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GSL Range Research Update
Drs. Mitch Stephenson and Jerry Volesky
Drs. Mitch Stephenson and Jerry Volesky discuss current range-focused research projects at GSL.
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Hello, today I'm gonna be talking about
some of our Rangeland Research that we're conducting
at the Gudmundsen Sandhills Lab.
My name is Mitch Stephenson.
I'm a Range and Forage Management Specialist
based at the Panhandle Research and Extension Center.
And then my co-author and also speaker Jerry Volesky,
is also gonna be giving some updates.
And he's out of West Central Research and Extension Center
in North Platte.
We have a number of research projects currently going on
at the Gudmundsen Sandhills Lab.
The first two that I'm gonna talk about deal
with grazing management and also burning on subirrigated
And so we're looking at early season burning
and how that affects subsequent...
Your subsequent hay production.
And also looking at the timing and intensity of grazing
in the fall and winter on subirrigated meadow hay regrowth
and then how that affects the subsequent year hay
Next, I'll talk about some long term vegetation monitoring
plots that we've been establishing at Gudmundsen
as well as other ranches throughout the Sandhills.
And then going into some of the work that we've been
conducting with GPS tracking to look at modeling
livestock grazing patterns across different scenarios
in the Sandhills and other examples.
Travis mullenix and I are working on some GPS
and accelerometer data to define cow/calf relationships.
And we're particularly interested in looking
at how some of those relationships are affected
by differences in milk production by those cows.
And so we're using the accelerometers essentially
like a Fitbit to track behaviors.
And so we're able to look at things like whether
they're grazing, whether they're nursing,
whether they're resting and look at how that varies
depending on some of these differences in their cow.
And then lastly, Jerry is gonna be talking about some
precipitation and plant production research,
some long-term data that we've collected over the past
15/16 years at the Gudmundsen Sandhills Lab.
So the first study that I'm gonna talk about
and the question we were really looking at is how does
burning early in the growing season influence hay production
later in the year?
And so this was a question that was brought to me
by a few producers and they were asking,
what do I do with this excessive standing dead
and litter material in these pastures in areas
that either we couldn't hay, because it was too wet,
or maybe in areas that we graze, but we didn't graze
at a high enough stocking density so they ended up being
quite a lot of biomass left behind.
And so the picture on the left here shows an example
of a meadow here on the Gudmundsen Sandhills Lab
that had quite a lot of biomass left in the early spring.
And so we set up a study where
we set up blocks where we burn these areas,
relatively small areas,
but we collected all the standing dead and litter material
in early May, and we had about 3700 pounds per acre
is what it would have been equated to.
And so we had three years that we burn
these different plots, or we either we mowed them,
or we left them with no treatment, so our controls.
And so we move this around so every year we did a different
location where we replicated this study within the meadow.
Burning and mowing usually occur during the first week
And then we would fence off half of that plots,
so the goal here is so cattle were grazing
within this greater meadow area early in the growing season,
so from early May until about early July,
or excuse me, early June.
And so we thought, well, they're gonna be out here grazing
anyways, let's just see how burning and mowing early
and then having access to grazing would affect it,
or burning and bowing early, and then no grazing
would affect it.
So we did that just by separating those out
and so when cattle were pulled off in early June,
we would go out, we'd clip all the plots,
so we could determine a utilization rate,
and then we would go back in August to see
the end of season biomass that was out there.
And so what we found is that in June when we pulled
cattle off, typically that the burn plots were grazed
at a higher utilization than our control plots
and we expected this.
The research would suggest at many other locations
that if you burn an area cattle are gonna be attracted
to that succulent regrow that comes back on those areas
and they also don't need to dig through all this standing
dead biomass as you can see the controlled plots here.
Quite a lot of that biomass that dead biomass is still there
and so they have to kind of sort through all that to get
down to the grass and so on the grazed compared
to the ungrazed we found there was about 75% utilization
on the burn plots, about 45 ish percent utilization
on the unburned.
So jumping into our August bio mask clipping.
And so one of the interesting things that we found
was that the treatment, whether we burned or we mowed,
did not have much of an impact on biomass production
on either the grazed or the ungrazed plots.
And so these are...
This is the average production for total live,
cool season graminoids.
