a 1:1 ratio to N. It's well known that high N generally makes fusarium worse. It is also well known that high rates of sulfur can reduce the severity of the disease. The sulfur probably helped reduce the disease this winter.
  • Phosphite! It works! One of the big benefits of it is that when disease does hit, it hits slower. This allows me time to think, react and make a pesticide application appropriate for the conditions. I can also wait it out a bit longer for better weather instead of being forced to make an application in less than ideal weather. This year phosphite has accounted for 60% of my total EIQ.
  • As I use the growth potential formula to determine my nitrogen rates. I also applied a lot less K during the winter months which some recent research has shown to reduce the incidence of fusarium patch during the winter. With GP, over 90% of the K is applied during June, July and August each year.
Image Credit: Doug Soldat, Turfgrass soil, nutrition and water specialist at the University of Wisconsin-Madison Twitter: @djsoldat

So you might be thinking I'm being a Debbie Downer here as far as healthy soils etc, but in order to learn and move forward we need to look at the facts and even though I don't think my healthy soil has anything to do with it. There are still a lot of positives for me this winter.
  • The greens made it through the winter in good condition, this is the main thing. There is little point in reducing pesticides if you are left with dirt in the spring. This is one of my biggest beefs with blindly going "organic" as I shared in an old post here.
  • 2 products, Iprodione and chlorothalonil, are going to be restricted in Canada and I only needed 1 app of iprodione this winter. If I can repeat my success in future winters this restriction should not impact my operation negatively. I can't say the same thing for other courses with actual winters but I can't also say that some of the things I am trying won't also bring successful results for those with real winters such as low K in the fall. Even though I used iprodione this winter that doesn't mean that it was required. Maybe I could have gotten by with a lower EIQ product? I will never know.
  • I used less traditional pesticide. In the realm of public opinion this matters a lot. I can honestly say I have cut my traditional pesticide use by up to 70% over the past few year. Of course the educated know that's not the entire story, but does that matter or does the public's perception matter more? It's an issue I struggle with every day.
  • It was easy!! This can't be understated. I wasn't chasing my tail trying to get control. This has left me with no urgency going into the spring growing season. There is nothing to recover from and I can continue to keep things lean and mean. There's nothing worse than being caught with your pants down with disease in the winter. I've been there, done that and it is not fun. If anything I could have gone by with probably less pesticides but at the time it's always hard to know that. Maybe in future years I will be able to further make reductions with a slightly higher tolerance for disease on my greens because they are honestly very clean, too clean (knock on wood).
Last year I was able to reduce my EIQ (environmental impact quotient) by almost 40% and costs by 30%. This year I set my goals to what I achieved in 2015. A total pesticide cost (course wide) of $3000 and an EIQ of just under 600. That's an EIQ equivalent to 2 light rate chlorothalonil apps or 1 heavy one!  This is why I think organic is silly; We can make huge impacts with new low EIQ products and better IPM (integrated pest management) practices all while keeping conditions great. I don't think you could get costs or EIQ this low with purely organic practices. I think I might be approaching the sweet spot for both cost and EIQ for disease control at my course. 

So why not work towards my best year ever instead of the old normal? If you want to learn more about how I track pesticide use check out this post but please remember that since the time of writing that post I have learned that the EIQ is slightly flawed. Even so, it is still the best way that I have found to measure the impact of pesticides.

Do you track pesticide use in a meaningful way?

So taking the big reduction in both cost and EIQ goals for this year you can see that I am slightly behind on my cost and EIQ goals. I'm not worried though, as the only real disease issue I face is fusarium so if we have a dry summer I will gain ground during that period. BIG IF! Even so, it's pretty cool that I am again on track with my lowest costs and EIQ ever. Doing it once is nice but repeating it consistently is the end goal.

Looking back I am confident I know why I had success this winter. It's not from the feel good reasons some people might want to believe, it is because I have planned my ENTIRE operation to manage this specific turfgrass disease while impacting play as little as possible. This is what IPM looks like. IPM isn't just one thing here and there, it's everything I do. Miss one step and I don't think you will have success similar to me. The real end result is that no one notices all this hard work. There is no compromise for the golfers, those who fund my turfgrass addiction, so I can kill grass another day.

Happy fusarium farming!

