Monday, 17 December 2012

Nitrogen Rates and Timing Comparison

With all my talk about nitrogen lately I thought it would be cool to compare how different methods of nitrogen fertilization would look. As nitrogen is one of the few things that if we add more the plant will use more the differences in application rates can have a varied affect on plant health and response. The following chart illustrates the same amount of nitrogen applied per season but at different rates at different times of the growing season.


Now we know that the blue line is what the plant actually needs so if the lines from the other application methods are above the blue line you are essentially over applying nitrogen and if the lines are below the blue line you are under applying. Over applying and under applying both have their purpose in turfgrass management but they also carry consequences.

I read somewhere that a visual turf response can be seen at nitrogen rates as high as 6Kg N/100m2 per season! Currently my rates are about 1.4Kg N/100m2 per season. So essentially I can see a difference if I applied 4.3X as much nitrogen as the GP model suggests for my climate. I can then use this data to compare the difference between the different fertilization strategies to see exactly how my turf is able to use the nitrogen I am applying. The following chart compares the different nitrogen use rates between the GP method and the constant rate method and also shows the difference in multiples of the required amount of N.

rates are in Kg N/100m2
So essentially I could expect to see a difference in growth response if I applied up to 4.3x as much N as was actually required by the plant. Looking at the column to the far right it shows that the constant method would be applying as much as 9.6X as much fertilizer as was required by the turf in March. It isn't until June that this method stops over applying nitrogen and in July and August I am applying half as much nitrogen as is required by the turf. No wonder I was getting hammered with disease!

What are the consequences of these practices? Applying more nitrogen than is required is wasteful and can't be good for the environment either. Under applying in the summer can only make your challenges more difficult.

This brings up another problem that I see with nitrogen fertility in the industry right now. With all of the different slow release nitrogen formulations how can you be assured that you are getting the release that is required. Each different product releases differently under different temperatures, soil moisture and particle sizes. Changes in the weather can really make a big difference in what you apply and what is made available to the plant, especially in the long term. For this reason I use soluble nitrogen sources exclusively on my putting surfaces. On my fairways I have a little more room for error as I do not use pesticides on them anyway. By using Urea and Ammonium Sulphate I am able to have a better idea of what is actually available to my plant and eliminate a lot of guesswork when it comes to how much nitrogen my plant has. When it comes to the importance of nitrogen fertility on plant health I cannot afford to guess!

Having the power and the knowledge to use nitrogen to our advantage is a great tool! We have the ability to apply a bit extra when needed to increase growth a bit or to recover from damage. We also have the power to reduce rates to slow the growth down which requires less mowing, less diesel and makes for faster firmer playing surfaces. What we need to know is how far off from what is required our nitrogen applications are and what the potential consequences may be. Is filling in those holes a few days quicker really worth the cost associated with an extra fungicide application? Financially and environmentally? Is that half pound N application really going to be usable by your turfgrass with the current temperatures?

I encourage everyone to compare their methods of nitrogen fertility to the growth potential model to see how far off of the plant's actual needs you are. Applying half as much nitrogen as is required surely has to have it's consequences. It's nice to be able to adjust the rates but it is important to keep the adjustments reasonable to avoid any negative consequences  It is the responsible thing to do for your bottom line and the environment.






Equipment Use Record: Using a form to keep data consistent

One of the very first spreadsheets I made on Google docs was my equipment use record. This spreadsheet keeps track of all equipment use on the golf course and allows me to filter the data so I can intensely scrutinize every detail.

The basis for this spreadsheet and pretty much all of my other spreadsheets is the form. The benefit of using a form is that it allows you to keep the data consistent and easy to input into the spreadsheet. Consistent data is extremely important when you decide to filter and sort it out later on. Even the slightest difference such as an extra space can keep the record from working.

The first step is to create a new spreadsheet in Google drive or docs and name it accordingly. I call my sheet "PHGC Equipment Records". I use this naming scheme for all my spreadsheets to keep things consistent.

Once you have done that the next step is to create a form. Goto: Tools--> Create a Form

Creating a form takes a little forethought and careful planning. This is the tool that is used to collect all the data and it needs to be thorough, well thought out and clear and easy to use.

My form starts with a drop down list for who is submitting the record. Drop down lists allow you to keep submissions the same and easy to input. To add a drop down list first select the "Add item" button on the top left of the edit form panel. Then select the "Choose from a list". You can then add all the names of those who will be operating equipment. I start with those who operate the most frequently to make it easier on them.

The next drop down list is which machine the record is for. I don't have very much equipment so I use the model names for this. A larger operation would probably find it easier to assign a number to each piece of equipment to keep is easier to work with.

Next is the hour meter input field. This is where the operator inputs the hour meter reading after they are finished their task on a piece of equipment. This is very important information when scheduling maintenance procedures like oil changes and setups and reel grinding.

Next is another drop down list for different areas of the course. I have it broken down into Greens, Tees, Fairways, Approaches, Rough, Traps and Cart Paths. You could have this broken down into all the areas that you have your course organized in. Some courses mow their green and tee surrounds with a different mower than their rough so I would add Green Surrounds to the list in this instance.

Next up in the form is a list of check boxes to indicate which holes the work was performed. This is especially important if you plan on doing efficiency studies with this data as all parts of the course are different sizes and take different amounts of time to complete. The first selection in my check boxes is "All". This makes it easy for the person filling out the form. I have made this question mandatory as it is possible to not select a box unless this is required.

I also have another drop down box for circle cut directions. I like to alternate directions of circle cuts to avoid laying down the turf. This information shows up on my website and shows the operator the last direction the circle cut was performed in.

You can add many other things to the form such as fuel quantity, amount of grass clippings collected etc. But for now this is basically all that is required.

formdata sheet with a bunch of data entries
Once you have your form more or less complete you can close the window and return to your spreadsheet. Remember that you can always go back to the edit form option to add any additional data. Now that you are back in the spreadsheet you will notice that the top row of the first sheet has the headers that you named in your form. When you submit an entry into the form it will appear here. It also includes a nifty time stamp which indicates the exact time the entry was submitted! This is handy as it automatically keeps the date for you which is a pain to manually enter. I always name the sheet where the form data is submitted "formdata" to keep it simple. I don't like spaces or capitals in sheet names as it makes referencing them in the future a bit harder. The formdata sheet should be left alone and you should never manually add any data to this sheet. This is the data in it's raw form and from where you will pull specific filtered data from. If you make an error in submission of the data in the form this is where you will edit it. Remember, only edit existing entries otherwise it can cause all sorts of problems!



Now comes the complicated part, filtering the data to make sense of it all! This is the part that really helps if you are a spreadsheet wiz but I will try and explain it as best as I can. I will provide links to official Google help articles when required.




