Subscribe
Share
Share
Embed
Join the University of Minnesota Extension Crops team in addressing all your crop-related questions this growing season, from soil fertility, agronomics, pest management and more. We will tackle issues as they arise to help you make better crop management decisions this season.
Transcripts are auto-transcribed. If you need more accurate transcripts of an episode for ADA purposes, please contact Anthony Hanson - hans4022@umn.edu.
I'm Ryan Miller, crop
extension Educator
earlier this morning.
We recorded in an episode of
the Strategic Farming
Field Notes program.
Strategic Farming Field Notes is
a weekly program addressing
current crop production topics.
A live webinar is hosted at
08:00 A.M. on Wednesdays,
throughout the cropping season.
During the live webinar,
participants can
join in the discussion and
get questions answered.
An audio recording of
the live program is
released following the webinar
via podcast platforms.
Thanks and remember to tune
in weekly for discussion
on current cropping and
crop management topics.
Again, welcome again to
today's Strategic Farming
Field Notes program.
Happy you joined us today.
My name is List. I'm an
extension educator in crops.
I work out of the Worthington
Regional Extension Office
and we welcome Dr. Devlin
Sarang. Here's our extension.
We managed specialists with
UM Extension and also
Dr. Joe Eks extension.
We managed specialists with
North Dakota State University.
We also thank our
sponsors, Um extension,
and generous support from
the Minnesota Soban Research
and Promotion Council
and the Minnesota Corn Research
and Promotion Council.
With that, just a little crop
update that actually came out
yesterday due to the
memorial weekend holiday.
Corn's pretty much mostly
planted here in Minnesota.
93% planted soybeans,
86% planted.
I know that varies
across the state.
We've had some excessive
moisture areas,
we've also had some dry
conditions in some areas.
We've got some replanting,
a mix of all different things,
but we wanted to focus
today looking at cover
crop research and then
also how that ties in
with weed management
and any issues there.
First of all, I just
want to start with and
see Devlin and Joe.
If you guys could
just describe some of
the cover crop research
that you've been doing.
I know you've been
working with that from
the angle also of helping
us with what control?
Especially since we do have
so many issues with
herbicide resistant weeds.
Joe, why don't we
start with you first.
If you just want to take
a few minutes just
to describe some of
the cover crop
research that you've
been working with and give
us a little background on that.
Yeah.
For the most part we've
really been looking at
using rye course planted in
the fall and then terminated
at different times in
the spring primarily
for control of water.
Mp has been the goal
of our research
that's just continuing to
be a worse weed every year,
it seems, and we get new
resistance that pops up as well.
And knowing that
the herbicide options
are pretty limited,
seeing what else we can do
to help out rye is one of
those easier to adopt
management practices
on a large scale.
And so the last two
years what we had
done is looked at different
termination timings.
So either we'll just say
no cover crop or the absence
of rye completely or
terminated 14 days before
planting or planting green.
And in that case, we
planted and then terminated
rye either the same
day or the next day,
but after planting was the
important thing there.
Then we couple that with
the presence or absence of
a pre emergence herbicide.
We just happened to choose
fierce common pre mix of
a group 14, group 15.
And then what we did was within
each individual
management factors,
so rye management and then
absence or presence of a pre.
We waited until water Mp was
4 " tall in those plots
and then triggered
a post emergency
application and then
saw how the overall control
worked at the end of the year.
And the short answer
for water him
control is when we had
rye and a pre emergency
herbicide in the mix.
Those two things worked
pretty well together.
But when we did not have
the rye or we did
not have a Pre,
when we started to lose control,
certainly by the
end of the year.
And so look at
those two things as
complementing each other,
but certainly some folks
look towards hope of pay.
Can rye replace a pre
emergency herbicide?
And we have not seen
that in our research.
Interesting.
That's good. But you're seeing
a contribution at least
with the water hamp.
Even though water hamp is one of
those later emerging weeds too.
Yes. Yeah. Probably also
have to keep in mind
that everything
happens pretty quick here.
Once we get green up of rye.
