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Tru-Turf
RS48 Roller @ M.S.U. Field Day |
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| Topic: Lightweight
rolling not just for green speed |
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Mr Nikolai
is a turf grass academic specialist at Michigan State University.
He received his Turfgrass Certificate from Michigan State
University in 1986 and a Bachelor of Science in Crop &
Soil Science in 1992. He will be completing his doctoral degree
this spring, he also has ten (10) years experience in the
golf course business, four (4) of which were as a golf course
superintendent. |
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Welcome
to Orlando. I’m very happy to be here today and honoured
to share some things with you. |
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I spent
some time walking around the trade show and in doing so I
stopped by and looked at the green rolling literature. Amongst
some of the claims I found the green roller people saying
was that turf can handle high heat and dryness better if you
roll your greens and it also resists disease better if you
roll. I thought to myself if I hadn’t spent the last
eight (8) summers doing lightweight green rolling research
I wouldn’t believe any of these claims. I would think
“Yeah! Right” because I’m pretty sceptical
that way. But I am going to show you that indeed some of these
claims are true and we’ll see if we can make the pieces
of the puzzle fit together. |
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It was
around 100 years ago the debate about the frequency and weight
of rollers began to be debated. In 1901, Walter Travers wrote
the book “Practical Golf” and lightweight rolling
back then he thought you should roll daily with a light roller.
But exactly what was a light roller it really wasn’t
defined until 1906 when Horace Hutchinson, who was a greens
keeper said that a light weight roller should be 3 feet or
so in width and should weigh between a hundredweight and a
hundredweight and one half. A hundredweight is actually 112lbs
so it should weight between 112 and 168lbs. |
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Later,
Piper and Oakley got into the act – they were early
turf grass research pioneers and thought than, that frequent
rolling is better if you roll light rather than an occasional
heavy rolling. They pointed out that it was probably impossible
to roll too often on sandy soil. However, there were still
many people who thought that rolling did damage to the turf,
and somewhere in the mid-twenties research was conducted and
they began for the first time to understand that compacted
soil was bad for the turf, although no research with rollers
had been done. Although it was believed that rolling caused
compaction contrary to proof of that – so there was
this sort of assumption made and for that reason rolling kind
of disappeared for a while in the early part of the 20th century. |
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Now in
the late 1980’s – 1990’s because of the
requirement for extra green speed we began to see the lightweight
roller’s return once again, but there was again some
caution. Many superintendents reported there use for tournament
play only and should be restricted to maybe once a week. So
we went into these trials with a lot of caution, which is
probably a good way to do things such as this. |
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I’ve
done two main studies over an eight year period on greens
rollers and I’m also going to mention some research
that was done at Penn State University, in North Carolina,
to see how it all fits together, but for the main part I am
going to talk about a study I performed using three different
green construction methods and we will also look at their
physical properties. |
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The three
different soil construction methods are – the USGA standard
– which was an 85% sand 15% peat mixture. We also had
an 80% sand, 10% peat, 10% soil mixture and then a native
or push up sandy clay/loam soil. There are three applications
for each of these soil blocks. Each of the greens were 40’
x 40’ with a watering tower at the corner so that we
could control the irrigation. In 1995 I split these greens
basically in half to make it so I could roll one half of them
and the other half would not be rolled within the
same irrigation block, they all received the same moisture
which is going to be very important as we go along.
In 1997 the USGA decided to get involved and thankfully they
came and helped fund this study. |
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We also
put some nitrogen and potassium treatments on top of these
rolled and not rolled greens. I’m not going to go into
that very much today but it’s worth a mention because
you also see one or two of these slides will have nitrogen
data in them as well. |
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The roller
I used was an “O’lathe”. So that you know
I’m not doing any advertising they are now out of business.
It was 3 foot in length and weighed 940lbs, which by today’s
standards is a pretty heavy lightweight roller. I would imagine
one of the reasons it didn’t stick around was that the
transport method was slow and it was heavy. Today’s
models seem to be a bit quicker, lighter and easier to operate. |
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Very,
very, very, important. These plots were mowed early
in the morning, I spent 4 years working on a golf course,
so I’m used to getting up at the crack of dawn and I
would go in at sunrise mow the greens pretty much like I would
imagine most of you do and then within an hour after these
greens were mowed they would be rolled. Another very important
point is we rolled three times a week and another really important
point, we sand top dressed them bi/tri-weekly which means
every 2-3 weeks, depending upon the environmental conditions
and how fast the turf was growing. Another research done in
the 1990’s looked at roller frequency research. Green
speed was what we were looking at and the damage to the turf.
