October 29, 2025 • 36 mins
We explore using precision agriculture to variable-rate apply residual herbicides using soil-driven maps to reduce crop injury on sensitive zones while maintaining strong weed control. Kyle Okke joins us to explain why OM, pH, and texture can set the rate and how sprayer mechanics affect success.
In this episode, we discuss
• Specialty crops that rely on pre-emerge residuals
• Resistant weeds driving need for fall residual applications
• Soil variability across landscape positions
• Reading labels and guidance on applications based on soil OM, pH and texture
• Diagnosing sunflower and pea herbicide injury patterns
• Pre- versus Post-herbicide application nuance and resistance risk
• Carrier volume (GPA: gallons per acre) as a rate knob
• Coverage demands for contact herbicides
• Sprayer pressure, droplets, and nozzle behavior
• When to split passes versus going across a field once
At GK Technology, we have a map and an app for that!
https://gktechinc.com/
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Sarah (00:00):
And now it's time for Ag Geek Speak with GK
Technology's, Sarah and Jodi.
Theme Song (00:10):
In the fields again.
I just can't wait to get in thefields again.
The life I love is writtenproduct for my friend.
And I can't wait to get in thefields again.
No, I can't wait to get in thefields again.
Sarah (00:31):
Welcome back to Ag Geek Speak.
We are so excited for thisweek's episode.
And we have a very specialguest who is now a recurring
guest of the show, uh, Mr.
Kyle Okke with Agile Agronomyout of Dickinson, North Dakota.
We're very happy to have youhere today, Kyle.
Kyle Okke (00:52):
Well, I'm really happy to be here.
Thanks for inviting me alongthe ride one more time.
Sarah (00:57):
One more time.
And we have a we have a reallyfun topic to visit about today.
So often when we're talkingabout precision agriculture
concepts and variable ratingdifferent products, we're
talking mostly about fertilizeror seed, those kinds of things.
But, you know, it feels to melike herbicides and pesticides
are kind of the last finalfrontier to really get that uh
(01:20):
precision concepts involved.
And Kyle has been working withhis independent crop consulting
business and his customers ondoing variable rate residual
herbicides.
So we're very excited aboutthis topic and and can't wait to
uh scratch the surface andvisit about it.
Kyle Okke (01:40):
Excellent.
Yeah, that's you know, lastfrontier is a fun way to say it.
I feel like there'll be morefrontiers and precision ag, but
this is definitely the one thatI think um it makes a ton of
sense why we're doing it.
I mean, just uh applyingdifferent rates of residual
(02:02):
herbicide that this this is alldriven off of not that it would
be cool to do or that we need toput a higher rate somewhere to
try to get more weed control.
It it's not around that.
It was more around that we haveall these sensitive crops to
particular herbicides that weneed to go.
(02:24):
Is there a way?
Well, we're we always governthe rate of certain things.
So western North Dakota,eastern Montana, well, all on
North Dakota, into Montana,anywhere that grows sunflowers,
anywhere that grows field peas,driedable beans, lentils,
chickpeas, even though I don'tthink chickpeas are really that
(02:44):
sensitive to a lot of theseherbicides.
But let's just say things thatfall in the pulse crop category,
soybeans would definitely fallin this one, I think.
But but those specialty crops,we don't have post-emergent
stellar options to use, so werely real heavily on a
pre-merge, and so it's like thatnecessary evil.
(03:05):
But everyone kind of out west,we govern our rates on we're
looking at every one of thoselike low organic matter, eroded
hillsides, and we go, I don'twant to lose all these
hillsides, even though those arelow-yielding areas, it just
drives you crazy.
Like, I don't want to do thatbecause the sure the herbicide
works really good, but then thecrop canopy is so compromised
(03:28):
that it ends up being a weedyspot later.
And it's like we got to dosomething different.
Sarah (03:34):
And okay, I want to back up for one second here and go
back to talking about the cropmix that you're talking about
where we where we place this,because I know a lot of your
perspective is from WesternNorth Dakota, and yet at the
same time, you know, this thisis a concept that I think based
on how we've talked about it,can really get applied in a lot
(03:54):
of different places.
So in eastern, oh yeah, ineastern North Dakota, I'm
thinking about dry beans.
Um, I think there could be someresidual herbicide things with
like Nortron or some of thatstuff, even in sugar beets and
you know, different differentthings like that too.
So it really is a specialtycrop thing, but even in
(04:15):
soybeans, I mean, what the waythat we're dealing with
resistant weeds right now, theseresidual herbicides have just
got to be such a big componentof our weed control system.
Otherwise, we we just leave toomuch on the table and and it
and it's we need these residualsto help us manage our resistant
weeds, I guess.
Kyle Okke (04:36):
Well, I'm I'm a western Minnesota native.
I was just visiting my parentsuh just the other week, and the
neighbor's field, right to myparents' yard, is is a great
example.
So uh where where I grew up isright on the edge of the Red
River Valley.
I guess we'd always called itthe Beetridge.
It's the Beach Ridge of GlacialLake Agassiz.
(04:59):
And so you get this mix of somebeautiful loams, and you have a
lot of these gravel and sandvanes that come up to the
surface.
And if you look on an aerialmap, or you just open your eyes
and look around, like from myparents' yard, if I look
directly to the north, there's ahuge drag line gravel pit that
they have there.
And then if I think of myschool bus route as a kid,
(05:21):
gravel pits lined all over theplace out there.
The property that my parentslive on is a reclaimed gravel
pit.
So kidding.
Yeah, so so you go from thislike absolutely beautiful, dark,
deep loam to just a pureskeletal sand all in the same
(05:43):
field.
And so you go from high organicmatter to no organic matter,
and you have like all thesegiant variances there, and so
yeah, soybeans, you know, youthink of stuff that's really
sensitive to yeah, low organicmatter.
Uh a lot of your group 14s, uh,your you know, like
metrobusans, stuff like that aregoing to be sensitive.
(06:05):
So, yeah, soybeans have anabsolute play in this too, in my
opinion.
Jodi (06:08):
So your your dad's a big gardener.
Does he garden on the sand too?
Kyle Okke (06:12):
Or is that outside of the most most of the most of
the sand soil types we have onon ours are um uh now just
planted to grass.
So they're just native, nativepasture.
Now we used to try to farmthat.
We'd irrigate that some, but uhit's actually a Galinden series
(06:33):
that uh of of it.
So it's a really nice that'sreally nice stuff.
It's a really nice soil thatthat they that he has his 10
acres of garden and he stilldoes.
Jodi (06:44):
Beautiful.
I I I just asked because I uh,you know, I think any of us that
work in agronomy now and havetaken some time to think about
differences in soils might well,I mean, I think all of us look
at our surroundings a lotdifferently now, right?
Like Hyo, you mentioned, youknow, the gravel pits that you
drove by when you were growingup.
(07:05):
Um, and now you understand thatthat's an artifact of of
glaciation in the glacial lake.
But I think that's all of us,right?
Like I think about where I grewup.
My mom gardened in a gardenthat after we she irrigated it
for so many years uh doingfarmers market, like it got
really cloudy, right?
We were introducing sodasodicity to the garden.
And that didn't, you know, hitme until later.
(07:27):
And I I bring that up becauselike that's this is what we're
talking about, these differencesthat we see and appreciate as
we are in fields longer or covera different area.