It's usually here in Fargo
about the last week of
April, 1 week of May.
And then we have waterhemp
emerging about two or
three weeks after that.
A much shorter window up here,
which maybe helps out
with water management,
compared to maybe where Devlin's
at or where you guys
are at a little bit
further south where that
right greens up starts
accumulating biomass a little bit
earlier and maybe have
a month head start compared
to just a couple of weeks.
Yeah. Yeah. Devlin that ties in.
And Joe, we'll get back to some
more of your work too of course.
But Devlin, if you want
to just describe some
of the work that
you've been doing
across the state as well.
Yeah, what Joe is doing
up in North Dakota
that reflects our situation
in the northern
part of Minnesota,
North Dakota or
Red River Valley.
Whereas most of our cover
crop research is down south.
And we do in the eastern
western side of the state,
but in the southern part of
Minnesota, as Joe mentioned.
Actually, we're also looking
at the serial right,
like false serial right,
as a potential cover crop
candidates for Minnesota.
And the whole game
is the biomass.
Because if you have
enough biomass,
you'll get enough benefits
from the standpoint
of weed control,
from the standpoint of
soil erosion control
and everything.
It's all about the biomass.
How much biomass you can
get out of this cover
crop in the spring.
If you see the reports
by USDA back in
2017 when they did the
last cover crops survey,
Minnesota was one of
the bottom states regarding
the adoption of cover crops.
We had only 4% corn and seven
acreage under cover crop,
whereas in the
nationwide the increase
2012-2017 was 50% increase
and state like Maryland,
Pennsylvania, they had like 22,
35% area under cover crop.
And then if I compare
our Minnesota situation with
like other state as I mentioned,
like Maryland,
Pennsylvania, the reason is
like we have a unique
environmental conditions.
So as Joes, we have
really small planting window
between the harvest and the
first frost in the fall,
and also we have
unpredictable weather.
E.g. last fall was so dry in
Minnesota and North Dakota,
I know that there was barely
some emergence of cereal rye
that was planted last fall.
But again, in the spring
after snow melts,
we have just a couple of weeks
before we plant our
corn and soybean.
This is the main challenges
for adoption of cover
crop in Minnesota.
We are looking at different
management practices,
how we can, uh,
adapt the cereal rich cover
crop based in Minnesota.
Our research
components definitely
focusing on weed management,
but our treatments or
the comparisons we are
making are like different
cropping systems like corn,
corn system versus corn,
soybean system, including
silage corn, if that helps.
And also we have different
seeding rate for cereal rice.
We wanted to see, okay,
if we increase the seeding rate,
maybe 1.5 times,
or two times the
recommended seeding rate,
whether we can gain
the biomass quickly.
But we found that
was not the case.
Like if you have
60 pound per acre
cereal is seeding rate.
I think that's optimum
which is also
recommended by the sale.
And then we're also looking at
different termination
timing in the spring.
So if you delay your cover
crop termination by a week,
maybe by two weeks,
maybe by four weeks,
how much biomass
you can accumulate,
whether that helps with
the wheat control.
And so that we have different
termination timing,
different planting dates.
And we're like juggling
with a lot of factors.
And we're trying to
find out what are
the best recipe for cover
crops in Minnesota.
And we started this
research in 2020.
1.20 22 was our first year
when we get the data.
And what we found is 2022 was
a good year for cover crop
because 2021 fall was not
as much dry as 2022 fall.
This year will be
the second year for
our research and
we'll look into that,
like how much biomass we can
get this year out
of these studies.
Basically, we'll
have two years of
data to summarize by
the end of this season.
Very interesting. And
that's one thing you
bring up the biomass
question too.
Just curious because I've seen
the research where they're
talking about you need
to have like 4,000
8,000 pounds of
biomass per acre to actually
have an impact on
weed management.
What have you found
and what kind
of levels are you reaching?
Dublin. And then
I'm going to send
it over to you Joe too.
For the further northern
parts of the state here area.
Yeah. If I look into last
year's data, I mean,
when you planted early last
year also our spring was
wet 0 early planting was not
really early. It was like.
