My name's Eric DeBoer and today I'm going to be discussing
my Ph.D. research here at the University of Arkansas under Dr.
Mike Richardson. And my research is focused on looking at the effects
of irrigating creeping bentgrass, a sand-based creeping bentgrass, putting green
with nanobubble, oxygenated irrigation water.
And so golf course superintendents are constantly concerned
with having an adequate supply of oxygen in the root zone of their putting
greens. Carrying out practices like
aerification, solid tine aerification,
sand top dressing to dilute organic matter and allow for
good channels of air flow and oxygen exchange in the soil.
But there is also another way that oxygen may be delivered to the soil,
and that can be through the use of oxygenated
irrigation water. And so rainfall
as it enters the soil, it contains dissolved oxygen.
The water contains dissolved oxygen that can be delivered to the soil
and used by plant roots and microorganisms in the soil.
And so we're trying to investigate the effects of adding
a large amount of dissolved oxygen to our irrigation water
and seeing its effects on creeping bentgrass,
root and shoot growth, soil oxygen
levels, organic matter content
and root morphology.
And so we have four treatments that we use — that we're looking at.
The first treatment is a irrigation pond water
that would be typical of an irrigation pond found on a golf course.
And then we're also looking at standard potable drinking water
from the Beaver Water District here in Northwest Arkansas.
And then both of those treatments, we use a nanobubble generator
and treat the pond water and the irrigation water
with high levels of dissolved oxygen through nanobubble technology.
And this is, that's a total of four treatments that we're looking at.
So we're here at the greenhouse to talk a little bit
about our materials and methods and how we're conducting this research.
So our nanobubble generator is inside of the greenhouse.
And we have this two hundred gallon tank that we transport
down to the irrigation pond to collect our irrigation
water and run it through the nano bubble generator.
And we use a transfer pump
to take the water from this tank
into the tank that we'll be seeing shortly
where we're circulating our nanobubble water.
So now we're inside the greenhouse where we are actually
treating our irrigation water.
And we have tanks of pure oxygen
and we have our nanobubble generator.
And then we have two large tanks used to hold
either potable water or our irrigation pond water.
And so we've gone down to the pond.
We've collected our irrigation pond water, and we've transferred it into our tank.
And this tank is used to hold the water
while we're cycling it through the nanobubble machine.
And the idea behind cycling the water is to saturate it
with as much oxygen as possible before using it to irrigate.
And so we, when we're going to generate our nanobubbles, we'll turn our oxygen on.
And we have our little irrigation system pump that
we use to take the water from the tank and cycle it through the machine.
So we'll flip this on.
Close our valve, and now our water
is running through the nanobubble generator.
And it's coming out here through this hose and cycling back into the tank,
and we're trying to saturate it with as much oxygen as possible.
So our irrigation water has been cycling
through the nanobubble machine, and we're ready to irrigate.
So we'll take our hose that is connected to the outlet
on the nanobubble machine, We'll remove it from our cycling tank,
bring it outside,
and fill up our tank
that we saw before that we use to irrigate our plots.
Our irrigation pond water untreated,
typically measures around five parts per million of dissolved oxygen.
After cycling it through
our nanobubble machine for around two hours, we're able
to elevate the dissolved oxygen to somewhere around 30 parts per million.
And this is dependent upon the water temperature,
the barometric pressure and also the salinity of the water.
So now we're ready to irrigate our plots.
We have a NorthStar sprayer here
with a seven gallon per minute pump
that we use to apply our treatments
to the the experimental area.
We fill the tank with twenty five gallons of water,
and we're replacing a known volume of water
based off of the evapotranspiration from the two previous days.
And so, now I'll see my volume of water
and I start irrigating my plot
as uniformly as possible.
And I have a known volume in the tank
that I'm monitoring
and watering the plot until that volume has been placed
onto each specific plot.
So I'll go back and check my water level
and continue to irrigate until the known
volume has been put on the plot.
In 2020, we did not detect any significant differences between treatments and root
growth as far as root volume, length
and diameter were concerned.
So in 2019,
of the soil oxygen content that we saw at a six
inch depth was about one kPa
higher for nanobubble oxygenated water
compared to the potable water treatment.
This result is inconsistent as in 2020,
we saw very inconsistent results with our oxygen levels
between the four different treatments
at a six inch depth. This summer of 2021,
we moved our soil oxygen sensors
about two inches higher in the soil profile to see if we're able
to detect any differences higher in the soil oxygen content.
But that data collection is still ongoing.
Moving to the clipping yields that we saw in 2020,
really there were no significant differences between any treatments
from the five clipping collections that we did.
And also looking at the soil organic matter content.
Again, no significant differences were detected in 2020,
And this data is continuing to be collected again this summer in 2021.
Nanobubbles remain an
effective way to quickly increase dissolved oxygen levels
in irrigation water, and definitely
can be used for treatment of irrigation ponds for algae removal.
So be looking for more nanobubble research in the future.
And thank you for watching.