The easiest way to filter the data is to create a sheet for each individual piece of equipment. I have created one sheet for all equipment but the filtering formula is rather complex. Here I'll show it to you so you can believe me!

=iferror(if(and(B1="All",B2="All",F1="All"),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2),if(and(B1="All",not(B2="All"),not(F1="All")),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!B2:B=B2,Formdata!E2:E=F1),if(and(B1="All",B2="All",not(F1="All")),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!E2:E=F1),if(and(B1="All",not(B2="All"),F1="All"),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!B2:B=B2),if(and(not(B1="All"),not(B2="All"),not(F1="All")),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!C2:C=B1,Formdata!B2:B=B2,Formdata!E2:E=F1),if(and(not(B1="All"),not(B2="All"),F1="All"),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!C2:C=B1,Formdata!B2:B=B2),if(and(not(B1="All"),B2="All",F1="All"),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!C2:C=B1),if(and(not(B1="All"),B2="All",not(F1="All")),filter(Formdata!A2:I,Formdata!A2:A>D1,Formdata!A2:A<D2,Formdata!C2:C=B1,Formdata!E2:E=F1))))))))))


The reason this is so complicated is because I have created drop down lists that include the option "all". This significantly adds to the work required to filter the data!


Yep, that is all required to filter all the data according to operator, date, machine, and area of the course! With this formula I can sort a specific operator on a specific machine mowing a specific area of the course during a specific time frame. It is really cool to compare different operators to see who is getting the best efficiencies and who needs some pointers for improvement.


The formula required for one specific machine is much simpler: =filter(Formdata!A2:I,Formdata!C2:C=$A$2,Formdata!A2:A>$B$1,Formdata!A2:A<=$D$1)


So what you need to do is create a new sheet and name it according to the specific machine you want to see the data from.
Filtered sheet for my 3100 greens mower.


I then put the name of the machine up top somewhere as well as the start date you want to filter and the end date. It is important to keep the name of the machine in this cell exactly as it appears in the "formdata" sheet. Often I will submit an entry with that machine and copy/paste the name into this cell to keep it identical. In the cell for the end date I put =today()+1 which keeps the date in this cell current plus one day so that you can see the current day's entries.


I then add the headings found in the "formdata" sheet just below the dates as can be seen in the above image.


To filter out the data for the specific machine I use the filter function. Enter this function directly below the date heading. Your source array should be formdata!A2:A. The "!" tells the spreadsheet that the formdata is a sheet name and not a formula name. This will set the source for the entire A column in your formdata sheet and will automatically expand as you add entries to the form. If you put formdata!A2:A99 it will stop filtering after 99 entries which is bad. When filtering from a formdata sheet always keep the second part of the array open without a row number.


Your first array condition should be to look for and filter only data for the specific machine you want. This will look like formdata!C2:C=$A$1. The C2:C should be whatever column in the "formdata" sheet that contains the names of the equipment and the $A$1 should be the cell in the filtered sheet which contains the name of the machine you want to find and filter. The "quot; is to keep this cell reference the same if you copy the formula to another cell which we will be doing later.


The next array condition should make sure that the entries are for only after the selected date above. this will look like formdata!A2:A>$B$1. This will search the column A in the "formdata" sheet for any dates that are higher (>) than the start date in cell "B1" on your filtered data sheet. B1 should equal whatever cell you chose to be the start date entry.


The next array condition is the end date which looks like formdata!A2:A<=$D$1. The "<=" means less than or equal to an the D1 references the cell where you current date is entered.


That's it for your first column in your filtered sheet. If you used your $ signs properly you should be able to copy this formula to the right and the sheet will filter for each respective column.


Now that you have your first sheet made go to "form-->go to live form" and your form will appear. Enter a submission for you latest filtered equipment sheet and one for another equipment sheet. Now go back you your newly created sheet and you should only see the data for the equipment that you want to see. Cool!


Now if you want to create another sheet for another piece of equipment you can simply select your sheet at the bottom of the page and then select "Duplicate." This will create another identical sheet to the one you just created. Rename this sheet to the piece of equipment you want it to be for and change the name of the equipment in the cell on the top left of the sheet (A1). Just like that and this sheet will be filtering the data for only that piece of equipment!.


You can do this for every piece of equipment you have in your fleet!


Now that you have the basic filtering down you can further edit each page to get more information. I like to add up the total hours that the machine is used but unlike most spreadsheets you have to do this at the top of the sheet rather than the bottom. This is because this sheet will continue to get bigger and bigger automatically as entries are added. I use the "min" and "max" functions for this task. In the cell above the hours input column enter the following =max(D4:D)-min(D4:D). What this does is search the column D for the maximum number then subtracts the minimum number from that column to give you the total hours of use for the specified time frame. The D4:D in this example should reflect whichever column you are trying to find the total hours from.


To make this form more accessible to my staff I have created a staff website that is only accessible to my staff Google account on Google Sites. I have then created a page on the webpage for each form. To add a form to your website in you spreadsheet select "form--->embed form in a webpage..." This will give you some HTML code. Don't be alarmed. Just right click on the code and select copy. Now when you are editing your website go into HTML edit mode and paste the code into the site. This will insert the form into your website and allow your crew to access the form easily on any device with internet access. I have all my forms loaded into my iphone through my website. It doesn't require any fancy apps or programs. Just your simple web browser. What I really like about Google drive, sites and everything else is it easily allows you to adjust who has access to what through their "sharing" options. Almost everything can have its access rights changed.


Congratulations! You now have the starting point for a very powerful data collection tool. I have taken this way further than I have just described but with this collected and sorted data you can now manipulate it any way you want! This is a bit more work to set up than the old fashioned paper forms but it will save you tons of time in the end!


If anyone has any questions about this process please feel free to leave a comment! I would appreciate feedback about things that I could explain more clearly in future posts on the subject.
























Friday, 14 December 2012

Nitrogen, the Overlooked nutrient in IPM?

Got some time? This one might take a while!

A very big part of any IPM program is turfgrass nutrition and arguably the biggest part of turfgrass nutrition is nitrogen. Since starting out in the turf industry I have always struggled with how much nitrogen I needed to apply to keep my turf healthy. What even is healthy turf?

Is this turf healthy?
For me healthy turf is a playing surface that requires the least amount of inputs and money to achieve the desired playing conditions. To achieve healthy turf I start with the basics and work towards the more complicated stuff. There's not much point in focusing on the details if you don't have the major things in check. Obviously the major things you need to grow healthy turf are air, water and sunlight. After these things comes soil fertility or turfgrass nutrition.