We start to see that everywherewe go, no matter if it's, you
know, a part of North Dakota oryou know, someplace like Indiana
or Illinois, these differencesare everywhere.
(07:47):
And not only do they have thepotential to affect just yield,
but other things that we applyto the soil too, like herbicide,
these factors that are in thesoil, these differences, that
affects how those herbicidesabsolutely.
Sarah (08:02):
And I think another thing that's changed over time and
agriculture, generally speaking,is you know, our equipment has
grown in size and we are farminglarger fields.
We've combined fields from thepast.
And so within that, we probablyhave, you know, the larger the
field size is, the moreopportunity there is to have
(08:22):
differences with the soilswithin that area.
And so it makes it very hardsometimes to have that flat rate
going over these large fields.
And I mean, you're from WesternNorth Dakota, Kyle.
So I'm sure that you see someof these larger fields all the
time out there.
Kyle Okke (08:40):
Oh gosh, yeah.
I there there's farmers I workwith that I've got fields as
small as uh 10 acres in size,and I've got fields as large as
uh the very largest field that Ido personally work with is like
1,640 acres or something likethat.
Sarah (08:57):
So that's a big field.
Kyle Okke (08:59):
And and that's and that's not a yeah, it is a very
big field, and it's not anoutlier.
There's actually multiplefields that are of that size.
I mean, they're just like yousaid, uh you know uh farming in
in a more arid region, you it'san economy of scale for a lot.
And and if you are fortunateenough to pick up either land
(09:22):
that you're renting that'sadjacent to other land you rent,
I mean, there's if you have acattle operation, keeping fence
rows and all that stuff makessense.
Sometimes landlords are goofyabout stuff like that, and they
like to keep their fence rowseven though they're completely
obsolete from keeping cattle in.
And that and that exists, butthen you have others that are
like, God, there's such an eyesort.
Like, we just like that cleanedup.
(09:43):
And and then they're like, hey,tear out the fence rows, and
that makes farming way moreefficient to have those fence
rows out of there, and fieldshave gotten bigger, and and
managing how you do things isvery different.
So a field that maybe had beenyou know, three different fields
in the past is one field now,and so that's that's where like
(10:04):
the variable rate anything hasmade absolutely a ton of sense
because when you have smallfields, you're kind of it the
the chance of that being all thesame soil type, all the same
parameters is a lot better.
The bigger it gets, you know,yeah, it it just the more
variability you start tointroduce, and and just going
(10:25):
into the flat rate anythingdoesn't necessarily make sense.
But yeah, that that's where itgets to like the the herbicides
and the weed control thing.
I'll preface this as you know,it it birthed out of seeing all
of your zone soil test results,and and so you get an idea like
(10:46):
for us out here, these were thegeneral trends, and it wasn't
like a standard, like thiswasn't a one-size-fits-all
trend, but you saw this trend alot, and you still see it a lot.
And the more you dig into itnow, like I can look at a soil
series map and a zone map, and Ican start to predict what I'm
gonna see now without seeing theresults.
Generally, our better landscapepositions have higher organic
(11:12):
matter, they have lower pH, andand then the textural class is
just whatever the textural classis, depending on the soil
series.
And then as you move up inlandscape positions, so here we
don't have a lot of pancake flatfields, we've got a lot of
rolling topography, and as yougo up in the landscape position,
(11:33):
you start to get some morecoarser ground because over time
it has eroded just because offarming, no matter how good we
are at our no-till practices,you have sloughing off of
organic matter and and topsoilmaterial, and you're closer to
the parent material, and so youhave coarser soil textures.
(11:54):
Um, also those areas becauseyou're closer to the parent
material, are a lot higher pH.
And there's this general trendof low organic matter, higher
pH, coarser soils in all ofthese high landscape positions.
And it's not like that on everysingle field everywhere, but
(12:14):
it's a pretty, pretty solidtrend in a lot of fields.
And then as you got into thethe really productive areas, the
organic matter reallyincreases, the pH really
decreases, and you generallyhave just a heavier soil
anyways.
And and so you you start tolook at like a label of a lot of
uh we'll just pick on Spartan,that's the name brand.
(12:36):
The name brand, Spartan, getsused on sunflowers and field
peas, chickpeas, driedable beansin some circumstances, flax,
safflower.
I mean it's like the specialtycrop residual herbicide,
pre-emergent residual herbicide.
(12:58):
And everyone will say, well,that's just Spartan when every
hilltop burns up after a rain,or you know, like everything
looks like it comes up decentinitially and then really starts
to pucker up and and get hurtlater.
And those labels have thisbeautiful roadmap built in it
(13:19):
already, and they they have thisflow chart, and it has the
parameters of soil textureclass, soil organic matter, and
soil pH, to tell you you knowwhat rate a herbicide is safe or
if you should even use it atall.
Sarah (13:35):
Huh.
Of course.
Maybe it's it's a place to likeshut it off, too.
Kyle Okke (13:42):
Yep, and and that's uh that's kind of a bridge that
I think I'll be crossing more asas time goes.
Oh, we've but that's that'swhere birthed the idea of just
like, well, ever everyone'slike, well, yeah, we should be
variable rating this, but it'slike, how do you make that work?
You know, everything's a tankmix, everything goes in one
(14:02):
tank.
But the practice has become wedo a lot of fall residuals now.
So now we're now we're startingto layer residuals to to try to
help, you know, kind of fill inall these gaps in time where
weeds can start, you know,coming through, and and so we're
just putting more armor outthere.
(14:23):
So what we started doing isjust running fall residuals and
then coming in and variablerating the entire tank mix, so
it'd just be like a glyphosateuh sulfentrazome tank mix.
And so you have to pick arather high rate of glyphosate
so that where you do lower yourrate, you're still achieving
(14:47):
control.
Uh but the good news is thatmost of the area where you're
reducing your rate when when wedo all this layered residual,
we're really just dealing withlike volunteer grains and small,
yeah, it's small grasses, easyto control stuff where the
residual herbicides are reallymore focused on broadleaf weeds.
(15:08):
And then, and then thenobviously you pick a rate of uh
of sulfentrazone to you knowmake this work across the field
where you're reducing and so thefocal point for us has been
reducing the rate low enough tominimize injury in those very
sensitive areas, and then justget to a full rate that that
(15:33):
gives us adequate weed controlin the areas that won't be
sensitive.
But potentially in the futurewe could be playing around with
you know increasing where weneed to have more, as long as
it's allowed.
But currently, right now, it'sjust it's just avoiding crop
injury in the areas that we getcrop injury because those end up
(15:54):
being point sources for weedslater when we injure the crop so
badly that you have like lateseason uh stink grass and and
some other broadleaf weeds likekosher does come in some of
those areas sometimes, eventhough you have a very effective
herbicide on it.
But you have no crop canopy toprotect it or to keep it from
coming.
Jodi (16:14):
Backing up a little bit, can you for somebody that's you
know, maybe they think, hey,maybe this is something that's
going on in my field, orsomebody that doesn't do
residuals in the fall, can youdescribe more about, you know,
what do these spots look like inthe field?
What are you looking for?
And what really confirms thatthis is a residual herbicide
(16:34):
issue when you see it?
And then maybe talk about whatthe standard rate and practice
was before, before you starteddoing your split residuals.