Penn State had plots rolled zero times, one and two times
a week and among their findings was that if you rolled at
these increments and frequencies you didn’t cause any
damage to the turf or any increase in compaction. |
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At Michigan
State the studies I performed zero to three times a week we
also found no increase in compaction. In North Carolina State,
zero and one times again, no increase in compaction, no decrease
in quality, but once you got up to four and seven times a
week at North Carolina State they began to notice that you
could see some decrease in turf quality and in one of the
two years of the study they saw an increase in the bulk density. |
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Another
thing we talk about is green speed, and we all agreed that
the day you roll the plots you increase the green speed 8%
- 16% and the day after what remains is a 3% - 8% increase
in that green speed. What this means in numbers is a 1 foot
increase the day you roll and 6” of that 1 foot remaining
the day after. Now exactly what that meant we wanted to do
some more studies and through the years I have done 3 or 4
different green speed perception studies at field days at
Michigan State University and we’ll look at some of
the data to see what that 1 foot or 6 inches remaining means
to us. For this study we had two different mowing heights
and basically the golfers were asked, is this green faster
or slower and we created greens that were 1 foot faster at
a 0.186 mowing height and created greens that were 1 foot
faster at 5/32” mowing height, we did it the same with
a 6 inch difference at those different heights and one of
the things I want you to note here is that the 6” difference
in green speed of both of these mowing heights 50% of the
golfers couldn’t, tell the difference, because if you
think about the question the question was “Which of
these two greens if faster?” 50% of them came up with
the 6 inch difference, 50% means you can’t tell. Now
once we got it to 1 foot in difference, golfers could tell
the difference and when we were at the mowing height of 0.186
over 80% could tell the increase in green speed. I like to
sometimes think of extremes. If I have a green that is stimping
at three and I compare it to one stimping at four, certainly
everyone is going to be able to tell the difference between
those two speeds, but if I have one that stimps at 20 and
the other one is stimping at 21, the chances of noticing that
1 foot difference diminishes. |
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Let’s
look at data from 1995 and 1996 from my plot and the way that
we rolled both years, we averaged a 1 foot increase on the
day we rolled, 30 hours after rolling or the next day we had
that 6” increase remaining. Now that’s a very
interesting number. Because if a golfer cannot tell the difference
of a 6” increase that means they cannot tell the difference
in a 6” decrease, doesn’t it? So I like to look
at this glass a being half full instead of half empty which
means that if a rolling frequency of three times a week can
allow us to have increased green speed over non-rolled greens
6 days a week. |
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Another
thing, I would really like to point out that 50 plus hours
after rolling you see about 4” difference. That’s
not very good. Now, we’ve dropped quite a bit of inches
off, so every other day or 3 times a week seems to be a nice
frequency and I really want to point out when you roll your
greens send your guys out there with the rollers, ensure they
roll after the mowers have cut the greens. If you stay on
a programme where the rollers keep beating the mowers you
are not going to get the increase in green speed that you
might desire. So it is actually pretty important that we mow
before we roll. |
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So as
I say three is the magic frequencies for us to find no increases
in bulk density, we’ve found no decrease in turf grass
quality and as I say we can increase the green speed six days
per week. |
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In 1994
Dr James Beard pointed out that we really need to look at
continual season long turf rolling because of the possibility
of increasing disease and I really would have thought that
sure dollar spot is one of those diseases most of us in this
room immediately think of Dollar Spot, how is it transported,
well basically mechanical means we’re told that we carry
it on our mowers, we carry it on our feet, we are carrying
it from location to location so we are helping spread it.
So it just makes sense that a roller would increase the amount
of dollar spot you would see. So in 1995 I started counting
the amount of Dollar Spot that I could find on each green.
The rolled greens was where I started to see less Dollar Spot.
Not at all what I was thinking I was going to see but this
is just one year, so the next year when the Dollar Spot started
to show up again, I did some more counts and lo and behold
every time I counted it in 1996 there was less Dollar Spot
where we rolled. This made no sense to me, sometimes this
is the kind of data that you don’t want to tell anybody
because like I said I am sceptical so I expect most every
other person is. So rolling three times a week was definitely
giving us less Dollar Spot. The green on the left is a not
rolled plot showing around 90% more Dollar Spot and the green
on the right that is rolled three times a week showing a huge
reduction in Dollar Spot. So why? Theories and that’s
the key word, theories why the rolling decreased the amount
of Dollar Spot. Why, it removes the dew? |
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You look
at those plots there, and maybe it's pretty easy to notice
that some have less dew than others. Now I'm going to point
out we mowed before we rolled and you also know that in the
morning sometimes you mow those plots and you can come back
a half-hour later and the dew's settled hence more moisture
again. Therefore a rolling removed the dew what fell afterwards.
Also it removes excess leaf litter. When you are mowing that
early in the morning, even though you have buckets sometimes
all of those clippings do not end up in the bucket, when you
roll the roller picks up some of those clippings and takes
them back to the wash pad. It could also decrease, the concentrations
of guttation water coming out of the leaf, turgid pressure
is high in the early morning when we are mowing first thing.