So that's cool season grasses, sedges and rushes,
a warm season grasses forbs.
And then you need dead material that might have been still
there in August.
And so really the only differences that we found
between our treatments were with our dead plant material,
where we found that there was quite a lot more dead plant
material as we expected in our controls compared to whether
we burned or we mowed it.
And so really from this, we were able to conclude
that early season burning can be a viable tool for managing
subirrigated meadows without any effect
on hay production in mid-August.
We did see that if the plots were grazed though,
the grazing tended to have more of an influence
on the biomass later in the growing season.
So if it was grazed in May to early June,
so regardless of the treatment burned, controlled or mowed,
we tended to see a reduction in the amount of biomass
that was out there.
So for our total live biomass,
it was about 1500 or so pounds per acre less
on the grazed compared to the ungrazed.
But we did see a slightly higher crude protein and TDN
on our vegetation for the grazed compared to the ungrazed
plots, but it was kind of variable.
And we didn't get a really clear picture that trade off
even though other research would suggest that
if you graze early, it'll set back and have more vegetative
plant material later in the growing season.
We didn't see a lot of that but we saw a slight increase
in crude protein.
But we definitely saw a reduction in the amount of biomass
that was out there so there's a trade off there.
So our next question was how does timing and intensity
of grazing on meadow regrowth influence subsequent year
hay production and so common practice that is...
That we do at Gudmundsen and a lot of ranches do
is they'll go out and graze that regrowth on those meadows.
It's a high quality and a fairly good amount of biomass
that's usually there in the fall and winter.
We had between 2000 and 3000 pounds per acre on our plots
And so we wanted to look at this in terms of what if we
grazed in the fall, that was before a really hard freeze
so the plant material was still actively growing,
or what if we grazed in the winter that was post freeze
after that vegetation had primarily gone dormant,
as you can see in these pictures here on the left.
And then so we added in another treatment to this of looking
at if we grazed too heavy, so we're trying to get about 75%
utilization that's intake and trampling,
and also moderate about 50% grazing, 50% remaining
out there in the paddocks.
And so we put a number of these paddocks out,
replicated it four times
and we use some of the sedge officially to cows
to graze these paddocks at the different times
and at the different intensities.
And then we came back the following July and we select...
And we sampled on those different plots.
So jumping right to the data of two years,
so we collected data in 2019 and 2020.
And so this is the biomass of grass
in the subsequent year after we grazed
and so really what we found is that we have about
500 pounds per acre less when grazing occurred in the fall
compared to the winter.
They were both similar with our control,
though that had no grazing.
But it was about...
It was still less numerically
in the pre compared to the post...
To the control and so there appears to be an influence
of grazing before that grasses has gone dormant.
And we think this is likely due to those cool season
grasses, still actively growing,
still actively using some of those carbohydrate reserves
that are then grazed and that shuts off.
And so, there appears to be a difference in whether you wait
until after those grasses have gone dormant.
But our heavy versus moderate grazing really didn't appear
to have much of a difference as you can see,
they're fairly similar within those time periods.
We did see a difference in the amount of subsequent
year standing dead and litter though which we expected.
But we had about 800 to 1000 pounds per acre less
dead plant material when grazing occurred in the fall
or winter compared to not grazing at all.
So there's still quite a bit of standing dead and litter
out there, if you just leave that regrowth
out on the meadows.
And this is where we did pick up a difference between
the moderate in heavy grazing, where we found that heavy
grazed plots had about 43% less dead material
than our moderately grazed plots.
And so this plays, all plays into that meadow management,
it also plays into that hay bale that you're gonna
be producing the following year.
And some things to think about, we plan on collecting
a couple more years of data.
The goal of this is to really look at those cumulative
And so if we're grazing it this way,
for multiple years back to back,
how does that influence that hay production
during the subsequent year.
We started a study in 2019,
looking at monitoring on Rangelands,
and we selected three pastures in the eastern part of GSL
to participate in this program.
And what we were doing with this is looking at variables
on Rangelands that we can measure and track over time,
and across different grazing management strategies
and across different regions of the Sandhills.
The first thing that we looked at was percent ground cover.