I have always felt that nitrogen was the biggest part of turf nutrition but I had no real way of easily knowing what the turf required. The other required plant nutrients were easier for me to work with as soil tests painted a pretty clear picture of what I had in my soils. Nitrogen on the other hand is a bit trickier to test for and I always struggled to know exactly how much nitrogen I should be applying to keep my turf "healthy." Nitrogen is one of those things that you can apply to your turf and see immediate results a day later. There isn't much else out there that give the immediate and obvious results that nitrogen does (maybe iron) so this was my main focus when trying to combat turf diseases the past few years.

There is a lot of data out there about nitrogen rates and their effects on plant disease. Fusarium, for example, is much more prevalent when more than 1.8kg of nitrogen is applied to 100m2 per season. This was a great starting point for my nitrogen fertility program as fusarium was the most destructive and prevalent turf disease on my course. This number was a great starting point but it really didn't help me much. How much and how often? How did I know how much my specific plants needed this week vs next week.

It wasn't until recently that I came across the GP (growth potential) nitrogen use calculations which made it easy to calculate how much nitrogen your turf needed based on the climate for your specific site. AT LAST! A straightforward way for me to determine my turf nitrogen needs. I switched over to this way of fertilizing this past summer. At first I based my rates on monthly average temperatures but in talking with Dr. Micah Woods from the Asian Turfgrass Center he urged me to base my calculations on the next week's forecast. I thought "why not?" and made the switch. After all it only added about 2 minutes of extra work for me to determine this over my previous methods. This was a way for me to really fine tune my nitrogen fertility rates. This is all great but how does this tie into my IPM program and how do I practically use nitrogen to control disease?

What I am thinking is this. If we look at the "disease triangle" we can easily see that in order for there to be infection there needs to be the pathogen, the susceptible host and the favorable conditions for infection. The pathogens are always there, deal with it. We don't always have control over the environments but we can monitor it and forecast disease threats. In my climate my disease threats are mainly fungal in the forms of Fusarium Patch, Dollar Spot, and now Yellow Patch. When you look into these disease and the cultural practices that offer the most impact nitrogen fertility often comes up. This makes sense as it is the nutrient that has the greatest affect on plant health. Generally Fusarium is most damaging under high N fertility, Dollar spot and Yellow patch are most damaging under low N fertility. The problem with the way I used to fertilize is that I was guessing what the plant needed and inadvertently making these disease issues worse by doing so.

I was always taught that cool season turf sees increased growth in the spring and fall and during the warm summer months it saw a decrease in growth rate due to the warm temperatures. Well this was very true if you were managing cool season turf in California! Turns out this growth rate model doesn't apply to everywhere because, you guessed it, not all sites are the same. So what research was telling me is that in the spring I was to apply higher rates of N to kick start growth and to match the supposed high growth rates. This was during a time when the temperatures were the most favorable for fusarium attack. So I'm applying lots of N when lots of N promotes the most prevalent disease? This doesn't make sense. But again I was going off of what I was taught and attempting to use nitrogen to produce a "healthy" turfgrass plant. At least my intentions were good.

Again my problems were worsened in the summer. Research told me that I was to reduce my N rates in the summer as the turf growth rates were slower and didn't require as much. Again, the most prevalent disease in the summer temperatures in my climate was dollar spot. I was dealing my turf a double whammy on this one. Deficient nitrogen applications and increased dollar spot activity! No wonder we got smoked every summer!

Look! I found some dollar spot! This was the extent of the damage
on my putting greens this summer!
This year I had zero dollar spot on my greens and I didn't require any traditional pesticides to control it. Of course you could give the credit to rolling, phosphites or Civitas but I think that there was more at play than simply these "bandaid" practices and products. Their mode of action requires already healthy plants and all they do is boost or trigger the disease response. In the end it is still the plant that is doing the work and if you have unhealthy turf these products won't do much for you. My nitrogen rates on my putting greens were roughly double those of previous years and I had zero incidence of dollar spot.  Whoa, wait! Double! well that equated to a cost of about $120 for N this summer apposed to about $1200 in corrective pesticide applications in previous years. The math here is simple. Next year I plan on significantly reducing my use of Civitas and phosphites as I don't think it was necessary to produce "healthy" turf this summer.

The fairways had a "little" dollar spot!
My fairways were a different story. They were completely smoked, no, NUKED with dollar spot this summer. This year I made the switch from regular SCU apps to two larger UMAXX apps timed to provide higher amounts of N in the Spring and Fall and less N in the Summer. As could be expected I was hammered with fusarium on my fairways this spring and hammered with dollar spot this summer. No surprises here. The damage was unlike anything I had ever seen....ever! Next year I will either do one big app in last spring/early summer or will add some N into my wetting agent spray apps for the summer. Not sure yet.

This fall I made plans to combat fusarium but none of those included anything to do with nitrogen. When I look back, the biggest difference to my maintenance practices this year was nitrogen rates. This year I had virtually no issues with fusarium patch. A traditional pesticide application was made in late September but my knock out trials showed that this was unnecessary. Ask any of the other superintendents around here and you will hear about the "Fall from hell" as far a fusarium  is concerned. Not here it wasn't.

An interesting aside here about disease and shade. This year I broke my putting green soil tests into sunny and shady greens. Not surprisingly the sunny greens had significantly less nutrients in the soil due to the higher plant metabolism. The shady greens tested at almost double the amount of nitrogen as the sunny greens. Could this be a contributing factor in the disease development? Not only did I have more fusarium in shady spots but I also noticed less yellow patch and dollar spot on the shady greens. Yellow patch and Dollar spot were always the worst on my most sunny putting surfaces! I would really like to see a study comparing plots in shade and full sun with the same rates of N applied to both or rates applied based on the specific growing environments of each site for disease pressure. Would there be a difference? My greens in the sun have been running lean on nitrogen and my greens in the shade have excess nitrogen. Nitrogen is one of those things that if you apply more the plant will use more (to a point) so I wonder if this is having any effect on the disease?
G1689 are the sunny greens. Cool huh! Highlighted are deficiencies according to MLSN! That's right I got a calcium deficiency hahaha.
Not yet realizing the role of nitrogen in IPM I cut off my nitrogen supply in late October even though the GP formula suggested that it was required. This was a mistake as this self imposed nitrogen deficiency gave the home field advantage to the yellow patch! CRAP!

My GP fertilizer calculator takes seconds to use
Next year I plan on pushing my nitrogen fertility program further. I am toying with the idea of tweaking the rates based on the current disease threat. Where normally I would be fertilizing at 100% based on the forecast temperatures I could change this percentage based on different temperature ranges. For fusarium I would maybe run at 80% N or with dollar spot maybe 110%. I'm not sure the specifics but it is definitely something I am going to be playing around with next season. This is another reason to use soluble source of nitrogen so you can constantly tweak it. Slow release n sources rely more heavily on outside influences for their release and therefore give you much less control over what the plant is actually getting.