We cut the leaf, it allows the guttation to possibly extract
and that's a concentration very high in nutrients, the pathogens
can use them and that helps to spread disease because they
use that guttation water as a source. |
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What rolling
is doing at this time of the day is taking that guttation
water and spreading it out enough so that the concentration
is thin and isn't as high. It also increases the soil moisture
holding capacity. Now we said we never saw an increase in
bulk density and in fact over 5 years and two times a year
we looked at the physical properties on these plots we never
saw a change in the total porosity. However, we did see a
slight increase of more water holding capacity on the sandier
greens, so not always statistically significant but always
an increase or a trend as we would say in the amount of moisture
that the sandier soils held, no change in total porosity but
an increase in the amount of microspores, so more water holding
capacity. And interesting enough a lot of people would think,
when I was a superintendent, if I had Dollar Spot one of the
things I wanted do was put some nitrogen down, but as Clouch
& Bloomer reported some years back, low moisture is important
in the development of Dollar Spot maybe possibly more so than
nitrogen. |
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Remember,
I told you that we took these plots and we split them for
nitrogen differences over time so here we have these three
different soils and there are several things that I want you
to notice. Now, the box on the left from the USGA, I call
it the USGA green that the 85/15 mix, it has the most sand
or actually the least soil so the least water holding capacity.
Then as we move along we increase the amount of soil and we
are seeing that we have less Dollar Spot. OK, so in other
words, more moisture holding capacity. Now we notice if we
just look at the predominantly sandy green we have plots here,
the grey bar is not rolled and it has the low nitrogen content
and low and behold it had the most amount of Dollar Spot.
The not rolled high nitrogen we see has less Dollar Spot and
then after that we get to the rolled plot and we have a lot
less Dollar Spot. |
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As we
notice here that given the sandy soil it ends up acting more
like the native soil in the amount of diseases it gets. Now
this isn't a huge difference and this is just looking at the
sandy green and sand rolled is the blue bar the sand and not
rolled is the one underneath, we just see a slight increase
in the amount of water holding capacity so if we had an increase
in water holding capacity we might expect that we'd have less
localised Dry Spot and sure enough we do. The green on the
left was not rolled and the green on the right was but we
found that we had less localised Dry Spot where we we're rolling
and this is the data and we see that as we roll each plot
again we have less localised Dry Spot than not rolled. The
funny thing is Metcalfe, was a superintendent back in 1922
and he wrote for superintendents in the USGA greens directory
article - he named the article, "Treatments Kind to Unwatered
Greens" and one of his treatments was a way that stopped
him from getting localised Dry Spot, and that was to roll
the green. |
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When we
were working on the plot we began to notice that there were
bird peckings out there, so I thought I’d go out there
and count the amount of bird peckings that were on my green.
And I know you are thinking I am physco or something for doing
stuff like this but as a researcher we have got to go out
and count things so I went out and I counted these plots and
what I seemed to find was – where I rolled three times
a week I had less bird peckings than where they were not rolled.
Where I rolled three times a week in both of these instances
in 96 and 2000 there’s a reduction of 56%. Well who
cares? Well, lets make a connection. I counted those bird
peckings when cut worm damage was high in the golf courses
around us and what I found was that Dr Carter, a very highly
respected entomologist from Kentucky noticed that the cut
worms lay their eggs singularly on the tip of the blades of
grass and many of the eggs bypass through the mower blades
so his point was you have got to take the clippings far off
the green. Earlier I made a statement that I thought all those
clippings still don’t end up in the bucket and possibly
they end up on the roller the clippings that don’t make
the bucket or, in this case, the black cutworm eggs that are
on those clippings end up on the roller and back at the wash
pad, so we have less cut worm eggs on the green. |
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Also I
just wanted to point out one year, we did weed counts as well
and I had less broad leaf weeds where I rolled. The strange
connection about that is we can also see from this slide that
where I put down 1lb of nitrogen monthly as compared to 1/2lb
there were also less weeds. This is what we would expect less
weeds if we have more turf density, so the possibility could
be that we are actually having a little more turf density
when we are rolling three times a week and to fill that in
more, one year, 1996 was a very wet year up in East Lansing,
Michigan and as a condition of that, I got moss, so we went
out and we counted the amount of moss on each green and what
we did was I sent two workers out and they looked for anything
that was a dime size moss and counted it and what we ended
up with was that once again predominantly on the native soils
where we had the most moss but we found the not rolled had
far more moss than the rolled plots. |
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So my
gosh, I had better come up with a negative to rolling or no
one is going to believe me. So lo and behold, one year in
1996, where I rolled I had more microdopien patch than where
I did not roll. Now this also goes by another name, it is
“Pink Snow Mould”. I want you to notice the data
on that – 5th June there was a cold year – this
isn’t so much that I never observed the Pink Snow Mould
being increased coming out of the winter, but in any event
this is a negative. |