I would say like it
was like tenth of
May when we planted
our soybean and corn.
And that time we got about
1,000 pounds per
acre type thing.
It was not that much like as you
said like 4,000 No,
we didn't get it.
But still we saw with
1,000 pounds per acre,
like we got like some
weed control benefits
earlier in the season.
And then when we planted late,
which was end of May,
we got about 4,000 pounds
per acre and which
was really desirable because
those plots was pretty clean.
But, you know, sometimes if
you wait until end of May,
you may get yield penalty
from your cash crop.
That is the whole thing
we're studying like, okay,
what is the biomass
we're getting and
how much benefit we're getting
from that much biomass?
That's why we have
different planting dates,
different termination timing.
And as I said,
whatever the biomass you get,
that might be helpful.
But if you get really
little biomass,
like this year happened,
like I told you, last fall,
there was not much emergence.
And this year in the spring
with the early planning,
we didn't get much biomass.
We'll see how much
weed control we can
get out of that, Joe.
Yeah.
How about, how about you, Joe?
Because again, biomass, that
seems a really driving factor,
what we're getting from a
weed control contribution
and other potential
soil benefits too.
But what amounts are you seeing
and the impacts of
practices on how much
biomass is produce?
Yeah, I was just
looking this up here.
It looks like about three
to 4,000 pounds per acre,
is what we've been
getting here in
the Fargo area for our research
over the past couple of years.
That leads into, like I said,
it's not standalone
great practice
or replacement of a pre
emergency herbicide,
but that's about half of what
you're quoting there that
some other states really feel
comfortable with getting.
As far as biomass production for
complete wheat
suppression makes sense.
It's about a 50% control
measured in that case if
we're producing about
half the biomass
of some of those other studies.
Now, this year is a
little bit different,
certainly North Dakota and
Northwestern Minnesota.
A lot of the talk
this year has been
that we planted rye and
winter wheat for that matter,
into dry dirt, and just never
got emergence last fall.
And then finally,
when the snow melted,
we got emergence this spring.
And it's a question
of did we get the
vertilization requirements?
We actually bolt and
try to produce seed.
And here at least in Fargo,
it seems like we
did achieve that.
But we're not going to
get much for biomass.
And there's certainly
a carpet of
water hemp in the research
trial that I'm staring
at this year will
definitely be one of those
years where we're not
going to get a lot of
biomass production.
The overwintering
benefits that other
folks like for ancora soil
and preventing blowing.
That didn't happen.
But we're still going to
see what benefit we'll
get because we're shifting into
a new phase of our
cover crop research.
We are trying to delay
termination as late as possible
after soybean planting
primarily for weed
control but also for
potential yield loss from
rye due to soil usage.
That's always one thing
that we will run into
is the fact that
moisture is very
important and we'll get
these dry stretches and
we're in one right now.
A lot of people are too
where we don't want that ride
to use up too much water.
We're going to go
all the way to V
three soybean this year,
waiting to delay
termination until
V three soybean and see
when the sweet spot is for
getting weed control
without having that
rye use up too much moisture
to take away from soybean
yield at the end of the year.
This year might be a little
confounded by the low biomass.
The fact that the
rye didn't come
up until about a month ago,
but it will be repeated in
future years and hopefully
get back to that
4,000 pounds or so biomass
and see what the results are.
And then more typical setting
than the dry fall
without emergence.
Yeah, a lot of factors,
as you all know,
play a role in how much
biomass you get out there.
And what the take
is interesting,
it sounds like you're
looking at looking at
the V stage of soybeans for
when you terminate the cover.
Crap. What aspects
have you looked
at Dublin so far too
as far as one to
terminate the cover crop?
Because again, there's a lot of
different triggers
that you could
use as to one to do the course.
Also going to look
at the potential
yield impact on
our cash crop too.
Yeah, for the termination,
definitely, As I mentioned,
our main target is the biomass.
Then we also looked at
different termination option,
like what are the
termination option
you can have for
terminating cover crop?