A good analogy is a carb on an engine. The throttle determines how much gas enters the engine. The throttle is the temperature and the gas is the nitrogen. In turf we cannot control the throttle so we must supply the right amount of fuel or nitrogen. We can tweak the carb to either run rich on fuel or lean on fuel. Depending on the air pressure we need to adjust this setting. In the world of turf, air pressure represents disease pressure. As the disease pressure changes we need to adjust the amount of fuel ever so slightly to make sure that the engine performs accordingly for that specific condition. In turf, just like the engine, there is no point in adding more fuel than the engine can use. Doing so only makes the engine perform poorly. In this case more does not equal better. All too often I hear of turf manager giving a good heavy N application to get things growing quick. Sure this works to a point but if the temps aren't there you are wasting your time and probably creating a bigger problem with the lush succulent conditions. Fusarium outbreak following aeration and heavy N app sound familiar? Wouldn't it make sense to "harden" the plant leading up to aeration to reduce turf injury then increase N rates following all the wear and tear?  Maybe I'm wrong and I'm living in a fantasy world but this is how I am starting to see things.

I know a lot of you will laugh and dismiss my rantings as nonsense but the fact is that for the most part we are guessing how much n our turf needs and how much n we supply to our turf has a very big impact on all aspects of the plant health. By spending more time and effort getting the N rates just right I think that we will be able to produce better turf for less money with little to no pesticides. Of course there will be times when outside intervention is necessary. By focusing on more complex "issues" and completely ignoring something as "simple" and important as nitrogen fertility I think you are creating more problems than you are solving. Part of a good IPM program is making sound management decisions based on science and fact and reducing any guesswork there might be. Let me know what you think.



Wednesday, 12 December 2012

Record Keeping

It's that time of year again. Many of us use the slow winter months to look over our records to analyze this past season and plan for next season. In order for this to work it is important to have good meaningful data. Good data comes from good data collections which can sometimes be a challenge. In the next few weeks I plan on sharing my experience with using Google docs for all of my operations record keeping the past few years and will give step by step instruction on how to setup good meaningful records that will allow you to easily analyze all parts of your operation.

A few years back I was searching for a good record keeping solution. The old way of keeping records on paper had very little use to me as it was clumsy and very difficult to easily analyze the data. For me there is no point of collecting data if it cannot be manipulated to tell a story or paint a picture. I came across many companies that offered record keeping software and tried a number of them out for demo periods. The problem I had with these software packages was that they were very expensive, time consuming to set up, and were not flexible enough for me to make the best use out of them. I needed something that would be tailored specifically to my operation.

Finally I got a computer in the shop and spreadsheets opened a whole new way of keeping track of my records. Data sorting was much easier and I was able to make sense from all that collected data. For me there was still something lacking. With this system I wasn't able to record data directly into the spreadsheet in the field. Data input was also a hassle and I found it very cumbersome (especially when I was busy). Often data collection and input was put off or forgotten about......until I came across a product from Google called Google Docs or Drive. The reasons I chose this service over the many other available options was that it was free, worked on both macs and pc, was accessible from any computer or device with internet access, had most if not more of the features that Microsoft's Excel offered and had the backing of a large company so I was assured that it would continue to remain in service for a long time.

My equipment use record is one of my most valuable records
Basically Google docs is a cloud based system where you can edit spreadsheets  documents or anything else all on a central server that is accessed over the internet. No crazy networks or servers to deal with, just the internet. Added to the ease of use  was the ability to input data directly into a spreadsheet using a form that can be accessed over the net. The possibilities were endless and I immediately went to work.
Knowing exactly what and where was applied is extremely useful

Over the past few years I have made hundreds of spreadsheets for record keeping where a few have stood the test of time and really helped me improve my operations on the golf course.

Over the next few weeks I plan on sharing how I put together my equipment use log, equipment maintenance log, spray record and fertilizer record. I will start very simple and will work up to more advanced spreadsheet work.

If this sounds of any interest to you I urge you to create a Google drive account now and start messing around with what it has to offer your operation.

Thursday, 6 December 2012

Yellow Patch 2 weeks later

Well it has been almost two weeks since my last post about yellow patch. Initially I was panicking due to the many unknowns that I was facing. I had never seen yellow patch (R. cerealis) damage turfgrass. Shortly after publishing that blog post I was inundated with information about the disease from other superintendents. Apparently I'm not the only one out there having difficulty with this disease on my greens!

 7th green Yellow Patch Nov 24
7th green Yellow Patch Dec 06, same location as above picture.
A fellow superintendent suggested to me that I try a nitrogen application. I immediately went out and sprayed an application of Ammonium sulfate at 0.05kg N/100m2 or about 9kg for all my putting greens or about $8 worth of product. This was basically the accumulated nitrogen needs for the turf for the winter months according the the growth potential calculations for my climate. If this proves to be a practical and effective means of control for this disease that would be great as an application of a pesticide runs about $600.
6th Green Nov 24
 Looking back at my nitrogen applications the last application was made on October 24 at about .01kgN/100m2. I had then stopped any further applications as it got quite cold in early November. In retrospect I think I should have applied the heavy "dormant" nitrogen application in late october no matter what the growth rates were doing. Maybe this would have helped my situation. In past years I had always applied nitrogen through the winter months as our climate is quite mild. This year I had reduced N applications significantly to try and combat the fusarium patch which I have been surprisingly successful in doing. Since the N application I have not seen any fusarium show up anywhere (not even one single spot actually!).
6th Green Dec 04
At the time of our discussion and my blog post I had no pesticides in stock. I ordered some as I had no clue if the nitrogen applications would make any difference especially considering the time of year. Well it has been two weeks now and I haven't been able to apply any pesticides to the infected greens. At first it was a shipping error and then heavy rains. Now it is a lack of water to fill my sprayer! I was able to spray some Iprodione on two of my greens but not the ones infected with the yellow patch due to wind. In either case I am now glad that I wasn't able to spray this green.
Incubated infected turf plug. Seems to be recovering.

Two weeks later it seems that the turf is starting to make a recovery. It has helped that the temperatures have risen a little this past week (average temp of about 6C). I am not only seeing signs of recovery on the sunny greens but also the shaded areas. Of course it is still very early and the winter hasn't even officially begun yet. I don't think I would have seen the results I am seeing if the weather was cooler. I will continue to monitor the disease and can now apply something if the disease decides to get nasty! I anticipate that if the temperatures drop slightly I might again have a problem. I can only hope that temperatures drop enough that this disease becomes inactive! Here's hoping for a deep freeze!