So start with symptomology andthen talk about what the the
common uh practice was before.
Kyle Okke (16:49):
So symptomology-wise, I think sunflowers are probably
the easiest one to pick onbecause they show it the most
showy, I guess, when you whenyou see self-enter zone injury
or group 14 injury.
So you'll every plant comes upnice.
And then it seems like once youget those first set of true
(17:10):
leaves out, if you have anoverload of that herbicide
because of soil parameters,because your soil organic matter
is really low, because your pHis really high, uh, and then if
your textural class, you know,it doesn't have like a lot of
buffering capacity.
So let's say you're on a sandsoil type, it it just gets this
(17:33):
uh the well the leaves justdecay, they just become
necrotic, and the whole plantstarts to stunt, I guess is the
best way to explain it, becausethe plant doesn't stop growing,
but it looks like it's startingto stack nodes on top of each
other.
So instead of like these nicelengthened inner nodes and you
(17:56):
get this this whole spread ofleaves, you you look at this
plant that you're like, wow,something definitely is wrong
with this plant.
It's not a nutrient deficiency,the because the whole plant is
it, it just it looks like it didget sprayed with something.
And and then the nodes stack upand the plants end up staying
relatively short in comparisonto all the uninjured plants
(18:17):
around it.
And and then it never reallycanopies, it never produces as
high of a yield as what maybe itpotentially could have.
Uh, field peas look verysimilar.
Uh field peas end up gettinglike these these necrotic leaf
margins, but then it's on thestems, it's in in the inner
nodes, but you'll see the innernodes stack really heavy on top
(18:42):
of each other.
So instead of getting this likenice length and stretched out
pea plant that gets some heightto it, it just is this little
stubby thing that never getsmuch height to it and and has a
bunch of just burnt leaf edgesand never really does much.
And it might put out a coupleflowers, but peas already aren't
(19:03):
a very proliferate growingplant to begin with.
So if you're you're stuntingthese plants and then they're
only growing a few inches tall,and they put on maybe one flower
and one pod, one will thecombine even pick that up.
Two, it never canopies theground.
And so the heat of the summerevaporates any moisture out of
(19:28):
that ground, you get morecapillary movement of water from
underneath that keeps drying itout and keeps drying it out,
and and so it just perpetuallybecomes a bigger issue over the
year.
But if we could just preventsome of that injury there, maybe
we can get just a little bitmore yield out of it.
There's never high expectationsout of those areas, but just to
(19:50):
have a crop canopy over it sowe can prevent really weeds from
taking over is a big deal.
Sarah (19:57):
Yeah, and I want to that's a great description of
how it changes over thelandscape.
And you know, that whole ideaof trying to avoid that injury.
And it's so interesting how youcan drive across a field on a
four-wheeler and all of a suddenyou drive into those spots and
and you're just you know you'rein that herbicide injury area
(20:20):
because you flat rated itacross, and there's no way to
manage that any better.
If you if you reduce the rate,those areas with that higher
organic matter and pH, you'rejust gonna get no weed control
at all.
So it's it's such a tough thingto make those decisions about
if you're flat rating this.
But I want to back up for asecond and talk about that tank
(20:43):
mix of, for example,sulfentrazone and glyphosate,
because essentially what you'redoing with this application is
you are both burning down post,you know, weeds that have
emerged with the glyphosate, andyou're also applying that
sulfentrazone, hopefully, um,you know, to get that residual
activity.
You know, I'm I'm sure it'sburning the weeds that are up
(21:06):
too and helping with theactivity of the glyphosate a
little bit, but primarily we'releaning on the glyphosate for
that post-weed activity and theself-intrazone is for a
residual.
And I think it's important forus to think about precision uh
herbicide applications inparticular from a different
perspective when we're talkingabout post-emerge weeds,
(21:29):
post-emerge applications versusyou know, pre- and residual
herbicide applications.
And I I think that's you know,because it's tough to reduce
those rates for thosepost-emerge herbicides.
We don't want to be creatingweed resistance out there.
So um, I don't know if you haveany thoughts on that or if
(21:50):
you've um you know thought aboutthat at all.
Kyle Okke (21:52):
Or that's that's the catch 22 of this whole thing.
That that's where uh, at leastfor us, what has made this more
successful is the use of fallresiduals so that the weed
spectrum we're dealing with, wecan overcome with the reduction
of the post-emergent herbicidethat's in the tank mix.
(22:13):
So that's that's a keycomponent of it.
If you are not applying a fallresidual, then it's wide open
what you could be dealing within in the spring.
And for us, the the big drivingweed, which it is for most of
North Dakota and into Montana,is kosher.
(22:34):
And and so you're really tryingto manage that.
If you have any of that comingup post or you know, that's
coming up and you and you haveto rely on your post spray,
we're gonna be in a lot oftrouble.
So that the idea is that we'retrying to eliminate the field of
majority or all of that, sothat it's never seeing the the
(22:55):
sunlight.
You know, it's never it's it'salways you know just a seed.
That's that's the idea behindit.
But yes, um there's could youknow that kind of a practice
give problems with other weedsif you're using reduced rates,
like say a glyphosate that wealready have resistance issues
(23:15):
and other weeds already?
So so yeah, you have to be verycognizant of that.
It's gonna be a field by fieldthing.
You definitely can't be justmaking blanket recommendations
and and running with it likethat either.
It it definitely takes uh well,it's it's this group we're
speaking with, you know.
(23:36):
Precision ag isn't a perfectcookie-cutter thing you can do
with every single field, right?
Like you can't just say, yeah,this farm farms 40 fields and
we're gonna just do the variablerate exactly the same for every
field.
It's like that's not true.
You're gonna pay specialattention to certain things on a
(23:56):
fertility basis and how you'regonna variable rate, and and you
go, yeah, maybe the cornseedpopulation we're gonna do
different on this field versusthis field.
You know, like this sand herehas has a very shallow clay
base, so it holds actually somedecent moisture and does really
well.
And we could put higherpopulations here, but this is
like sand with gravel, you know,subler underneath, and we we
(24:20):
won't grow any.
So, anyways, I'm just sayinglike so.
When it comes to the herbicidething, it takes it still takes
some of like the active fieldknowledge to go like, yeah, you
know what?
We were talking about doing thevariable rate thing all in one
tank mix.
No, no, you've got to go andmake, you know, if you want to
do this variable rate thing, youmight have to make two
different passes.
Sarah (24:41):
So there are are there fields that you have actually
done that where you haverecommended that um that second,
you know, to do a burn downapplication separately.
Kyle Okke (24:51):
So actually we we had a combo and it was um yeah, so
a lot of the sunflowers thisyear with one of my farms, that
that's exactly what we did.
So we had our we had our prepre like seeding burn down, and
we had a lot of broadleaf weedsalready coming, and and so we we
(25:14):
did come in with with a tankmix and and apply just for a
post-emersion circumstance totry to burn back all the
broadleaves that were there andthen seeded and then came back
and and did just a sulfenterzoneright right after seeding.
Jodi (25:36):
Let's dig into this a little bit more because like I
don't think it's as obvious whyit's more difficult to variable
rate herbicides than it is likea fertilizer, right?
Like we think of we talk aboutherbicide the variable rate
applications as being the finalfrontier because it is a little
bit more nuanced here, right?