Because we know that
chemical termination options
are the best because it works
fast, it's economic, but.
We saw that different
chemical group,
they work differently. E.g.
it is well known that
round up spraying,
round up is the best option
for terminating cereal,
right? Cover crop.
It really works fast.
In that case, within ten days
we have a field this year.
Within ten days, everything
is yellow and brown
and you're ready to plant
even some options
like Cleo edam.
They're slow. We select
max type product,
they're really slow,
and it takes three weeks
to get it yellow and
it's not totally yellow,
it's really slow.
We have options when you
have like glyphosate type,
like Liberty type product,
it is not 100% kill.
We have to pick those
herbicide options carefully.
And also we checked some
termination option for
the organic grower because we
thought like some of
our organic growers,
they're interested to use
the cereal rye cover.
If they have the roller crimper,
that is good idea
because they can
roller cereal rye and can
start planting something.
But we know from
the literature that roller
crimper is not also
100% kill for the cover crop
and it's also stage specific.
We tested some of the
non herbicide options
for the termination of
cover crop and different
stage of the cereal rye.
And we found that if
you were like cutting
the cover crop for any kind
of like feed purpose
or you're doing
gradging or something.
Doing it early in
the tailoring stage
is not useful because you'll
get about ten to 20% control
and those cover crop
will come back.
However, if you wait
until the heading stage,
which is probably not
desirable for feed
because that time it's
like more hards stem but
you'll get about 50% kill
of those cover crop with
the telageaw similar
thing but if you do
like light telge rototill
just to mix up those
biomass with the soil.
Though, in cover
crops situation,
our goal is not to
disturb the soil because
we promote not
disturbing the soil.
But sometimes for
the organic row,
you have to terminate
the cover crops.
If you do light teelge,
rototill, mix up those
cover crop biomass
in the top layer of the soil.
You have to wait until a
later stage because that's
the time when you'll get
about 100% kill
those cover crop.
However, if you do it early
in the tillering stage,
you can get up to 75, 80% kill.
But there will be some cover
crop or cereal rye that
will get established
after the roto tail.
A lot of tradeoffs in this
whole thing, isn't there?
Yeah. Joe, I want to get
back to something that you
mentioned earlier too is your
work with pre herbicides.
And I understand you've
been doing some work
where they're looking
at because the nin,
you've done some work too with
pre emergency herbicides,
with that termination
application of the cover crop.
And there's always
a concern about
interception of the cover
crop, the pre herbicide.
You're going to get
as much activity
and so forth. What
have you found, Joe?
If you want to just
elaborate a little
bit if you can, what
you've found so far.
The effectiveness
of pre herbicides,
when you do have a
cover crop out there,
they have an impact on efficacy
and how much is actually
actually reaching the
soil and so forth.
Yeah. And the trial that I've
been doing that you're
referring to as
part of a national effort,
I think 13 or 14 or so states
involved for those states
took an additional step.
I was not part of that, but I do
know the results of the data.
But if we look at
just the weed control aspect
from using that pre
emergence herbicide in rye,
I'd like to just phrase it as R
plus a pre herbicide
is better than either,
either one of those alone.
If we don't have that rye
cover crop and just rely on
a premergenc herbicide that
will start breaking after
three or four weeks,
which is what we
expect when there,
with a post emergency herbicide,
we might buy an extra,
maybe 14 days before needing
to apply a post herbicide.
If we have the combination
of rye plus a pre,
compared to just the Pre alone.
Or just that rye alone.
I've taken a look at it of
how many days are you buying
yourself until water
hemp gets to 4 " tall.
And looks like, yeah,
about ten to 14 days on
average when you have
that R plus the pre combination
compared to either alone.
Now, the next step
that those four or so
states have taken.
Is taking soil samples from
these plots and trying to
determine where the pre
emergence herbicide actually is.
Because we're always concerned
about interception of
that pre emergent herbicide
with the cover crop.
And the short answer is yes,
the cover crop is intercepting
some of that pre
emergent serbicide.
Forget the exact numbers,
let's just say somewhere
in the range of
70 to 80% of the herbicide
makes it to the soil surface.