And the way that we did this was we had multiple places
where we looked at a single point on the ground across
And so for the three pastures at GSL,
what we found is that they add about 50 to 70% litter,
about 15 to 20% bare ground and about 15% to 20% live basal,
the base of a vegetative plan.
And so but this was variable depending on our sites,
and as we're able to look at a lot of different things
based on differences.
We also looked at frequency of occurrence
and so we had a frame that we would lay down
at a number of locations across our sites that are transects
and we would have presence or absence of different species.
So if it was present, we recorded it.
And this gives us an indication of how frequently
we observe different plant species across our study size.
So as you see here, little bluestem was very frequently
observed in one of our pastures, as well as sedges,
scriveners rose of grass, stiff sunflower, sampling salmon,
and so on.
And so this gives us an idea of what species are out there
and how frequent they are.
We also wanted to look at the amount of biomass
those different species are contributing.
And so this is a method called dry-weight rank.
It's semi qualitative so it's based on visual observations,
but it gives an estimation of what's contributing the most
of the biomass.
And so in pasture two here, we saw that little bluestem
was about 30 to 40% estimated amount of that total biomass.
What surprised us a little bit was the amount
of stiff sunflower that was out there.
And then needle and thread, scribners rose grass
each had about nine or 10%, and so on.
And so this has really given us a good picture
of those plant communities across these.
So this study is looking at it across 10 different ranches
spread throughout the Sandhills.
We actually are moving farther to the east here this year,
where we have 90 to 100, Upland Sands Ecological Sites
that we've put monitoring locations at.
We've seen about 100 different plant species.
Of those about 72% are forbs and shrubs,
which was really important as we look at biodiversity.
In 2020, we did extensive testing for soil health data,
looking at microbial communities,
looking at soil organic matter, soil structure,
a lot of these variables that we're adding into this study.
And in the future, we hope to look at some satellite imagery
data to look at that things across the whole pastures
in terms of bare ground and perennial vegetation.
And so if you're interested,
there's a BeefWatch Article Title of what should my pastures
And the last thing that I'm gonna talk about
is some of our GPS tracking to model grazing patterns
and so this is the study that we are collaborating
with the USDA ARS out of Fort Collins on.
And what we're really looking at is can we model
the Sandhills in terms of their topographic position.
And there's some tools that we have available
that we created this topographic position index of pastures
here on the Gudmundsen Sandhills Lab.
And it basically identifies whether that position
is in the lower area, the middle would be like slopes,
and then the upper areas, which are dune tops and ridges.
And then we have GPS tracking data.
We've collected quite a bit over the years at GSL,
and so we're able to overlay these use map patterns
with the topography and create what we call a resource
selection probability function.
And this resource selection probability function
is the estimate of the true probability of use
of a given pixel.
And so as we look at these maps,
as you see the darker red is an indication that that pixel
is going to be used in a higher degree
than other pixels within the same pasture.
And so if you look, the blue dots represent water sources
as you expected, there's going to be more areas around
the water that those cattle are grazing.
So it's gonna have a higher intensity.
But with the use of the topographic position index
and our grazing, GPS tracking, we're able to look at this
in terms of how does this equate to the different
topographic positions within a pasture.
And so if you look at the darker pink color in these images,
that's typically our low lands.
And so they're gonna have a higher probability of use
than some of our uplands.
And so we can create these maps across large areas
that would help us in better understanding
where we're going to see that higher grazing pressure
and how can we think about different strategies
that would alleviate pressure in some areas
or adjust where that pressure is going in different years.
Now these graphs here show,
basically what we're trying to accomplish in a graph form.
And so, if you think about a pasture having a grid system,
and every grid is about 625 meters squared spread across
And so on the x-axis here,
that's the signal, it goes from zero to 20 to over 200.
So basically, that's the relative frequency
of the cattle grazing on those areas.
So zero to 20 is not grazed at all, hardly,
over 200 would mean that those grades are grazed
at a really high rate.
And so on the y-axis, we have percent of the pasture.
And so if you think about this, in terms of that red line,
so that red line is how those grids stack up
compared to the whole pasture.
And so if we have a lot on the left side of a graph,
that means that there are a lot of areas in that pasture,
that are only lightly being grazed.