Because as Sarah mentioned,there's the pre versus post
(25:56):
aspect.
And then also when we'reapplying herbicides, we're not
changing like you mentioned it alittle bit about how you're
adjusting your rates, Kyle.
But when we're applyingherbicides, we have to be
cognizant, at least if it's apost-emergent application, about
how many gallons per acreyou're applying.
And so if you reduce yourgallonage, you're reducing your
rate too.
But for post-emergence, GPA isvery important.
(26:20):
Whereas for residualherbicides, the GPA isn't as
important.
You mean gallons per acre?
Yeah, the gallons per acre forGPA.
So I think you were gettinginto that, Kyle.
But I just wanted to make thatclear for everybody, too, about
why it's a little bit morenuanced when we talk about
varying our rates of herbicides.
Kyle Okke (26:38):
There certainly is more nuance there.
Yeah, absolutely.
Yeah, you you couldn't uh wellhere here's a really good
example.
So say you're someone, and thishas become a lot more common
practice, that they like thetank mix sulfentrazone and
pericot together.
So the variable rating I'vebeen doing is via glyphosate,
(27:03):
and I'm very and and I didn'treally mention that before.
So we're variable rating theentire water volume.
So we're we're loading thesprayer for 10 gallon per acre
carrier volume.
Sarah (27:16):
So the rating your average carrier rate is about 10
gallons.
Kyle Okke (27:21):
Well, the average won't end up being 10 gallons,
but we're loading the field likewe're going out for a standard
static rate of 10 gallons.
So say we're we're loading forfive ounces of sulfatrazone, and
let's say we're putting out 32ounces of glyphosate, and then
whatever we do for our waterconditioner, and then we're
(27:44):
variable rate.
Sarah (27:45):
What's your carrier rate at that at 10 gallons at 10
gallons?
Kyle Okke (27:51):
At 10 gallons.
So you're loading the sprayer,assuming that you're gonna do 10
gallon spraying at thoseparticular rates.
And so if you were just tospray at 10 gallons flat, you
would you would get that rate.
And then what we've been doingis cutting back the water
volume.
So we'll go to five gallons ofapplied water volume over those
(28:15):
sensitive areas, which sure weget half of the particles out
there, but we also get half ofthe applied residual and half of
the it's half of the volume.
So it's so we're applying halfof the amount of herbicide over
those areas, and that's what'sreducing our injury because
(28:35):
we're not overloading the activeingredient, but that's also
where there's less glyphosategoing over those areas as well.
Sarah (28:42):
And so and if I can just add in at five gallons coverage
issues, you probably are gettingway less coverage.
Jodi (28:52):
Yep.
Kyle Okke (28:53):
And and in a in a no-canopy uh spring situation,
five gallons in glyphosate,that's fine.
We get decent coverage, we'vehad really good control.
But let's go to those groups offarms that have all of a sudden
started using periquat in placeof glyphosate.
(29:15):
Or there's some that even tryLiberty and do this.
Oh contact-only typeherbicides.
Now imagine if that's howyou're going to load your
sprayer and this is what you'regonna do.
If you were to go from 10gallons to five gallons, which I
would never advocate doing 10to start with as a standard rate
for those, but so you have toreally think specifically to
(29:39):
your tank mix.
So, yeah, to to both of yourpoints, it's very nuanced.
You you've gotta you can't makea blanket recommendation.
Sarah (29:48):
What you're saying then is that coverage component when
you're using like those contactherbicides like Pear Quat and
Liberty, it's so critical.
So if you're gonna startvariable rating based on the
carrier volume out there.
you're really going to impactbut how those uh those contact
herbicides perform.
Kyle Okke (30:07):
So this is this is the cool part in my opinion.
So this is I mean it it's takenyou know because there's a
there's like a lot of equipmenttech side of things that make
this possible.
So not every sprayer can evenjust because you have a rate
controller that can variably runyour pump doesn't mean that it
(30:31):
works with your sprayer or orfor veribrate spraying and so
I'll kind of like explain whatI'm meaning on this and then
I'll kind of roll into what I'mtalking about like in new tech
where there's there's way betterways to do this.
So it it starts with just theconventional sprayer.
And so the conventional sprayeris just saying you have a a
(30:56):
water tank, you have a pumphooked up to that tank and then
it's going out to the spray boomand and the whole spray boom is
going to see the same amount ofpressure applied to it through
that pump.
And you can have your variablerate controller that's that's in
your cab or that's controllingthe the flow through that pump
(31:16):
but in order for there to be avariable applied amount it's
going to be pushing morepressure or decreasing pressure
as you're going in and out ofthose booms through that pump.
And so because each nozzle is avery specific orifice size and
was designed to be run within acertain pressure range.
(31:38):
And so if you take aconventional sprayer and now
you're decreasing or increasingpressure anyone that runs a
sprayer goes yeah either youcollapse your pattern to where
it looks like raindrops comingout of the spray boom to
increase you know and everyonethat sprays sees this because
they get to a sensitive borderwhat is what's the first thing
(31:59):
to do lower the booms drop thepressure yep and and they're
being very careful because theless the pressure the less fines
that come out of those nozzlesand the less fines the less
drift and and so you're you'rereally lowering your you know
just you're making big drops notvery good coverage on those
(32:20):
areas now let's say you'respeeding up in the field well
that's but your rate control isalways compensating for things
so when you speed up in thefield it's increasing the
pressure running through thepump or it's increasing the
water volume going through thepump it's the same exact orphan
sizes on it's the same outputsize the same holes that are
coming out of the the spraynozzles so it has to it's a
(32:41):
higher pressure so it'spressurizing and then you're
running more water through thosewhich is going to make higher
pressure you know more poundsper square inch whatever coming
through each one of thosenozzles and that's going to
shear that water even more andthen this is where it takes that
that same droplet and then allof a sudden it explodes it into
(33:02):
tons of little fine droplets.
And so now if you started thatjust happens through the
variability of not being able tomaintain speed in a field.
So if you yeah and so thatthat's some of the challenges
that you were facing with aconventional sprayer when you
were doing this so yeah I welland and we didn't even attempt
(33:24):
it with a conventional sprayerjust knowing that knowledge but
even just a uh just goingthrough like a liquid system for
doing variable rate fertilizer.
So I've got like guys that doside dressing and or or running
liquid through their planter uhnot not starter but like like
I've got one one that has aconceal system from precision
(33:47):
planting for any applies all is28% that way.
So we have to so we we have toit they and then we do a lot of
top dressing uh too where wewhere we have to run as a
conventional system becausewe're just running such a sheer
volume through there.
For sure.
And so to maintain your targetyou to maintain your target rate
(34:12):
like with those huge hugevolumes of water going through
there they're they're slammingback on their hydro they're
they're really speeding updepending on the areas they're
in and so there's it's uh it'spretty taxing on on the operator
when they're trying to maintainlike target rates on that.
And so when it comes tospraying it's a way smaller
(34:32):
volume it'll keep up with it thepumps will but but what you're
seeing is a collapsed patternand then just pure fog coming
coming out of the back and andthere's a lot of implications
that come with that.
Sarah (34:47):
Those droplet changes are totally going to impact how the
the spray works especially onon weeds that are emerged but
it's still going to affect thecoverage on the ground and all
the rest.