So maybe that 20 to
30 was intercepted by
rye compared to a standard
check with no rye.
And the same rate of a
pre emergent supplied.
So based on the
soil core analysis,
we're tying up 20 to 30%
And don't quote me
exactly on those numbers,
don't have the data
in front of me,
but we are tying up some of
that residual in the rye.
But the end result from a
weed control standpoint
is they are also seeing
similar observations
like I have that you are
getting better control with
the two practices combined.
So I know it's
never encouraging to have
some residual tied
up in that case,
but the main point there is that
the overall weed
control is better in
that system even though we are
getting some tie residual.
Bottom line is it's helping out.
Right? That's one question
too that's come up and we got
some of these questions at
registration to,
for this program.
And sometimes people look
at cover crops and for
we control. What do you think?
It's pretty challenging in
a conventional system to get
100% of your weak control
from a cover crop?
We've got other tools
that we can use.
How do you address that?
Double shoot that
over to you first.
Just thinking about people
wondering whether or
not the value that
a cover crop can provide from
a weak control standpoint
in a conventional system.
Yeah.
I think with the herbicide
resistance issues
that we are having in all
of the Midwestern state,
we're struggling with Waterhemp
and Joe can talk about Sia.
We have some herbicide
resistant weed issues in
our states and we
are talking about
diversifying our system.
We cannot only rely on
single herbicide to
mitigate these issues
because you'll see
some Minnesota Crop News article
that is coming out tomorrow
that we'll talk about some of
the Waterhemp survey
we did recently.
And it is showing that
multiple herbicide
registered waterhemp
is prevalent in Minnesota.
It could be registered
to two sides of action,
three sides of action,
45, up to six sides of action.
Those populations
are still slow in
spreading that six sides
of action resistant thing.
But in a couple of the years,
we'll see that registered
treadmill is still ongoing and
most of our waterhemp
are showing resistance
to multiple herbicides.
So that's why we need to
diversify our systems in
terms of management practices,
rotation, herbicide options.
I agree with Joe.
We saw the same thing when
you combine this cover
crop with a pre herbicide.
Probably you'll get
the best benefits
out of this cover crop.
I mean, yes, the cover crop will
add some cost to your program,
but in the long run you'll
get benefits out of it and
you'll get your soil seed bank
reduced in a couple of years.
If you diversify your system
that will help you in long run.
Any thoughts do you want
to add to that, Joe too?
Because I know again you've had
some significant
issues with Kosha and
just looking at
multiple resistance
in that weed species too.
Yeah, that's another one,
just briefly on Kosha
that we also can get
a benefit using rye for
Kosha control because of
that early season biomass.
And that's not work that
I'm doing but out in my
not Dr. Brian Jakes is
playing around with rye.
And then combining rye with like
a fall application of
flumixidenorvalorbiningwo.
Standard practices for Osha
control and seeing
how that works,
a more north central
part of the state.
But whether it's
Kosha or water Hemp,
yeah, we're just getting
more and more
herbicide resistance.
And anyone who teaches
herbicide physiology may
disagree with this statement.
But the simplest
way I think about
it is Ry is basically
another site of
action that we can
use if you want
to simplify it down
to that level,
is that we need
other solutions in
the long term for
control of those weeds
like water, Mp and Osha.
The solution is not going
to come from a jug.
Any new site of action
is half a decade off.
At least I feel like we've been
saying that for the
last half decade.
But we'll see how
long until we actually
do get a new site of
action for major row crops
effective against weeds
like water, him, percio.
If we look at just our solutions
we've been trying to achieve or
accomplish by getting
craftier with herbicide
combinations.
I look towards the south
and Dr. Aaron Hagrid,
University of Illinois,
I think has put it best
when he starts talking
about the metabolic resistance
that they have in water.
Him, we certainly
have some of that
up here and some of our
palm raman populations.
But when you look at metabolic
resistance to herbicides
and the fact that it's almost
unpredictable which herbicides
they will be resistant to.