Greens in full sun are still synthetic pesticide free 5 months later!





Saturday, 24 November 2012

Yellow Patch Attacks! Lesson Learned.

This summer I set out a disease management plan aimed at controlling Fusarium Patch with as little traditional pesticides as possible. So far this plan has been very successful at controlling M. nivale but in the past 2 weeks I have been caught off guard by another disease, R. cerealis or yellow patch or cool season brown patch or, or or or etc.
This is typically the worst that I have seen yellow patch in
previous years.
Historically R. cerealis or yellow patch has never been a disease of concern for me. Last year I wrote a post outlining how I have never had to do anything for this disease on my greens ever. Since writing that post I have learned a lot about disease management. While the message remains the same my experience has changed quite a lot. When I wrote that post I was still regularly using traditional pesticides as needed on my putting greens. I was using a lot less than in previous years but I was nowhere near the lack of pesticide use that I am at today. Since May I have sprayed 2 fungicide apps to my greens for fusarium, 3 greens have received no pesticides to date. I also did a small spot application last week to two of my greens for fusarium. This does not include regular Civitas and phosphite applications. It has been 2 months since my last traditional pesticide application.
The worst of the R. cerealis on my putting greens. Full shade.
I think the destruction caused by the R. cerealis to my putting greens has been so bad for two reasons. The first is the lack of pesticide use and the second is my fusarium management plan.

In previous years the rather regular application of broad spectrum fungicides probably provided a level of control for the R. cerealis even though my intended target was M. nivale. This is one of the problems with broad spectrum products and also one of the benefits. As the fusarium was much more prevalent and destructive than the yellow patch and also occurred under the same environmental conditions I never had a problem with the yellow patch. With the success of my cultural control and organic pesticide plan I am seeing yellow patch progress to a destructive phase that I have never seen before.

The second reason for this outbreak is my Fusarium Management Plan. The biggest flaw in this plan that I failed to account for any other disease that I might encounter. The reason I made this mistake is that I had never in 12 years ever encountered another fungal pathogen this time of year! This is something that I think a lot of other turf managers fail to realize about pesticide reduction. In the past, through the regular use of pesticides, we have covered up a lot of the lesser diseases while combating the ultra destructive ones. So while attempting to further reduce my pesticide use I have actually not made any difference this fall as other diseases that I didn't manage for popped up. My bad!

Disease symptoms are much less sever in areas with little to no shade.
Part of my fusarium plan was to limit nitrogen applications in the fall. In retrospect I may have gone a little too far this fall. Great results for fusarium, poor results for yellow patch. Literature suggests that lower nitrogen levels can increase the amount of yellow patch in turf. Nitrogen applications after the turf has stopped growing is often recommended. This suggests another benefit of dormant nitrogen applications, something that I have not yet done. Now that my turf has finally slowed down in growth (a month later than normal) I can apply some N and hopefully reduce the level of destruction come spring. We will see...

Next year I will have a better grasp on my thatch issues as well as this season I did not have any means of topdressing my greens which should reduce this disease a bit.

So lesson learned and I hope it won't end up being a tough lesson as the winter progresses. For the most part damage is not extremely widespread and a corrective fungicide application should hopefully help. As always I will be leaving some knock out trials for yellow patch to see just how bad this disease turns out to be. As it is winter having poor quality greens isn't a huge issue so it will be interesting to see how the untreated areas end up in the spring! So if you are attempting to reduce your pesticide use be sure to include any other potential threats in your plans even though they haven't historically been a problem! Don't just manage for your usual main pest. My hope is that others will learn from my mistake on this one.











Friday, 16 November 2012

Hello Mr. Newt!

Roughskin Newt Nov 15 9th green
 Yesterday while inspecting my greens I came across this Roughskin Newt (Tarichia granulosa). In recent months I have seen a noticeable increase in the number of newt or salamander sightings on the putting greens at my course. This is the fifth salamander sighting since September.

I have always made mental note of newt sightings on the course simply because they are quite rare. I can only remember about 4 or 5 sightings in 12 years before this September.

Salamanders are considered to be an indicator species as they are extremely sensitive to environmental changes or pollution. They basically breathe and drink through their skin. Where human skin is one of our greatest defense mechanisms, amphibians will absorb anything they come in contact with through their skin. Many also spend part of their life cycle in aquatic environments and terrestrial environments which means that any pollution in either will drastically affect them. They also aren't affected much by predators as they are extremely toxic if ingested. They give a really good indication of the ecosystem health as a whole! For more information on amphibians check out the BC Frogwatch Page .

Oct 28 Upper practice green.
Recently I have started to record any salamander or frog sightings and will be instructing my crew to notify me when they make the sightings as well. I have inserted a visual inspection of the greens before mowing or rolling into the employee procedure manual and have also added a cup inspection before replacing a plug in an old hole. I have found 2 of these guys in old holes. This data gives me a really good idea of the health of the environment on the golf course.

A hot topic among the course membership is the fact that we are required to leave any trees that we cut down in the bush. Most people see this as wasteful. These newts are exactly the reason why we are required to do this. Many salamander species live in old rotten logs and if we continually clean the forest around the golf course we essentially remove salamander habitat.

In the end the fact that I am seeing more and more sensitive species on the golf course only confirms that the decisions I have made over that past few years have been for the better. With all of the negative press about pesticide use lately it is hard not to feel that as a golf course superintendent that I am destroying the environment. Well you know what naysayers!? I am not and I have proof!



Thursday, 8 November 2012

Fall Disease Update--


The leaves are on the ground now so I guess it's safe to say fall has finally arrived. We saw a very extended summer that lasted well into October. The extreme dry conditions we faced in September were very interesting to say the least. I learned a great deal about both Fusarium and Dollar Spot and the conditions that favour these fungal organisms.

Early September saw the overnight temperatures finally start to drop down to reasonable levels. My original Fall disease management plan was put in jeopardy in early September due to a sprayer breakdown. I'm not sure if it was a coincidence or what but about a week after stopping my disease management program Fusarium started to show up on a few of my greens. It was in the usual spots at first but quickly spread out on all but 5 of our 12 greens. The greens where it wasn't located were the greens that received the most sun which wasn't surprising. The first signs of the fusarium showed up on the 5th of September but I was able to hold off a Fungicide spray until the 25th as the fusarium was very slow growing and not very aggressive. For the most part the turf was still able to outgrow the disease on my putting greens.