Yeah we're gonna talk next timeon the next episode about how
we can work with the mechanicsof actually getting into making
(35:07):
the this right work we haven'teven talked about how to map
this out yet so we're gonna haveKyle back for a second episode
where we can talk about more ofthe mechanics behind this whole
concept of variable rateresidual herbicides.
So thank you for joining usKyle we can't wait to talk to
you next time and with that atGK Technology we have a map and
(35:32):
an app for that
And now it's time for Ag Geek Speak with GK
Technology's, Sarah and Jodi.
Theme Song (00:10):
In the fields again.
I just can't wait to get in thefields again.
The life I love is writtenproduct for my friend.
And I can't wait to get in thefields again.
No, I can't wait to get in thefields again.
Sarah (00:31):
Welcome back to Ag Geek Speak.
We are so excited for thisweek's episode.
And we have a very specialguest who is now a recurring
guest of the show, uh, Mr.
Kyle Okke with Agile Agronomyout of Dickinson, North Dakota.
We're very happy to have youhere today, Kyle.
Kyle Okke (00:52):
Well, I'm really happy to be here.
Thanks for inviting me alongthe ride one more time.
Sarah (00:57):
One more time.
And we have a we have a reallyfun topic to visit about today.
So often when we're talkingabout precision agriculture
concepts and variable ratingdifferent products, we're
talking mostly about fertilizeror seed, those kinds of things.
But, you know, it feels to melike herbicides and pesticides
are kind of the last finalfrontier to really get that uh
(01:20):
precision concepts involved.
And Kyle has been working withhis independent crop consulting
business and his customers ondoing variable rate residual
herbicides.
So we're very excited aboutthis topic and and can't wait to
uh scratch the surface andvisit about it.
Kyle Okke (01:40):
Excellent.
Yeah, that's you know, lastfrontier is a fun way to say it.
I feel like there'll be morefrontiers and precision ag, but
this is definitely the one thatI think um it makes a ton of
sense why we're doing it.
I mean, just uh applyingdifferent rates of residual
(02:02):
herbicide that this this is alldriven off of not that it would
be cool to do or that we need toput a higher rate somewhere to
try to get more weed control.
It it's not around that.
It was more around that we haveall these sensitive crops to
particular herbicides that weneed to go.
(02:24):
Is there a way?
Well, we're we always governthe rate of certain things.
So western North Dakota,eastern Montana, well, all on
North Dakota, into Montana,anywhere that grows sunflowers,
anywhere that grows field peas,driedable beans, lentils,
chickpeas, even though I don'tthink chickpeas are really that
(02:44):
sensitive to a lot of theseherbicides.
But let's just say things thatfall in the pulse crop category,
soybeans would definitely fallin this one, I think.
But but those specialty crops,we don't have post-emergent
stellar options to use, so werely real heavily on a
pre-merge, and so it's like thatnecessary evil.
(03:05):
But everyone kind of out west,we govern our rates on we're
looking at every one of thoselike low organic matter, eroded
hillsides, and we go, I don'twant to lose all these
hillsides, even though those arelow-yielding areas, it just
drives you crazy.
Like, I don't want to do thatbecause the sure the herbicide
works really good, but then thecrop canopy is so compromised
(03:28):
that it ends up being a weedyspot later.
And it's like we got to dosomething different.
Sarah (03:34):
And okay, I want to back up for one second here and go
back to talking about the cropmix that you're talking about
where we where we place this,because I know a lot of your
perspective is from WesternNorth Dakota, and yet at the
same time, you know, this thisis a concept that I think based
on how we've talked about it,can really get applied in a lot
(03:54):
of different places.
So in eastern, oh yeah, ineastern North Dakota, I'm
thinking about dry beans.
Um, I think there could be someresidual herbicide things with
like Nortron or some of thatstuff, even in sugar beets and
you know, different differentthings like that too.
So it really is a specialtycrop thing, but even in
(04:15):
soybeans, I mean, what the waythat we're dealing with
resistant weeds right now, theseresidual herbicides have just
got to be such a big componentof our weed control system.
Otherwise, we we just leave toomuch on the table and and it
and it's we need these residualsto help us manage our resistant
weeds, I guess.
Kyle Okke (04:36):
Well, I'm I'm a western Minnesota native.
I was just visiting my parentsuh just the other week, and the
neighbor's field, right to myparents' yard, is is a great
example.
So uh where where I grew up isright on the edge of the Red
River Valley.
I guess we'd always called itthe Beetridge.
It's the Beach Ridge of GlacialLake Agassiz.
(04:59):
And so you get this mix of somebeautiful loams, and you have a
lot of these gravel and sandvanes that come up to the
surface.
And if you look on an aerialmap, or you just open your eyes
and look around, like from myparents' yard, if I look
directly to the north, there's ahuge drag line gravel pit that
they have there.
And then if I think of myschool bus route as a kid,
(05:21):
gravel pits lined all over theplace out there.
The property that my parentslive on is a reclaimed gravel
pit.
So kidding.
Yeah, so so you go from thislike absolutely beautiful, dark,
deep loam to just a pureskeletal sand all in the same
(05:43):
field.
And so you go from high organicmatter to no organic matter,
and you have like all thesegiant variances there, and so
yeah, soybeans, you know, youthink of stuff that's really
sensitive to yeah, low organicmatter.
Uh a lot of your group 14s, uh,your you know, like
metrobusans, stuff like that aregoing to be sensitive.
(06:05):
So, yeah, soybeans have anabsolute play in this too, in my
opinion.
Jodi (06:08):
So your your dad's a big gardener.
Does he garden on the sand too?
Kyle Okke (06:12):
Or is that outside of the most most of the most of
the sand soil types we have onon ours are um uh now just
planted to grass.
So they're just native, nativepasture.
Now we used to try to farmthat.
We'd irrigate that some, but uhit's actually a Galinden series
(06:33):
that uh of of it.
So it's a really nice that'sreally nice stuff.
It's a really nice soil thatthat they that he has his 10
acres of garden and he stilldoes.
Jodi (06:44):
Beautiful.
I I I just asked because I uh,you know, I think any of us that
work in agronomy now and havetaken some time to think about
differences in soils might well,I mean, I think all of us look
at our surroundings a lotdifferently now, right?
Like Hyo, you mentioned, youknow, the gravel pits that you
drove by when you were growingup.
(07:05):
Um, and now you understand thatthat's an artifact of of
glaciation in the glacial lake.
But I think that's all of us,right?
Like I think about where I grewup.
My mom gardened in a gardenthat after we she irrigated it
for so many years uh doingfarmers market, like it got
really cloudy, right?
We were introducing sodasodicity to the garden.
And that didn't, you know, hitme until later.
(07:27):
And I I bring that up becauselike that's this is what we're
talking about, these differencesthat we see and appreciate as
we are in fields longer or covera different area.
We start to see that everywherewe go, no matter if it's, you
know, a part of North Dakota oryou know, someplace like Indiana
or Illinois, these differencesare everywhere.
(07:47):
And not only do they have thepotential to affect just yield,
but other things that we applyto the soil too, like herbicide,
these factors that are in thesoil, these differences, that
affects how those herbicidesabsolutely.
