Thursday, 14 June 2018

Is Feast or Famine Better than Light and Frequent?

This is what I call "DiseaseyAF" weather
This past week I gave my greens a reasonably heavy fertilizer application (1g n/m^2 (0.25# N/1000) as all the signs I had were suggesting that my greens needed more fertilizer. The poa was thin and weak from just coming out of the seed head flush and was covered in anthracnose.

early signs of anthracnose this past week
I took this opportunity to spread some bentgrass seed as the competition in the next few weeks from the poa will not be very high and this is ideal for seedling establishment.

Not surprisingly, 2 days following the fertilizer application our growth rate skyrocketed and it appears that the anthracnose destruction has slowed which is what I wanted. I want thin, weak poa and the anthracnose is one of the best selective tools (available in Canada eh) I can think of to do that.

A few days following the fertilizer app they are looking much better despite still being covered in disease. F yeah!

While out changing pins today I noticed that the diseased poa was still relatively stunted and slow growing but the bentgrass was surging with growth. I thought that maybe this could be a better way to promote bentgrass over poa annua. Instead of light and frequent feeding we could restrict fertilizer until the poa starts to show signs of stress and disease, throw down some seed, then hit them with a relatively high dose of fertilizer with the hope that the stressed poa cannot take advantage of the increased nitrogen rates as the bentgrass can.

It's just a thought.

We can combine this with measuring the clipping yield and estimating the amount of nutrient removed from clipping removal and adjust our fertilizer rates throughout the year to account of nutrient release from organic matter. This way we can apply relatively high fertilizer rates at some times of the year but also burn organic matter at other times of the year.

While I love the idea of simply applying very little fertilizer like some successful bentgrass growers do. I also think that it might not just be about applying less, but applying the right amount at the right time especially when we take plant health and the desire to use less pesticides into account. From what I have seen and learned over the past few years, we can probably significantly reduce our need for corrective pesticides if we can simply (not that simple) grow the grass at the appropriate speed for the time of year.

My observations about disease and growth rate were reaffirmed this last week when the increased nitrogen rates resulted in an outbreak of fusarium. This was fully expected but also not a worry because the weather next week will be too hot and dry for fusarium to last long. The fusarium is also only present on the poa so any more selective poa death right now is welcome.

Still no fungicides applied since Jan 9 2018. 155 days and counting
It's also worth noting that disease has been so low on my greens that I have dropped phosphite from my disease management program. I have required a fungicide every spring but this year (and last) I made it through without despite applying less and less pest control products. Maybe it's the weather because we had one of the hottest and driest Mays on record.

small patches of fusarium mycelium were visible this morning on the poa. GOOD!

So I think the plan now for fertilizing greens will be to monitor growth rates and poa health and hold off on fertilizer applications long enough to stress the poa and then follow it with a healthy dose of nitrogen to fill in the voids hopefully with bentgrass. Ever since changing the rates and timing of nitrogen on my course (thanks to the growth potential formula) I have made huge gains in bentgrass on our greens. I wonder if taking this a step further by deliberately stressing the poa during the high growth months while also providing the bentgrass with enough nitrogen to remain competitive will be a viable strategy.

There is a lot of talk about how if you want to promote bentgrass over poa you need to use less nitrogen which I think it partially true but like all generalizations I think this idea can be improved upon. While less nitrogen is probably key, bentgrass isn't going to grow quickly enough to fill in the voids if we are trying to convert from poa to bent. Maybe if we can do a bit of both with this approach we will be able to get the advantages of both low fertilizer and high fertilizer rates to achieve our goals of having more bentgrass?

There's only one way to find out I guess.

This is, of course, subject to constant change.

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Monday, 11 June 2018

If I had a magic 8 ball

It would probably read,

"All signs point to fertilizing more!"


Despite my lack of a magic 8 ball I do have the next best thing. A HUD (Heads Up Display) which shows all my course data. This is supposed to help me make better decisions by automatically analyzing the data I collect and presenting it in a single place for my observation.

When I combine what the HUD is showing me with my disease observations it becomes clear what I should do and what I should do is fertilize my greens more. You might be thinking what's the big deal, just apply the fertilizer already you asshole! You are probably right but the reason I am so hesitant to apply fertilizer is that once you apply it, you can't take it back. As fertilizer has such a big impact on turf conditions and the costs associated with maintaining the golf course I need to be absolutely certain that the fertilizer is needed. So far this year we have mowed less than ever before. This has big impacts on fuel use, mower wear and tear and labor required to maintain the course. Growing the grass faster than absolutely necessary just wastes money.

1. Greens are lean

So far this year we have only applied 2.9 grams of nitrogen per square meter on our greens (0.64# N/1000). Through the measurement of our clipping volume I have been able to watch how much nutrients we are removing from our greens and compare that to how much we have applied.

In the last month we have removed more nutrients from our greens that we added. It's obvious from the chart below and it's also obvious with how visible the #friskyfairyring is on the greens. Bottom line, they are lean!

This fairy ring has never been visible on our greens. Bottom line, they are lean AF right now.
Wow, those greens sure are lean. Don't need a stupid graph to tell you that!

I know, I know, but having the data helps me understand how lean they are and why. In this case they are lean because we have applied less nutrient than we removed in the last month.

2. Disease

This week anthracnose showed up on our poa. For most of my greens there isn't much poa so I can let it die a quick and painful death. My first green is still mostly poa so I need to slow the death down to a level that will see the surface covered in turfgrass while the recently seeded bentgrass has a chance to fill in the gaps left behind by the disease and poa seed head.

anthracnose is back and by the looks of it, widespread

bentgrass seeded into the voids left behind from the poa seed head and anthracnose

The BMP guide from Rutgers suggests that increasing nitrogen rates will lessen the impacts of anthracnose among other things. My goal is not to eliminate the anthracnose but to slow its destructive tendencies down a bit. Anthracnose is a great selective pathogen that will kill out the poa and leave the bentgrass relatively unscathed.

So the increased nitrogen rates are double beneficial for dealing with anthracnose. They slow the disease down and hopefully help the bentgrass fill in the voids a bit quicker. I applied 1g of nitrogen per square meter to our first green which is the hardest hit with anthracnose for a cost of $2 this week. As time goes on I will continue to add these relatively heavy fertilizer apps to manage the anthracnose on this green and others as required.

Growing the grass at an increased rate in the summer is also a good strategy for dollar spot and is one of the principle strategies employed at the Vineyard Club. This week we had dollar spot show up on our greens and not surprisingly our growth rates are well below that where I have observed are good for managing dollar spot.

Dollar Spot is back. F sake
Growth rates are currently below the dollar spot target

There was a spike in disease pressure yesterday. The DS action threshold is probably set too high btw.
Despite the high disease pressure last month, the increased growth rates were enough to keep the disease away.
So there you have it. Growing the grass faster than we currently are will help reduce disease. Why don't I just apply a fungicide? Well a fungicide costs about $600+ where increasing fertilizer will cost maybe $10. It just doesn't make sense to run to a fungicide (yet) when I clearly have options that are much cheaper and probably (hopefully) just as effective.

3. Greens are too fast

Our green speeds are too fast which isn't a bad problem if you are a good golfer. Our course is difficult enough and as we approach the busy season where there are many novice golfers playing we need to keep our green speeds down to keep the time it takes per round down. No one likes a 5 hour round. Either way, we can stand to have them slow down a bit without worrying about them being too slow.

Greens speeds are the high. Note the dip in speeds during the effing poa seed head flush.

The sure are fast downhill these days

So there you go. This is just one example of how I am using my HUD and the data collection to make better decisions (hopefully) about how we grow our grass.

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