And if we have a lot on the right side of the graph,
that means there's a lot of those grid pixels
that are being grazed very heavily.
And so if we look at Gudmundsen, for example,
we really see that there is a skewed left to that.
Meaning that there are a lot of places in those larger
pastures that aren't being grazed.
But then there are also a spike at the greater than 200,
where they have some areas that are being used very heavily.
And this is typical what we see in a low stock density
large pasture areas as what we expected.
Now we also have data from the Barta Brother Ranch
and these are smaller pastures, higher stocking density.
They're managed in a rotational...
Fairly moderate rotational system for pasture
for rotation, but the small pastures especially I think,
have an influence on this.
And as we see this, it shifts it to the right more
in terms of how those cattle are grazing.
So they're grazing more to the center.
Now, this is a normal distribution
and so we this what we would expect if it's a fairly uniform
distribution across the landscape,
that most of our points would fall between that 80 to 140,
right in that middle part of the graph.
And so if we look at the differences between these pastures,
GSL tend to be skewed a little bit more left,
Barta Brothers tend to be be more towards the middle
part of this figure.
And so, more towards that uniform utilization.
And so the research here suggests that there may be some
opportunities to look at this more look how different
management might affect grazing across the landscape,
and really give us more insights
of areas that are heavily used and areas that are lightly
And so this is a publication that we did in conjunction
with sites across the west, New Mexico, Idaho and Colorado,
and other places.
And so, we're hoping to look at this and glean
more information on how cattle utilize different pastures
and how we can predict where they're gonna utilize
it in the future.
Afternoon, this is Jerry Volesky,
Range and Forage Specialists
at the West Central Research and Extension Center
in North Platte.
And Stephenson is gonna briefly cover some of our range
and pasture conditions and what we've been seeing here
This is a Drought Monitor from August 11 and as you can see,
in Nebraska, the Western part of the State,
Southwest, South Central and the Northeast
have some different levels of drought conditions.
Our neighbors to the West, Wyoming and Colorado
pretty much statewide have varying levels of dryness
or drought taking place.
This map here is presenting the percent of normal
precipitation since April 1 are basically our growing
season so far.
And you can see in the areas of red that really
are relatively to what we saw on the Drought Monitor
very dry conditions but then also,
the bullseye almost very wet conditions in parts
of Southeastern Cherry County, Brown Rock,
Blaine Counties right there in the middle of the state.
Now this is a similar map from July 1,
and that trend has somewhat continued
it's a little bit more irregular in terms of areas
that have received rain fall since July 1.
This table here shows the GSL precipitation through July
of this year.
And the two key things are both April and June are quite...
And then on the opposite end of the spectrum,
both May and July were a bit above average
in terms of monthly total precipitation.
Now here's a table of our mid June production
on upland range both at the Gudmundsen Sandhills Lab
as well as at the Barta Brothers ranch.
So in 2020, at Gudmundsen,
we have actually a bit above average of the cool season
grass and sedge production,
likely bolstered by that above average rainfall in May.
Overall then the total grass and forbs and shrub production
was about a long term average here in 2020.
At the Barta Brothers ranch, the wet location,
cool season grass production, excellent at over 1100 pounds
And the total production at Barta Brothers at mid-June
was 1700 pounds, which was about 500 pounds
above the long term average.
So it's really a tale of extremes across Sandhills
in terms of these drier and wetter areas,
of course in the dry areas, so we like to expect
reduced upland pasture production and maybe your pastures
are looking a little bit shorter here now in August,
than you'd like to see and then and likewise
in those subirrigated meadows in the dry areas.
So rainfall is important, and so it's likely
that you probably had less hay production than you might
Now on the other hand in these wet areas,
again, we're seeing some reduction in hay production
because of extremely wet meadows and standing water
in some places.
It's also interesting to note that again,
in the wet areas on some upland sites so where we have
introduced swales, we call them are really close depressions
that with the excessive rainfall for the past two years,
we have a lot of standing water in these sites
and these are not subirrigated, it's just an accumulation
of water over the past couple of years that has basically
flooded some of these inner doodle sites.
So with that, I thank you for your time
and feel free to contact me if you have any more questions
or would like to discuss any other range or pasture
types of situations.
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