Sarah (08:02):
And I think another thing that's changed over time and
agriculture, generally speaking,is you know, our equipment has
grown in size and we are farminglarger fields.
We've combined fields from thepast.
And so within that, we probablyhave, you know, the larger the
field size is, the moreopportunity there is to have
(08:22):
differences with the soilswithin that area.
And so it makes it very hardsometimes to have that flat rate
going over these large fields.
And I mean, you're from WesternNorth Dakota, Kyle.
So I'm sure that you see someof these larger fields all the
time out there.
Kyle Okke (08:40):
Oh gosh, yeah.
I there there's farmers I workwith that I've got fields as
small as uh 10 acres in size,and I've got fields as large as
uh the very largest field that Ido personally work with is like
1,640 acres or something likethat.
Sarah (08:57):
So that's a big field.
Kyle Okke (08:59):
And and that's and that's not a yeah, it is a very
big field, and it's not anoutlier.
There's actually multiplefields that are of that size.
I mean, they're just like yousaid, uh you know uh farming in
in a more arid region, you it'san economy of scale for a lot.
And and if you are fortunateenough to pick up either land
(09:22):
that you're renting that'sadjacent to other land you rent,
I mean, there's if you have acattle operation, keeping fence
rows and all that stuff makessense.
Sometimes landlords are goofyabout stuff like that, and they
like to keep their fence rowseven though they're completely
obsolete from keeping cattle in.
And that and that exists, butthen you have others that are
like, God, there's such an eyesort.
Like, we just like that cleanedup.
(09:43):
And and then they're like, hey,tear out the fence rows, and
that makes farming way moreefficient to have those fence
rows out of there, and fieldshave gotten bigger, and and
managing how you do things isvery different.
So a field that maybe had beenyou know, three different fields
in the past is one field now,and so that's that's where like
(10:04):
the variable rate anything hasmade absolutely a ton of sense
because when you have smallfields, you're kind of it the
the chance of that being all thesame soil type, all the same
parameters is a lot better.
The bigger it gets, you know,yeah, it it just the more
variability you start tointroduce, and and just going
(10:25):
into the flat rate anythingdoesn't necessarily make sense.
But yeah, that that's where itgets to like the the herbicides
and the weed control thing.
I'll preface this as you know,it it birthed out of seeing all
of your zone soil test results,and and so you get an idea like
(10:46):
for us out here, these were thegeneral trends, and it wasn't
like a standard, like thiswasn't a one-size-fits-all
trend, but you saw this trend alot, and you still see it a lot.
And the more you dig into itnow, like I can look at a soil
series map and a zone map, and Ican start to predict what I'm
gonna see now without seeing theresults.
Generally, our better landscapepositions have higher organic
(11:12):
matter, they have lower pH, andand then the textural class is
just whatever the textural classis, depending on the soil
series.
And then as you move up inlandscape positions, so here we
don't have a lot of pancake flatfields, we've got a lot of
rolling topography, and as yougo up in the landscape position,
(11:33):
you start to get some morecoarser ground because over time
it has eroded just because offarming, no matter how good we
are at our no-till practices,you have sloughing off of
organic matter and and topsoilmaterial, and you're closer to
the parent material, and so youhave coarser soil textures.
(11:54):
Um, also those areas becauseyou're closer to the parent
material, are a lot higher pH.
And there's this general trendof low organic matter, higher
pH, coarser soils in all ofthese high landscape positions.
And it's not like that on everysingle field everywhere, but
(12:14):
it's a pretty, pretty solidtrend in a lot of fields.
And then as you got into thethe really productive areas, the
organic matter reallyincreases, the pH really
decreases, and you generallyhave just a heavier soil
anyways.
And and so you you start tolook at like a label of a lot of
uh we'll just pick on Spartan,that's the name brand.
(12:36):
The name brand, Spartan, getsused on sunflowers and field
peas, chickpeas, driedable beansin some circumstances, flax,
safflower.
I mean it's like the specialtycrop residual herbicide,
pre-emergent residual herbicide.
(12:58):
And everyone will say, well,that's just Spartan when every
hilltop burns up after a rain,or you know, like everything
looks like it comes up decentinitially and then really starts
to pucker up and and get hurtlater.
And those labels have thisbeautiful roadmap built in it
(13:19):
already, and they they have thisflow chart, and it has the
parameters of soil textureclass, soil organic matter, and
soil pH, to tell you you knowwhat rate a herbicide is safe or
if you should even use it atall.
Sarah (13:35):
Huh.
Of course.
Maybe it's it's a place to likeshut it off, too.
Kyle Okke (13:42):
Yep, and and that's uh that's kind of a bridge that
I think I'll be crossing more asas time goes.
Oh, we've but that's that'swhere birthed the idea of just
like, well, ever everyone'slike, well, yeah, we should be
variable rating this, but it'slike, how do you make that work?
You know, everything's a tankmix, everything goes in one
(14:02):
tank.
But the practice has become wedo a lot of fall residuals now.
So now we're now we're startingto layer residuals to to try to
help, you know, kind of fill inall these gaps in time where
weeds can start, you know,coming through, and and so we're
just putting more armor outthere.
(14:23):
So what we started doing isjust running fall residuals and
then coming in and variablerating the entire tank mix, so
it'd just be like a glyphosateuh sulfentrazome tank mix.
And so you have to pick arather high rate of glyphosate
so that where you do lower yourrate, you're still achieving
(14:47):
control.
Uh but the good news is thatmost of the area where you're
reducing your rate when when wedo all this layered residual,
we're really just dealing withlike volunteer grains and small,
yeah, it's small grasses, easyto control stuff where the
residual herbicides are reallymore focused on broadleaf weeds.
(15:08):
And then, and then thenobviously you pick a rate of uh
of sulfentrazone to you knowmake this work across the field
where you're reducing and so thefocal point for us has been
reducing the rate low enough tominimize injury in those very
sensitive areas, and then justget to a full rate that that
(15:33):
gives us adequate weed controlin the areas that won't be
sensitive.
But potentially in the futurewe could be playing around with
you know increasing where weneed to have more, as long as
it's allowed.
But currently, right now, it'sjust it's just avoiding crop
injury in the areas that we getcrop injury because those end up
(15:54):
being point sources for weedslater when we injure the crop so
badly that you have like lateseason uh stink grass and and
some other broadleaf weeds likekosher does come in some of
those areas sometimes, eventhough you have a very effective
herbicide on it.
But you have no crop canopy toprotect it or to keep it from
coming.
Jodi (16:14):
Backing up a little bit, can you for somebody that's you
know, maybe they think, hey,maybe this is something that's
going on in my field, orsomebody that doesn't do
residuals in the fall, can youdescribe more about, you know,
what do these spots look like inthe field?
What are you looking for?
And what really confirms thatthis is a residual herbicide
(16:34):
issue when you see it?
And then maybe talk about whatthe standard rate and practice
was before, before you starteddoing your split residuals.
So start with symptomology andthen talk about what the the
common uh practice was before.
Kyle Okke (16:49):
So symptomology-wise, I think sunflowers are probably
the easiest one to pick onbecause they show it the most
showy, I guess, when you whenyou see self-enter zone injury
or group 14 injury.
So you'll every plant comes upnice.