Tuesday, 19 April 2016

Controlling Growth Rates

I've been measuring clipping yield on my greens for the past 5 years. The reasoning for this is to get a good idea of how fast our grass is growing. After all, this is one of the most important things to know as a greenkeeper as described in Micah Wood's book "A Short Grammar of Greenkeeping" which I highly recommend you buy. In it he defines greenkeeping as "managing the growth rate of the grass to create the desired playing surface for golf. All of the work done to the turf is centered around managing how fast the grass will grow. This is consistent across all parts of China. And the best golf course conditions will be created when the superintendent is able to create just the right growth rate."
How fast is your grass growing?
The more I learn about our profession the more I agree with this statement. When I was a young superintendent the growth rates of my turf were all over the place. We were hit with huge growth flushes without notice and were left chasing our tails trying to get everything mowed in time. We had huge issues with grass clippings, thatch, and other turfgrass growth related issues (hint; it's all related to growth). In the past few years as I have learned to manage the growth rates of my grass better by using the growth potential formula to schedule fertilizer rates we have had far less surprises when it comes to growth rates of our grass. We have also had less surprises when it comes to disease, green speed issues, water management and pretty much every other aspect of our golf course management operation.

With growth potential we aren't fertilizing the course based on the date on the calendar. We are basing it on actual conditions. This takes a lot of the guesswork out of fertilizing grass and allows you to accurately predict how the grass grows. If you want it slow, you grow it slow (like I'm doing). If you want it fast you can grow it consistently fast as well. It all depends on your needs,
Slow growth rate = fast, consistent greens
This week while looking over my growth rate records I noticed that this year we have been able to keep our growth rates low and more importantly consistent despite the weather being abnormally warm for this time of year.

As you can see below, we were cutting a frequency of every 3 or 4 days starting right at the beginning of February. This time (mid April) last year we were cutting daily to keep up with the growth rate explosion.

This year, despite the extremely wet and warm conditions, we have been able to only cut every 4 days starting in late March. This was following a period of 107 days where we didn't mow the greens at all. When we finally did mow the greens on Feb 27 we got almost no grass! The growth rate has also been very consistent this winter.

We are now in mid April just before the time when we historically get a big growth flush. I'm not sure whether or not we will get it this year though because we have had weather similar to mid July for the past few weeks and still, growth remains minimal.

So what am I doing different this year than in previous years?
  1. Diligent growth regulator use through the winter. I did not allow the turf to come out of regulation at all this winter. We also did not let off the applications for our "aeration" which consisted of only a medium topdressing as we had aerator issues and I was already questioning the need to aerate in the spring with the low growth rates we have been having.
  2. We aren't pushing growth. In previous years we have had issues with disease on our course but for some reason I'm not 100% sure why we have had almost no disease pressure this year. 
  3. In 2016 we have only applied 0.96 g of nitrogen per square meter (0.2#N/1000sq ft) until the end of April. In 2015 we applied double that. It wasn't until last May that I decided to see what would happen if I cut the amount of N I applied to my greens in half. So far I consider this decision a success but time will tell. The greens don't look like they normally do but they play great and have only required 3 fungicide applications since the beginning of October! I am watching the greens closely for signs of wear but so far we haven't had any issues even though we have been rolling daily (or twice daily) for the past month.
Those of you who have an extra keen sense of observation might notice that in the past we used "basket empties" to measure the amount of clippings collected where this year we use liters. This was at the recommendation from Micah Woods because liters is a more accurate way to measure clippings that relies less on someone's perception on what constitutes a full basket of clippings. Objective vs subjective.

Measuring clippings doesn't have to be a big chore but and there are a few things you can do to make it easy and the most useful to your operation.

We only collect clippings from the middle mower on our triplex on 2 of our 12 greens. This is because it doesn't really matter what the total amount of grass collected is, we just want to have something to compare day to day. One of our greens is too small to gather enough grass for a good measurement so we use 2 greens. We only collect from the middle mower because we sometimes do a circle cut which would augment the clipping yields on those days. By using the middle basket we reduce the impact of this slightly.

We just hang the measuring pail on the mower. Operators make sure the baskets are empty before we cut our 4th and 7th greens (they are close together) then empty the contents of the middle basket into our measuring pail when they are done mowing those 2 greens. After they finish mowing they put this number into the equipment use form and this is automatically fed to my growth rate spreadsheet as seen in the above images.

Measuring the growth rate of my grass has been one of the most enlightening things I have done over the years. We often overlook the importance of collecting good data about what is actually happening on the course. We can get a good idea by just looking at the grass but without measuring and recording this data we make it difficult to learn anything from it in the future. As Micah outlined the importance of controlling growth rates I could talk forever about the benefits of this. Less wear and tear on machinery, less traffic stress from mowing, less thatch, less grinding reels, less labor, less fuel burned...the list is almost endless.