It's important to note that in my writing I am not considering Civitas as a fungicide even though it is registered as one. It doesn't act directly on the fungus but stimulates the plant's natural defence systems. I still apply it according to label rates and all that but the more I use the product the more I am starting to realize all the benefits it has to offer. I was putting Civitas down weekly at 1/4 label rates or about 0.125 ml Civitas/100m2.

Knock-out Trial
So on the 25th I applied Triton, a group 3 DMI to the affected greens at the label rate. In the past I had very poor success with this product and the product that I had in stock was leftover from a previous application the year before that had almost no impact at all on the Fusarium. What was interesting was that this product coupled with Civitas produced amazing results. A day after application there was no sign of mycelium where the day before the greens were fuzzy white! I was seeing curative results from a product that in the past I hadn't seen any results at all from. Of course there are other factors such as the weather, and the raise in HOC the week before but overall I was amazed.

I put down some knock out trials as usual to see how the untreated areas would manage. So far every untreated plot has fully recovered from any damage that might have occurred  All in all there was virtually no damage on any of the plots. You might ask why I applied the Triton in the first place then? Well when you see disease like the following picture on the entire green you cannot afford for it to get any more aggressive.



Today it has been 44 days since the Triton application and the disease level is still very low. Since that time I have put out 3 applications of Civitas.

Sept 30 Civitas @ .125ml/100m2
Oct 10 Civitas @ .250ml/100m2
Nov 5 Civitas @ .125ml/100m2

I have been experimenting with the timing of the Civitas applications a bit. I am applying it more on a growth potential model and less on a period of time model. Knowing exactly what kind of growth rates and vigour I can expect from the turf allows me to make better decisions about application rates and timing. In mid Oct we were experiencing very dry, and cool temperatures which brought the growth rates down significantly. For this reason I applied a heavier rate of Civitas but stretched the next application out as the turf really wasn't growing and I wasn't removing any of the product through mowing. In Oct I cut the greens 6 times where in the first week of Nov I have already had to cut the greens 4 times due to the warmer wetter conditions. The lighter application in early Nov was due to the fact that I am again mowing like a mad man and would more than likely have to apply another application in a few weeks.
Fuzzy white mycelium in Sept, my worst nightmare!

Rolling! Well my great intentions of rolling all through the winter stopped on Oct 12 due to the intense deluge of rain! Since that time the conditions have just been too wet to roll especially on some of our hillier holes. It was so wet in places that even my 4wd mowers couldn't mow. Now that the precipitation has slowed down a bit I will resume rolling regularly as conditions permit. So far this fall I haven't seen any significant difference in disease pressure on my trial green but for the most part disease pressure has been very low.

The crazy weather this fall taught me a few things about the two most important disease we face, Dollar spot and Fusarium. In the past people have always blamed Fusarium on the wet conditions. What I saw this September showed me that this wasn't necessarily the case, at least if you are concerned with rain. We saw the driest September in recorded history this year and sure enough as soon as the overnight temperatures started to dip below 10C fusarium showed up. What I learned is that Fusarium incidence is really more dependant on temperatures and less so on moisture. Of course standing moisture (dew) and excessively wet conditions don't help but my observations were that infection still occurred in the absence of rain.  It was especially bad in areas that were shaded (big surprise eh?).


Is he growing grass or Dollar spot?
Dollar spot was completely the opposite. I was always more concerned about the temperature than moisture with this disease. Turns out I was wrong again. The dollar spot severity in September was like nothing I had ever seen before, especially on fairways. We have a very difficult time keeping our fairways moist as we don't use any wetting agents and the areas that were the driest were the hardest hit. You could literally see the dollar spot from hundreds of yards away!
Compare treated and untreated

Yellow Patch! On the greens that didn't receive the Triton application in Sept the yellow patch has been crazy! I have always seen quite a bit of this disease but nothing like what I am seeing right now. These greens haven't received any traditional pesticides since May and it is really starting to show! I could be the first superintendent in history to actually worry about yellow patch!
Lots of yellow patch on greens that haven't been treated with traditional
fungicides.
It is really cool to see on the few greens that get the most sun how little disease there really is and it just reinforces to me the importance of providing full sun to the putting greens if you want to reduce your pesticide use. If all my greens had as much sun as my 6th green I could easily get by with Civitas alone with maybe one application of a traditional pesticide in the early spring. It is really too bad that trees have been included as part of the golf course design especially around the putting greens. It is really hard to convince everyone that they need to be removed. Sadly this is the best solution.

Here are a few videos I shot on Nov 08 around 11am showing the current disease conditions on my putting greens.

Hole 1:




Hole 3:


Hole 6:



Civitas and Dew

Recently there has been a lot of discussion about a new product in the Canadian turf industry, Civitas. Aside from all of the known benefits some superintendents (including myself) have noticed a slight reduction in dew on our greens.

In previous years we had always used a dew whip or drag on days where there was a heavy dew. We would either drag before the green mower or would only drag on days when we didn't cut the greens. This year I have yet to see the need to drag the dew off even once on my putting greens. This even 1 month post application at the 0.250ml/100m2 rate.

Areas that haven't been treated on my course have had a lot of dew compared to the greens. This is hard to compare, though, as longer turf tends to hold more dew naturally than the close cut putting green turf.

Early this week I applied 2 different Civitas rates to my fairway nursery to see if there was any difference in the dew formation. So far it appears to the naked eye that there is a difference but it's hard to tell if this is just related to the colour of the harmonizer dye playing a trick on the eye. I haven't figured out how I can quantify the amount of dew easily on these trial areas yet. My next application will be on one of my practice greens to compare.
0.125 Civitas on the left and .250 Civitas on the right. Nothing
in the middle.

Although I have a hunch that it is only an optical illusion I can say that there is much less, if any, rooster tails on golf balls when rolled on un-whipped greens. Perhaps this could be a better judge on how much dew is present. Who knows?

Aside from the playability benefit of having less dew on the greens this could be another reason why many other turf managers and myself are seeing such great results from Civitas. Less dew usually means less disease!

There is still dew present but I think it might be less
So for now it could just be that the dye is playing a trick on me but then again who knows. I really look forward to any formal research on this phenomenon.

Monday, 1 October 2012

The Rolling Fool, My Experience With "Extreme" Rolling

In the past year I rolled the putting greens at my course about 200 times. I'm not sure if this is some kind of record or not but what I do know is that nothing terrible happened contrary to most "expert" advice. I am often perplexed to the advice from so called experts warning of certain doom if you roll your putting surfaces more than 2 or 3 times a week. What I have to ask them is have they ever tried rolling daily, 2x daily? I have and take it from me, it won't kill all your grass if you do it right. In this post I will share my experience with rolling, the pros, the cons and what to watch out for, based on my practical hands on experience.
Equipment Log showing total number of recorded rolls in the last year in bold.