And then it seems like once youget those first set of true
(17:10):
leaves out, if you have anoverload of that herbicide
because of soil parameters,because your soil organic matter
is really low, because your pHis really high, uh, and then if
your textural class, you know,it doesn't have like a lot of
buffering capacity.
So let's say you're on a sandsoil type, it it just gets this
(17:33):
uh the well the leaves justdecay, they just become
necrotic, and the whole plantstarts to stunt, I guess is the
best way to explain it, becausethe plant doesn't stop growing,
but it looks like it's startingto stack nodes on top of each
other.
So instead of like these nicelengthened inner nodes and you
(17:56):
get this this whole spread ofleaves, you you look at this
plant that you're like, wow,something definitely is wrong
with this plant.
It's not a nutrient deficiency,the because the whole plant is
it, it just it looks like it didget sprayed with something.
And and then the nodes stack upand the plants end up staying
relatively short in comparisonto all the uninjured plants
(18:17):
around it.
And and then it never reallycanopies, it never produces as
high of a yield as what maybe itpotentially could have.
Uh, field peas look verysimilar.
Uh field peas end up gettinglike these these necrotic leaf
margins, but then it's on thestems, it's in in the inner
nodes, but you'll see the innernodes stack really heavy on top
(18:42):
of each other.
So instead of getting this likenice length and stretched out
pea plant that gets some heightto it, it just is this little
stubby thing that never getsmuch height to it and and has a
bunch of just burnt leaf edgesand never really does much.
And it might put out a coupleflowers, but peas already aren't
(19:03):
a very proliferate growingplant to begin with.
So if you're you're stuntingthese plants and then they're
only growing a few inches tall,and they put on maybe one flower
and one pod, one will thecombine even pick that up.
Two, it never canopies theground.
And so the heat of the summerevaporates any moisture out of
(19:28):
that ground, you get morecapillary movement of water from
underneath that keeps drying itout and keeps drying it out,
and and so it just perpetuallybecomes a bigger issue over the
year.
But if we could just preventsome of that injury there, maybe
we can get just a little bitmore yield out of it.
There's never high expectationsout of those areas, but just to
(19:50):
have a crop canopy over it sowe can prevent really weeds from
taking over is a big deal.
Sarah (19:57):
Yeah, and I want to that's a great description of
how it changes over thelandscape.
And you know, that whole ideaof trying to avoid that injury.
And it's so interesting how youcan drive across a field on a
four-wheeler and all of a suddenyou drive into those spots and
and you're just you know you'rein that herbicide injury area
(20:20):
because you flat rated itacross, and there's no way to
manage that any better.
If you if you reduce the rate,those areas with that higher
organic matter and pH, you'rejust gonna get no weed control
at all.
So it's it's such a tough thingto make those decisions about
if you're flat rating this.
But I want to back up for asecond and talk about that tank
(20:43):
mix of, for example,sulfentrazone and glyphosate,
because essentially what you'redoing with this application is
you are both burning down post,you know, weeds that have
emerged with the glyphosate, andyou're also applying that
sulfentrazone, hopefully, um,you know, to get that residual
activity.
You know, I'm I'm sure it'sburning the weeds that are up
(21:06):
too and helping with theactivity of the glyphosate a
little bit, but primarily we'releaning on the glyphosate for
that post-weed activity and theself-intrazone is for a
residual.
And I think it's important forus to think about precision uh
herbicide applications inparticular from a different
perspective when we're talkingabout post-emerge weeds,
(21:29):
post-emerge applications versusyou know, pre- and residual
herbicide applications.
And I I think that's you know,because it's tough to reduce
those rates for thosepost-emerge herbicides.
We don't want to be creatingweed resistance out there.
So um, I don't know if you haveany thoughts on that or if
(21:50):
you've um you know thought aboutthat at all.
Kyle Okke (21:52):
Or that's that's the catch 22 of this whole thing.
That that's where uh, at leastfor us, what has made this more
successful is the use of fallresiduals so that the weed
spectrum we're dealing with, wecan overcome with the reduction
of the post-emergent herbicidethat's in the tank mix.
(22:13):
So that's that's a keycomponent of it.
If you are not applying a fallresidual, then it's wide open
what you could be dealing within in the spring.
And for us, the the big drivingweed, which it is for most of
North Dakota and into Montana,is kosher.
(22:34):
And and so you're really tryingto manage that.
If you have any of that comingup post or you know, that's
coming up and you and you haveto rely on your post spray,
we're gonna be in a lot oftrouble.
So that the idea is that we'retrying to eliminate the field of
majority or all of that, sothat it's never seeing the the
(22:55):
sunlight.
You know, it's never it's it'salways you know just a seed.
That's that's the idea behindit.
But yes, um there's could youknow that kind of a practice
give problems with other weedsif you're using reduced rates,
like say a glyphosate that wealready have resistance issues
(23:15):
and other weeds already?
So so yeah, you have to be verycognizant of that.
It's gonna be a field by fieldthing.
You definitely can't be justmaking blanket recommendations
and and running with it likethat either.
It it definitely takes uh well,it's it's this group we're
speaking with, you know.
(23:36):
Precision ag isn't a perfectcookie-cutter thing you can do
with every single field, right?
Like you can't just say, yeah,this farm farms 40 fields and
we're gonna just do the variablerate exactly the same for every
field.
It's like that's not true.
You're gonna pay specialattention to certain things on a
(23:56):
fertility basis and how you'regonna variable rate, and and you
go, yeah, maybe the cornseedpopulation we're gonna do
different on this field versusthis field.
You know, like this sand herehas has a very shallow clay
base, so it holds actually somedecent moisture and does really
well.
And we could put higherpopulations here, but this is
like sand with gravel, you know,subler underneath, and we we
(24:20):
won't grow any.
So, anyways, I'm just sayinglike so.
When it comes to the herbicidething, it takes it still takes
some of like the active fieldknowledge to go like, yeah, you
know what?
We were talking about doing thevariable rate thing all in one
tank mix.
No, no, you've got to go andmake, you know, if you want to
do this variable rate thing, youmight have to make two
different passes.
Sarah (24:41):
So there are are there fields that you have actually
done that where you haverecommended that um that second,
you know, to do a burn downapplication separately.
Kyle Okke (24:51):
So actually we we had a combo and it was um yeah, so
a lot of the sunflowers thisyear with one of my farms, that
that's exactly what we did.
So we had our we had our prepre like seeding burn down, and
we had a lot of broadleaf weedsalready coming, and and so we we
(25:14):
did come in with with a tankmix and and apply just for a
post-emersion circumstance totry to burn back all the
broadleaves that were there andthen seeded and then came back
and and did just a sulfenterzoneright right after seeding.
Jodi (25:36):
Let's dig into this a little bit more because like I
don't think it's as obvious whyit's more difficult to variable
rate herbicides than it is likea fertilizer, right?
Like we think of we talk aboutherbicide the variable rate
applications as being the finalfrontier because it is a little
bit more nuanced here, right?
Because as Sarah mentioned,there's the pre versus post
(25:56):
aspect.
And then also when we'reapplying herbicides, we're not
changing like you mentioned it alittle bit about how you're
adjusting your rates, Kyle.
But when we're applyingherbicides, we have to be
cognizant, at least if it's apost-emergent application, about
how many gallons per acreyou're applying.
And so if you reduce yourgallonage, you're reducing your
rate too.
