Minnesota Golfer - Summer 2021 - 6

FRONT
Managing Expectations
G
olf course superintendents' jobs are dependent upon
the weather. If rain and shine are ample, balanced,
and timely, all is generally well for growing grass.
Geographic location is a factor, too, and knowing Minnesota's
unpredictable weather patterns (particularly during challenging
summer months) is important.
And now, there's an app for
that. The global DLI (daily light
integral) app, created by Dr. Micah
Woods at the Asian Turfgrass
Center, shows photosynthetically
active radiation (PAR), expressed
as DLI, for anywhere in the world.
Using satellite data from NASA
Power Agroclimatology to show a
summary of PAR (which provides
the energy for plants to grow),
the app tracks the amount of
daily light at any given longitude
and latitude over the past year(s),
which can greatly affect course
conditions.
* BY JOSEPH OBERLE *
A new daylight tracking app can assist superintendents and
inform golf travelers.
" The app may serve
[superintendents] as a way to
show golfers when peak times
of stress are occurring at their
favorite golf course. "
Click a map position in the app (for instance, at 47.6° N &
92.3° W, where Giants Ridge Golf & Ski Resort is located) and
you learn that for The Legend course, the maximum DLI of 62.3
last year occurred on June 13. To be sure, the DLI of southern
Minnesota courses was similar to those up north (for example,
Rochester CC at 44.0° & 92.5° experienced its max DLI of 60.8
on June 17, 2020) but the app drills down further to display
PAR averages over months, weeks and days (at five-minute
intervals) factoring in sunny and cloudy days.
Superintendents can track the data year-to-year and recognize
when to prepare for inputs, initiate mowing practices or
the highest stressed times for their courses (although superintendents
already know the trouble times for their light- and
temperature-dependent turf). The period of highest DLI in
Minnesota typically occurs during late-June through July, when
the highest ground temperatures combine with the longest sunlight
exposure to create the most stress on courses, and at a time
when they can become the busiest.
" The month of July is almost like managing what you know
6
is going to be some deterioration, " says Chris Tritabaugh, golf
course superintendent for Hazeltine National GC in Chaska.
" It's a balance between maintaining the condition the golfers
want and you knowing you're managing this deterioration. "
Superintendents are well-versed in local climate knowledge
and work to mitigate high stress
times, but the app may serve them
as a way to show golfers when peak
times of stress are occurring at their
favorite golf course and what they
might expect before coming to the
first tee.
" The grass may look green all
season to golfers, but from a turf
management standpoint, it's different
at each stage of the year, "
Tritabaugh says. " The knowledge
of what light's doing to the grass
would be interesting to golfers. The
things they experience and will colloquially
say regarding the turf-
such as 'the greens aren't as quick
in the spring'-there are physiological reasons for that and light
has a lot to do with it. "
The data bears out the notion that course conditions in
Minnesota are best in the fall, when ground temperatures are
still warm in August for healthy plants but daylight decreases
(and plant stress along with it). Hazeltine (at 44.8° N & 43.6°
W) experienced DLI averages under 30.0 last September-a
great time to hit the links.
Furthermore, the app may serve as a golf vacation planning
tool. Comparing DLI at Frances A. Gross GC in Minneapolis
(averages in the high 30s for April 2020) to The Raven Club
in Phoenix (DLI averages in the mid-50s last April) can help
you plan your annual snowbird departure. Or perhaps daylight
information for Bandon Dunes (where in March 2021, the
resort experienced an average DLI in the mid-30s) combined
with shoulder-season prices can offer the most bang for your
golf travel buck.
So, log onto asianturfgrass.shinyapps.io/global_dli/ and start
planning your next trip.
MINNESOTAGOLFER Summer 2021
mngolf.org
http://asianturfgrass.shinyapps.io/global_dli/ http://www.mngolf.org
Minnesota Golfer - Summer 2021

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