Firstly I would like to share why you would consider an "extreme" rolling regime. It will give you a uniform increase in green speed almost instantly without the need for lowering the height of cut. There are a million studies out there on this phenomenon. Rolling has allowed me to maintain consistent green speeds without having to mow every day. This has resulted in a huge savings of labour running and setting up my greens mower. It has also been proven to reduce and even prevent some fungal pathogens namely Dollar Spot. They can also prevent mower scalping by smoothing the putting surface. I have a few anecdotal observations to the disease and even weed reduction but they have yet to be proven by science so they should not be used as a reason to roll your greens yet.

The biggest affect rolling is going to have on your putting greens is compaction. Broad statements are often made that rolling leads to increased compaction and extra traffic stress. In a broad sense this is very true. Essentially what you are doing when you roll your greens is you are squishing down the leaf blades, the thatch layer and even the soil. Come to think of it every time a golfer steps foot, mower makes a pass, employee changes a pin you are compacting the soil and turf canopy. When you roll the putting greens you are essentially uniformly compacting the surface because that's what we want right? Uniformity. Now compaction can be a problem for putting greens so the key is to managing this compaction. It is important to note that the studies being conducted at Michigan State University have shown no significant increase in soil compaction on sand based putting greens that receive regular sand topdressings.

Essentially there are two types of rollers. Lightweight and Not lightweight. I classify lightweight rollers as anything with a ground pressure of less than 5 psi. This ground pressure is typically the same as a golfer walking across the green. Other rollers have much higher ground pressure and would therefore increase the rate of compaction. The theory behind lightweight rolling is to roll the green lightly with many rollers thus achieving the same smoothing effects as the heavyweight rollers without all that compaction.

Thinning caused from rolling when soils are saturated.
Personally I use a lightweight machine. It allows me the ability to roll as often as I please and has a lesser impact on soil compaction which is good. It also allows me to roll daily and not have to cut daily. Heavier machines compact the soil more and therefore can't be used as often. So why roll so much? Remember, I don't roll for green speed, I roll for disease reduction. I think that there are also some very beneficial uses for heavyweight rolling but they are purely speculative at this point. Here's a hint, moss.

Knowing your VMC can help you manage your soil
compaction.
Over the years there are a few things I have learned about managing compaction when you roll like a crazed maniac. The biggest detriment to turfgrass health and density has come from when we roll when the soils are saturated. The soil moisture levels are very important to know if you are rolling on a frequent basis. I have seen drastic density losses almost overnight simply from rolling when the soils were wet. How wet? Well that is something that will be different on every soil but for me if I get a VMC reading over 35 I will now not roll. This is where the art of greenkeeping comes into play and where you will have to learn from experience what is best for your site. Whoa, Whoa! Mr. Numbers is talking the art of greenkeeping? Ya, play around with it and watch your VMC. When I am able to maintain the moisture levels in my greens between 20-25% I haven't seen any loss of density due to rolling period. Another tool that is gaining popularity is needle tine aeration. This is a great way to reduce any negative compaction effects from rolling and is nothing but good for your turf.

Poa Toupee on 6x daily rolled plot.
I have heard of the Poa Toupee effect and just last week I got to witness it on my study green. Frequent rolling following aeration can cause the roots to shear off and not regrow. I saw this occur on my plot that was rolled 6x a day! Because of this it is probably a good idea to limit rolling following aeration especially when significant lifting of the turf surface occurred.

Skidding and wear caused from changing direction too
quickly on a self propelled lightweight roller.
Other negative impacts that rolling can have is wear from changing direction and careless operators. A lot of damage can be done very quickly if the operator isn't fully aware and trained on the machine. Self propelled lightweight rollers are really bad for this in my experience. Rolling following a heavy topdressing can make this issue even worse as the sand acts like tiny sharp ball bearings. To avoid this issue there are triplex mounted rollers that are much easier for the operators to use. The only drawback is that it requires another triplex mower which can be costly. Since the following picture was taken we have seen the approach return back to perfect health despite daily rolling. It's all about operator training and awareness.

So no, "extreme" rolling isn't all happy time and flowers like you might think I've made it out to be. There can be negative issues if rolling is done wrong just like all cultural practices. I hope that what I have learned over the years can help you avoid the mistakes I have made and have a very successful rolling program on your golf course.

These greens are still very much alive 200 rolls later!  Sept 17, 2012






Monday, 10 September 2012

Western Canada Growth Potential Comparison

My last post showed how the growth potential for cool season turfgrass in Western Canada was not at all like that that is commonly used. The common growth potential with peaks in spring and fall is more typical of areas like California. I have compiled the data for a number of areas in Western Canada to show what the growth potential for bentgrass looks like.




It turns out that the only place in BC or Alberta that really exhibits a slowdown in growth potential in the summer is Osoyoos. Naturally Osoyoos is the warmest and driest city in Canada.

I have always joked that Vancouver is "God's Country" and this graph just goes to prove that. Look at how long our maximum growth potential lasts. This part of the world is the perfect spot for growing cool season turf grasses.

Looking at the Banff growth potential you can see just how short of a growing season they really have. Edmonton and Calgary have longer growing seasons that Banff but they struggle to reach even 75% of the growth potential.

I have also graphed the recommended nitrogen application rates and timings for these cities based on the growth potential model.
Nitrogen rates based on a maximum nitrogen use rate of 3.5g N m2 for bentgrass.
This is pretty cool stuff. Theoretically turf managers in Edmonton could use half as much nitrogen than those in Vancouver. Even though Osoyoos has a much colder winter than Vancouver it still requires a greater nitrogen rate based on it's very warm and extended summer. A short distance north from Osoyoos in Kelowna and the nitrogen requirements are less than that of Vancouver. Interesting stuff.

Take a look at this data and compare it to what you are currently doing. I really look forward to any feedback from turf managers from Western Canada.

Sunday, 9 September 2012

How Much Nitrogen?

How do you decide how much nitrogen to apply and when? I have always used research showing the relationship between disease pressure and nitrogen rates as the basis for my fertility program. In general, nitrogen rates higher than 2kg/100m2 per growing season resulted in more fusarium. Fusarium is my number one pest so obviously I plan most of my agronomic practices around prevention of this fungal disease. Once I had the total rates I would basically just divide the total by the number of growing months I had in my climate or 8 giving me a number of around 0.25kgN/100m2 per month. I would then tweak these amounts based on the following growth model for cool season turf.
http://www.ipm.ucdavis.edu/TOOLS/TURF/ESTABLISH/seasongrth.html
For the most part this growth model is exactly how cool season turf performs in most cool season climates. The only problem is that being on the West Coast of Canada I maintain turf in an extreme range of this climate. My climate is extremely not extreme or temperate. It really doesn't get that cold in the winters and in the summers our average temperatures rarely rise over 20C. The only problem for me is that that previous growth model is based on colder winters and warmer summers than I experience in my location.