Sunday, 10 April 2016

Reasons to Not Aerate in Spring

I'm going to try and talk myself out of aerating in the traditional way each spring. Won't you join me?

Last year I asked "Is Core Aeration a Thing of the Past?" This year I am wondering if solid or core aeration where sand is worked into holes is needed at all? Here I will try and find some reasons why I should and should not aerate my greens in the spring time. Before we start I'll go over the traditional reasons to aerate and then I will discuss why I might be able to get those benefits in different ways.

Traditionally we core aerate to remove organic matter, reduce compaction, increase soil air and increase drainage. That's pretty much it. Core aeration and filing solid holes with sand are two ways to do this but surely there has to be other ways especially with the new developments we have made in the past 10 years or so?

For the past 3 years we have been deep tine aerating our greens in early October. This was because we had developed some troublesome layers that were below the reaches of traditional aerators. These layers were significantly impeding drainage and the result was a lot of difficulty keeping our greens dry. Since then, we have had almost no drainage issues on our 30 year old greens. The only puddling we have seen has been following a 4" rain event in mid December of 2015. Other than that they drain great! So as far as drainage goes I think the regular deep tining should have us covered.
Now we're talking
So we deep tined last fall but on the West Coast of Canada there isn't much growth through the winter. There is even less growth when you use the growth potential formula to schedule fertilizer applications and keep the grass growth regulated with Primo Maxx all winter long. Since we aerated last fall, we have only cut our greens 13 times! That's 13 mows in 175 days! We have had so little growth that on some of the greens you can still see where the aeration holes from last fall were. It doesn't make much sense to me to aerate again immediately after the holes from last aeration have finally healed fully.

Last year I applied about half as much nitrogen as in any year prior. This was done with the help of the growth potential formula as I shared in my last post. So far in 2016 I have only needed to apply 0.6g n/m2( about 0.13# N/1000 sq. ft.) I have never been a fan of pushing growth around aeration to close up the holes. This seems counter-intuitive to me. Remove organic matter then push growth and consequently build up organic matter in the process? If I only aerate in the fall I am not pressured to get the greens in good playing condition in a short period of time. I can leave the holes open for much longer in the fall thus increasing the benefits of aeration further. If we are producing less organic matter through less growth there should be less need for removing organic matter with core aeration.

I think often we do things in Canada because our neighbors to the south do them. The thing is that a lot of the courses in the USA have growth all winter long and therefore need to aerate a lot more. Is this the case in Canada? Should we base our aeration practices more on how much growth we get based on our specific climates and not as much on what others do in their specific climate?
Greens growth and mowing data since last aeration. Not much..... Replace basket empties with liters
One of the biggest down sides of aeration that often is ignored is preferential flow. Basically when you poke holes in a green and fill them with sand, any water that is applied to the green flows down the nice free draining holes. This leaves the other soil areas of the greens suffering from much less, if any water flow. As nutrients need water to get into roots this also creates problems with fertilizer uptake from the soil. This creates stagnant conditions that always results in the turf surrounding the holes suffering. Often we associate the nice green grass in the new aeration holes as a sign that aeration works. I see the suffering grass surrounding the new holes as a major down side of aeration. Instead of having the water flow great through a limited number of holes, I would rather it flow evenly through the entire soil profile. This is why you always flush salts before you aerate. Of course, we will have to do things to keep the flow rates high, but I think this can be done without filling holes with sand. We regularly needle tine aerate our greens to help with surface drainage and gas exchange. Is this enough?
 Deep thought of the day; Is the grass greener because of aeration, or is the grass less green because of aeration?
Preferential flow, it makes you think....
One of the most difficult times to manage disease on the West Coast is the spring. The other difficult time is early fall. The rest of the year I have found disease management to be relatively easy. For this reason I think it might be important to limit practices that make disease worse during the challenging weather conditions. Things such as pushing growth, dragging sand around, pulling cores and scraping them off the surface, and creating areas of weak grass through preferential flow area all things that have the potential to make disease issues worse. I think there's a good chance that I can get through the spring without a broadcast fungicide if I don't do an aggressive aeration.
My new 4L (1 gallon) spray rig. 
This year the poa is starting to seed about a month earlier than normal (what is normal anymore?). The poa is stressed and doing an aggressive aeration will only stress it out more. The timing of spring aeration on the Coast is not ideal. Fall is much better as the poa isn't seeding and stressed in this way. Opening up the greens during this seed head cycle might also be a big reason why we have so much poa on greens. Even though I'm not aggressively trying to promote bentgrass, I have noticed we have had a lot more bentgrass spread on our greens lately and anything I can do that further promotes the bentgrass isn't a bad thing.