The Illinois,
they're starting to
reevaluate the standard practice
of tank mixing herbicides
as a good resistance
management option.
There's some line
of thought now that
with these metabolic
resistant pigweed,
that tank mixing may actually
increase the frequency of
how often resistance or
mechanisms occur or resistance
to new herbicide active
ingredients occurs.
When we look at it simply
from trying to control
using herbicides,
that I'm not going
to put a date on it.
Those days are
coming to an end at
some point in the future and
we need to integrate
other tactics.
And that's why we're
looking at easier
to adopt on the wide
scale things like rye.
Now, harvest weed
seed destructors
are now coming into the scene.
Some of these other
tactics beyond
just a herbicide to really get
a handle on some of these
really problematic weeds.
Most definitely.
Diversification is key.
And I see we're just
about out of time.
But any parting thoughts
that you wanted to say here,
Devlin, as you wrap things up?
Early season weed control
here with cover
crops or anything?
Yeah, this year I
am skeptical how
much benefit we can get out of
cover crop because of
the last dry fall.
And spring was also a late,
we got a lot of
snow last winter.
It was late start for
the rye in the spring.
But as we mentioned,
it's always good
to start clean and
stay clean even if you're
adapting cereal rye as one of
the diversification
key in your systems.
It is still good
idea to have a Pre
on in case if you missed
your Pre this year
because talked to a lot of
farmers this year and they're
so busy and they're in a
hurry to plant their crops.
Some of them missed their
pres and I talked to them.
But I highly recommend
them to come back
with a post emergence as soon as
possible or as soon as
they see the weeds.
And weeds are like less than
3 " tall, like tank mixing.
Those post emergence with
certain some type of
residual herbicides
will definitely
help with the water control.
But yeah, that'll be my last
thought for this spring
because we have a little
bit different year
this year compared
to last year now.
Thanks Lin. And
how about you Joe?
Any parting thoughts here
as we wrap things up?
Yes. I'm just going
to take, not a 180,
maybe a 90 degree turn
here and focus just on how
warm it has been this spring
with regards to premergent
herbicides because
we've been warm,
dry in the last week up
here, we've been very windy.
And just a reminder
for folks that
many premergent
herbicides cannot
be used once crops are
starting to emerge,
we focus on soybeans,
things like Fumi Oxygen or
Valor Soft Ventrone or the
Spartan Authority products.
Once the soybeans are emerging,
we can't use those products
due to a high risk of injury.
We've had a situation
up here where
we've planted and just had
30 mile per hour winds
and not been able to
get a Pre on before
the beans come up.
I know we still have maybe 30 or
40% of our soybean
acres to go in.
I'm assuming it's similar on
the other side of the
river up this far north.
Just a reminder,
if you're going to
get that pre on and
we're challenged by
weather just to make sure that
the crop is not emerging because
it's happening
pretty quick here,
certainly within five days
of planting for soybeans,
which is a lot quicker
than we're used to.
Excellent points. I should
note that in the chat,
there's a link to Google Doc
that has a lot of links.
If you have any links
to add to that,
Joe too, we'll certainly
throw those in there.
But again, to the
cover crop website,
more information on
planting green as well too,
because we just pretty much
talked about weed management.
We didn't talk about all the
other potential tradeoffs and
challenges you might
have from like
an insect of things too.
And the need to be scouting for
things armyworm and
things like that too.
But anyway, I encourage
people to check that out.
But again, I better
wrap things up here.
Again, I'd like to thank
everybody for attending
today and especially
our speakers, Dr.
Sang Dr. and of course
our sponsors as well to
the Minnesota Slaving Research
and Promotion Council
and the Minnesota Corn Research
and Promotion Council.
As you sign off today, again,
there's going to be a
really quick survey.
I hope you'll take that.
Also ask for input,
what we should talk about
in future sessions,
things that are concerning you.
Next week we will
have Dr. Sharma
and Dr. Fernandez
on moisture issues,
looking at two dry
and two wet and
supplemental nitrogen
issues again.
Thanks everyone and have
a great rest of the day and
hope to see you next week.