The West Coast of Canada 
is an extremely not extreme climate!

It wasn't until recently that I came across this article by Micah Woods Ph.D. (Asian Turfgrass Center) which shows how the Growth Potential equation, developed by the fine folks at PACE Turf, can be used for calculating nitrogen requirements based on your specific climate. To me this was ground-breaking stuff. I always knew that nitrogen rates should be based on growth rates but it was too hard to for me to figure that out.

The resulting data from this growth potential model was amazing. It turns out that in my climate the typical cool season growth model was completely wrong. On the coast we never really got temperatures high enough where the growth rates of cool season turfgrass slowed. In fact we barely reach the maximum growth potential for most cool season turf species in our climate. In our warmest month (August) we only reached 94% of the growth potential. It turns out that in my climate the growth rates more closely resemble those of warm season turfgrass. Cool!

Cool Season Turf Growth Potential for my climate
Dr. Micah Woods has been doing some really interesting research lately regarding turf selection based on climate as well as turf nutrition. I highly recommend checking out his blog for the latest and greatest information in the fields of turf nutrition and selection. Personally I feel that this kind of work is really forward thinking and important for the turf industry. For too long we have been forcing turf to grow where it's not best suited. Furthermore we have been creating a whole string of problems by not fully understanding turfgrass nutrition and soil science. Again, check out what he is doing, it is focused on warm season turf but it all applies to cool season turf as well. I have a hunch that he is going to post a lot of really cool data in the next few years. I can only hope and pray that he eventually does some cool season climate comparison work similar to the stuff he has already done for warm season turf (nudge nudge, wink wink).

Recently I was contacted by Micah, knowing that I closely monitor growth rates and have recently switched to the growth potential nitrogen model, who requested some of the growth rate data that I had been collecting over the last year. He wanted to compare growth rates with average temperatures and nitrogen application rates. The resulting chart clearly shows that the growth rate of my putting greens is more closely related to temperature and less so on nitrogen rates. Growth rate is measured in Baskets/day on my greens mower.
Data Compiled and Charted by Micah Woods Ph.D.

You can clearly see that in the Spring of this year I was applying a higher amount of nitrogen to my putting greens than August but the growth rates were still less than they were in August. It wasn't until June that I switched my nitrogen rates to the growth potential model. Even though my nitrogen rates dropped slightly you can see that growth rates continued to climb along with the average temperatures. I can't wait until next year to see how the data compares and the turf performs. I have a hunch that all three lines will be similar but who knows.

Recently I've had problems with equipment breakdowns and haven't been able to adequately fertilize my putting greens as can be seen at the end of this chart. Data collected over the next year will more clearly show the slowed growth rates this fall.

We also discussed the different ways that turf managers have historically applied nitrogen. Until recently I had basically applied nitrogen at a constant rate throughout the season. This is typically how most turf managers apply nitrogen. Sure we tweak here and there but for the most part it's not that different. This method can produce great conditions but is it the best way? The whole environmental movement recently has really focused on reducing inputs and only applying to the course what is actually needed. This growth potential model is an excellent tool for figuring out how much N your turf needs and avoids wasted applications. Remember, the amount of nitrogen that the plant is able to use is dependant on the temperature, not necessarily how much you throw on. It should be really interesting to see how this theoretical nitrogen use will apply in the real world over the next few years. Maybe higher nitrogen rates on the potential could be beneficial especially during spring green-up. Again time will tell. Again it's almost fall and I can't wait until next spring!

The following chart shows growth rates on my putting greens over the past 3 weeks. The soluble nitrogen applications are pretty obvious. At first we see a spike in growth but the growth rates quickly return back to normal a few days post application which is to be expected with 100% soluble nitrogen. Of course the magnitude of this growth spike can be managed by applying slow release fertilizers or soluble fertilizer in light and frequent applications like I do. This growth spike is one of the main reasons I use a 100% slow release nitrogen fertilizer on my fairways. I don't have the luxury to apply fertilizer light and frequent on my fairways. This 100% slow release virtually eliminates the growth surge following application.



Soluble nitrogen is often used for quick growth surges to recover from damage or cultural practices like verticutting and aeration. The above chart really makes this point clear with the quick growth surge often only one day post application. What is important to note is that after the quick surge of growth the typical growth rates resume based on temperature. I would really like to see data from putting greens maintained with partial slow release N and 100% slow release N.

Brainstorm time!

The main benefit that I see from using the growth potential model is producing a healthier plant. Since switching over to this fertilizing method I have seen a huge improvement in my turf health which can't be seen on any of the previous charts. Typically during the summer months I would reduce my nitrogen inputs as this is what I was taught to do. The only problem for me was that in my climate this is the wrong thing to do. Dollar spot is a big issue on putting greens in the summer and it can be successfully controlled with timely nitrogen applications. I have to say that a big part of my dollar spot control success this summer was due to the increased nitrogen rates. I also hypothesize that the reduced nitrogen rates in the spring and fall could have an effect on fusarium incidence.

Another benefit of using the growth potential model as well as monitoring actual growth rates is the ability to monitor the turf's ability to handle stress. Managing turf stress is key to reducing pesticide inputs and in producing good healthy turf. I can now easily see when my turf is able and not able to handle stress and I can change my maintenance practices to better suit this. There is no point in me applying a ton of nitrogen to help the turf fight disease if the turf doesn't even have the ability to effectively use it. Going into this fall I now have a really good idea of when I can use certain aspects of my fusarium management plan and when I will have to rely on other aspects.

Even another potential benefit of using this model is thatch reduction. By minimizing nitrogen inputs and matching them to their use potential there could be a reduction or no net gain of thatch. I really look forward to any research that is done on this topic in the future.

It has been a very enlightening year so far in regards to putting green fertility. Basically everything I leaned in college 8 years ago has been thrown out the window. I am now using the MLSN guidelines and have based nitrogen inputs on the growth potential for my climate. I have to say, this new way of doing things is working a lot better than the old way. I have cut my fertilizer budget by 60% and have drastically increased the quality and health of my putting surfaces. Almost all guesswork has been eliminated and I can make fertility decisions with confidence.

A big thank you to Micah Woods for coming up with the idea on how to use the data I had collected. When I first stated collecting growth rate data I had no idea how interesting and useful the results would be! I really look forward to his research on the subject.




And you thought I was kidding when I said I'd let the rough burn out.