Lots of bentgrass this spring.
Part of my management program this winter was to not grow much grass. This would require less mowing and therefore would result in less stress and disease spread on the greens. Part of this plan to limit mowing was to continue regular topdressing through the winter months. Instead of cutting the grass down the the crown, I would add sand up to the leaf blades to accomplish the same thing as mowing while also diluting any surface organic matter. With our old topdresser we literally couldn't apply sand light enough to not cause a major disruption. With our new topdresser we can apply it as light as we want. This is a game changer and one of the reasons why I am re-evaluating our old way of aerating our greens.
Dilution is the solution to pollution
I have also never really aerated the fairways here. We have once or twice since 2007 but the holes were too few and far between to have any real impact, other than dulling my mowers. Since we have stopped aerating our fairways they have only improved! Again, with a growth potential based fertilizer schedule on fairways, we have been able to better time our nitrogen applications on our fairways and this has resulted in much less thatch. This has been so successful that we now have virtually no wet areas on the course despite having a very wet winter with over 1000mm (50") of rain. Where we used to spend a lot of time and money fixing wet spots, we now are spending a ton of time pulling rocks as the thatch that used to pad them is now gone. Even though it's not wise to compare greens to fairways, this example shows me that not aerating is not the end of the world.
Despite no aeration, we are able to grow good grass on our fairways during challenging growing conditions (record drought last summer)
Next to useless especially on extremely rocky soils.
During the winters we also get lots of good natural aeration. Frost heaving and heavy rains help flush the soils and leave them nice and fresh come spring. With the drop in winter traffic the greens also get a nice break to recover during the slow growth time of year. Why then do we need to aerate in the spring following an extended (6 month) period of rest? I can't speak for everyone, but at my course, winter is a period of rest. I guess if you had a ton of play during the winter you might need to help them out a bit.

Of course there is also the disruption to play in the spring. Just as conditions improve from the winter, we go back to square one. Aerating in the fall is far less disruptive to business as most people are starting to go south and are tired of golf. Why should we disrupt play early in the season when everyone is excited to get out and play if it's not 100% necessary.
Finally the course has recovered, then why do we rip it up again?
Just like everything I like to try and see both sides of the equation. So why should we aerate in the spring? What are the good reasons that I can find that justify the need to undertake this disruptive practice?

The biggest reason is that we have always done it this way. Yeah yeah, that's a bad reason but for the most part, we have aerated in the spring, and have lived to golf another day. The big thing here is that we have done it and have managed to keep grass on our greens. Was it because of spring aeration or despite it? I don't know because we have never not done it. Others have but they are few and far between.

So what's the plan? What would I do if I stopped doing my regular spring aeration? Well for now I am thinking of only coring my aprons and approaches. The reason for this is that there is overlap in fertilizer applications on these areas thus more growth and need to remove organic matter. We also want to prevent collar dams from forming as the sand that we do apply gets caught more in the longer grass surrounding the greens leading to buildup. Removing more material than we add will reduce the collar dams over time.

After that we would add a light (but slightly heavier than normal) topdressing followed by a needle tine aeration. Then we would just go ahead as normal. Regular light topdressings every few weeks and needle tine aeration as needed to keep air and water moving through the soil surface. Then a deep tine aeration in the fall.

Or maybe I'll just solid tine them and fill the holes with sand as other have had success doing. It's still disruptive though and has many of the downsides of core aeration except obviously the need to remove the cores.

So if I do in fact decide to not aerate in the traditional way this spring I need to have a plan for if things don't work out. What if I'm totally wrong? When I am working in potentially hazardous areas in Search and Rescue we always like to have an escape route. We never want to commit to something 100%. As time goes on and new information become available we need to keep our options open to stay safe. So what if after skipping aeration this spring things don't work out. Well I can always go more aggressive in the fall. If I am not happy with the way the green perform this year I can double up in the fall. I can also needle tine more frequently through the season if needed. Last year during the extreme drought we only needle tined our greens twice. Even if I have to needle them 5x as much, it doesn't add up to significant labor compared to core aeration and has virtually no disruption on play.

Who knows?