But for post-emergence, GPA isvery important.
(26:20):
Whereas for residualherbicides, the GPA isn't as
important.
You mean gallons per acre?
Yeah, the gallons per acre forGPA.
So I think you were gettinginto that, Kyle.
But I just wanted to make thatclear for everybody, too, about
why it's a little bit morenuanced when we talk about
varying our rates of herbicides.
Kyle Okke (26:38):
There certainly is more nuance there.
Yeah, absolutely.
Yeah, you you couldn't uh wellhere here's a really good
example.
So say you're someone, and thishas become a lot more common
practice, that they like thetank mix sulfentrazone and
pericot together.
So the variable rating I'vebeen doing is via glyphosate,
(27:03):
and I'm very and and I didn'treally mention that before.
So we're variable rating theentire water volume.
So we're we're loading thesprayer for 10 gallon per acre
carrier volume.
Sarah (27:16):
So the rating your average carrier rate is about 10
gallons.
Kyle Okke (27:21):
Well, the average won't end up being 10 gallons,
but we're loading the field likewe're going out for a standard
static rate of 10 gallons.
So say we're we're loading forfive ounces of sulfatrazone, and
let's say we're putting out 32ounces of glyphosate, and then
whatever we do for our waterconditioner, and then we're
(27:44):
variable rate.
Sarah (27:45):
What's your carrier rate at that at 10 gallons at 10
gallons?
Kyle Okke (27:51):
At 10 gallons.
So you're loading the sprayer,assuming that you're gonna do 10
gallon spraying at thoseparticular rates.
And so if you were just tospray at 10 gallons flat, you
would you would get that rate.
And then what we've been doingis cutting back the water
volume.
So we'll go to five gallons ofapplied water volume over those
(28:15):
sensitive areas, which sure weget half of the particles out
there, but we also get half ofthe applied residual and half of
the it's half of the volume.
So it's so we're applying halfof the amount of herbicide over
those areas, and that's what'sreducing our injury because
(28:35):
we're not overloading the activeingredient, but that's also
where there's less glyphosategoing over those areas as well.
Sarah (28:42):
And so and if I can just add in at five gallons coverage
issues, you probably are gettingway less coverage.
Jodi (28:52):
Yep.
Kyle Okke (28:53):
And and in a in a no-canopy uh spring situation,
five gallons in glyphosate,that's fine.
We get decent coverage, we'vehad really good control.
But let's go to those groups offarms that have all of a sudden
started using periquat in placeof glyphosate.
(29:15):
Or there's some that even tryLiberty and do this.
Oh contact-only typeherbicides.
Now imagine if that's howyou're going to load your
sprayer and this is what you'regonna do.
If you were to go from 10gallons to five gallons, which I
would never advocate doing 10to start with as a standard rate
for those, but so you have toreally think specifically to
(29:39):
your tank mix.
So, yeah, to to both of yourpoints, it's very nuanced.
You you've gotta you can't makea blanket recommendation.
Sarah (29:48):
What you're saying then is that coverage component when
you're using like those contactherbicides like Pear Quat and
Liberty, it's so critical.
So if you're gonna startvariable rating based on the
carrier volume out there.
you're really going to impactbut how those uh those contact
herbicides perform.
Kyle Okke (30:07):
So this is this is the cool part in my opinion.
So this is I mean it it's takenyou know because there's a
there's like a lot of equipmenttech side of things that make
this possible.
So not every sprayer can evenjust because you have a rate
controller that can variably runyour pump doesn't mean that it
(30:31):
works with your sprayer or orfor veribrate spraying and so
I'll kind of like explain whatI'm meaning on this and then
I'll kind of roll into what I'mtalking about like in new tech
where there's there's way betterways to do this.
So it it starts with just theconventional sprayer.
And so the conventional sprayeris just saying you have a a
(30:56):
water tank, you have a pumphooked up to that tank and then
it's going out to the spray boomand and the whole spray boom is
going to see the same amount ofpressure applied to it through
that pump.
And you can have your variablerate controller that's that's in
your cab or that's controllingthe the flow through that pump
(31:16):
but in order for there to be avariable applied amount it's
going to be pushing morepressure or decreasing pressure
as you're going in and out ofthose booms through that pump.
And so because each nozzle is avery specific orifice size and
was designed to be run within acertain pressure range.
(31:38):
And so if you take aconventional sprayer and now
you're decreasing or increasingpressure anyone that runs a
sprayer goes yeah either youcollapse your pattern to where
it looks like raindrops comingout of the spray boom to
increase you know and everyonethat sprays sees this because
they get to a sensitive borderwhat is what's the first thing
(31:59):
to do lower the booms drop thepressure yep and and they're
being very careful because theless the pressure the less fines
that come out of those nozzlesand the less fines the less
drift and and so you're you'rereally lowering your you know
just you're making big drops notvery good coverage on those
(32:20):
areas now let's say you'respeeding up in the field well
that's but your rate control isalways compensating for things
so when you speed up in thefield it's increasing the
pressure running through thepump or it's increasing the
water volume going through thepump it's the same exact orphan
sizes on it's the same outputsize the same holes that are
coming out of the the spraynozzles so it has to it's a
(32:41):
higher pressure so it'spressurizing and then you're
running more water through thosewhich is going to make higher
pressure you know more poundsper square inch whatever coming
through each one of thosenozzles and that's going to
shear that water even more andthen this is where it takes that
that same droplet and then allof a sudden it explodes it into
(33:02):
tons of little fine droplets.
And so now if you started thatjust happens through the
variability of not being able tomaintain speed in a field.
So if you yeah and so thatthat's some of the challenges
that you were facing with aconventional sprayer when you
were doing this so yeah I welland and we didn't even attempt
(33:24):
it with a conventional sprayerjust knowing that knowledge but
even just a uh just goingthrough like a liquid system for
doing variable rate fertilizer.
So I've got like guys that doside dressing and or or running
liquid through their planter uhnot not starter but like like
I've got one one that has aconceal system from precision
(33:47):
planting for any applies all is28% that way.
So we have to so we we have toit they and then we do a lot of
top dressing uh too where wewhere we have to run as a
conventional system becausewe're just running such a sheer
volume through there.
For sure.
And so to maintain your targetyou to maintain your target rate
(34:12):
like with those huge hugevolumes of water going through
there they're they're slammingback on their hydro they're
they're really speeding updepending on the areas they're
in and so there's it's uh it'spretty taxing on on the operator
when they're trying to maintainlike target rates on that.
And so when it comes tospraying it's a way smaller
(34:32):
volume it'll keep up with it thepumps will but but what you're
seeing is a collapsed patternand then just pure fog coming
coming out of the back and andthere's a lot of implications
that come with that.
Sarah (34:47):
Those droplet changes are totally going to impact how the
the spray works especially onon weeds that are emerged but
it's still going to affect thecoverage on the ground and all
the rest.
Yeah we're gonna talk next timeon the next episode about how
we can work with the mechanicsof actually getting into making
(35:07):
the this right work we haven'teven talked about how to map
this out yet so we're gonna haveKyle back for a second episode
where we can talk about more ofthe mechanics behind this whole
concept of variable rateresidual herbicides.
So thank you for joining usKyle we can't wait to talk to
you next time and with that atGK Technology we have a map and
(35:32):
an app for that
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