Monday, 4 April 2016

"He's starving his greens"

This was a quiet comment I heard at a talk I did recently about my experience with the MLSN. This is something I hear a lot and a source of some confusion that I hope to clear up.
To apply this little fert safely you need to know what and when to apply it. It's all about timing.
A lot of people associate the MLSN with reducing fertilizer. This can be the case with nutrients that are in excess in the soil but my fertilizer reductions haven't been the result of using the MLSN entirely. If you are removing nutrients from the system you will eventually need to add those back in the form of fertilizer.

If you read closely on my blog you will learn that the huge reductions in fertilizer on my course have been the result of using soluble source fertilizers, halving my nitrogen rates all across my course, and simply withholding nutrients on my fairways as a Park Grass Experiment inspired experiment. The lack of fertilizer on my fw has nothing to do with the MLSN.

For the first year or two of using the MLSN I applied very little potassium but quickly had to bring the K back into my fertilizer applications as it is one of the nutrients used the most second only to nitrogen in the plant. It also leaches readily which is a big deal in a wet climate such as the one I'm in on the West Coast of Canada.

Yes the MLSN has helped me reduce or entirely eliminate the applications of calcium, phosphorus, and most micronutrients. This has saved me a few dollars here and there but I highly doubt that a significant portion of any fertilizer budget is for these nutrients. If it is I think you should take another look at your fertilizer inputs and needs on your course. By far the biggest fertilizer costs on any golf course will more than likely be nitrogen and potassium, both things that I apply to my greens and tees. The largest area of any course is probably the fairways so any reduction you can make there will have huge impacts on your fertilizer budget. As I said before, I'm only applying nitrogen to my fairways so the savings from the potassium I used to apply are huge.
Not bad for only nitrogen and wetting agents for inputs on fairways.

If anything the MLSN has taught me that we don't need as much fertilizer or nutrients as we used to think we needed. It has also helped me understand things such as the  park grass experiment. I have been purposely withholding potassium from my native soil fairways for 3 years now. We return the clippings so the losses of potassium from the soil should be minimal on these high CEC soils. I will be testing them this year to make sure.

The reason I'm doing this is to see what effect, if any, this will have on  weed populations on my fairways. We haven't used a herbicide on our fairways in at least 15 years and for the most part they are weed free. I guess that all depends on your definition of a weed but overall they are a visually appealing surface that is ideal for golfing on.

Some might see the low overall rate of nitrogen I have been applying to my course as "starving" my turfgrass. The reason I can safely go so low with my nitrogen rates is that I am using the growth potential formula as a guide to help me get into the ballpark for nitrogen rates and timing based on the average air temperatures each week or month. I then use my eyes to adjust based on growth rates and amount of play we are receiving (we have had our busiest winter ever and I've never applied less nitrogen through the winter and the greens have handled the traffic with no issues). The following table shows the average temps for each month and the very rough nitrogen rates I apply.
MonthAverage TemperatureGrowing PotentialN requirements (g/m²)
Total N requirements per year11.15

While I apply virtually no nitrogen for half the year, my grass doesn't require it as the air temperatures are too low for vigorous growth. Applying nitrogen during this time of the year only increases fusarium activity, money spent mowing, and thatch.
Fuzzy grass in the winter despite receiving no fertilizer applications 
Summer conditions
During the summer months I probably apply more nitrogen than most because the temperatures are ideal for cool season turfgrass growth. This increased nitrogen rates during the summer has helped me reduce moss and manage diseases like dollar spot and anthracnose without the need for pesticides.
Does this grass look starving?
It's all about timing. I used to apply nitrogen based on the theoretical ideal cool season growth curve but later discovered that cool season grass grows very differently based on the climate you are in. This is why I can apply much less fertilizer now than I used to. I only apply it if it is needed based on the temperature and what I am observing on the course. I used to apply the majority of my fertilizer in the Spring and Fall where I now apply the majority of my fertilizer in the Summer.

Not starving despite receiving only 2.25# N/1000 sq ft (12g N/m2) per season
I hope that people will continue to learn and read about the MLSN because it has the potential for some savings in fertilizer but I think the biggest advantage it has is that it will eliminate fertilizer applications that will make no difference to your turfgrass performance. This should theoretically help your operation be more sustainable and reduce the environmental impact that excessive fertilizer applications can have. If you want to find additional savings look into simple soluble source nutrients and the growth potential formula to fine tune your application timing and rates for your specific site. Happy MLSNing!