Importance of Natural Resources

Using RUSLE2 to Evaluate Soil Health Planning Principles


Now again, I want to
welcome everybody. Again, this is David Lamm. I’m the team leader for
the National Soil Health and Sustainability
team that functions out of the East National
Technology Support Center. And again, I want to welcome
everybody to today’s webinar. First, I want to take a minute
to introduce our speaker. Then I’ll introduce his topic. Mike Kucera, who’s an agronomist
on the Soil Ecosystem team out of the National Soil Survey
Center in Lincoln, Nebraska. Mike’s an old-timer like me. He’s been around a long time. He’s served in a number
of capacities– range conservation, soil conservation,
FDC, those types of things. He’s got a tremendous
amount of knowledge in the practical aspect of it. And then he’s also done some
work as a State Agronomist Water Quality Specialist, and
he was even a State Resource Conservationist in Nebraska
for over seven years. Anybody who could survive
that kind of a work career has done a lot. Mike’s got a particular
interest in soil health. He’s, again, worked
a lot out there on ecological site descriptions. He’s developed the
Soil Quality Bucket, which is, I guess, a poor man’s
version of the Soul Quality Test Kit that’s getting
a lot of use out there. And most recently, I’ve been
able to work with Mike as part of the training cadre for
the Soil Health 101 effort that we just wrapped
up, that we went out and trained over 20 states
plus the Caribbean area. We trained almost 3,000 people
between the NRCS, farmers and partners. So we’re really
proud of that effort, and Mike participated in
two trainings sessions. Not only has Mike been
a NRCS career person, but he also does it on his
own personal farm there outside in the central Nebraska. And I’ll let him
describe where it’s at. And I had the privilege
of visiting Mike’s farm last year as we were doing
some soil health training there for the employees in Nebraska. So I say that because
today’s topic is one– I’ll be honest
with you folks– this was voted on by you folks. Every year, Holli does a
survey, and we try and list the top 10 or 12 topics
for this upcoming webinars. And this one linking RUSLE
and soil health together was ranked right up there. And I was quite surprised,
to be honest with you. But anyway, when we
went to seek a person to do this presentation,
Mike’s name came right up. And I think Mike is going
to– his background as an SRC, and using RUSLE and then his
involvement in the soil health movement has really
linked the two together. So we’re really
fortunate to have Mike. And I’m going to
introduce the topic and then turn it over to him. He’s going to talk about Using
RUSLE2 to Evaluate Soil Health Planning Principles. And what that, Mike, I’m
going to turn it over to you. OK, thanks, David and Holli. I appreciate the
support, and I thoroughly enjoyed doing the
soil health training, getting around to
some different states. And like David said, I
do have a dry-land farm in central Nebraska. We’ve been in no-till
for about 24 years. And to give you an idea how
long I’ve been around SCS, NRCS, when I started doing soil
loss calculations with USLE, and the wind-erosion equation, I
had the old red and green slide rule. So that’s how I
started and learned, using that with
conservation planning. The first slide here
just shows Gordon Mickel, the State Agronomist
in South Carolina and I in Georgia
a couple weeks ago doing Soil Health 101 training. We went around to the four
areas around the state, and I learned a lot about
health management systems in the Southeast. That was awesome. Then on the right, we worked
with 150 VoAg educators here in Nebraska, and put
together soil quality buckets for them, looking at
soil physical, chemical, and biological properties. And then how to simply
and quickly assess that in the field. And then they, in turn, would
work with their students. So that effort has blossomed,
as David mentioned, where states have picked up
bits and pieces of the bucket as they see fit. Also, before I get
started, I’d like to thank– I did work with
Giulio Ferruzzi and Linda Scheffe the people who
work with RUSLE support, both from a database
and a technical end. And so they have been able
to review this as well. So if you get into
those deep questions, those two are the contacts. OK, just quickly, we’re going
to go through the Soil Health Planning Principles. And as I tie this
back to RUSLE2, I’m going to show how each
planning principle is covered in RUSLE2 and in your
soil loss calculations and the other outputs we get. So the first, again, it
disturbing soil less. And we’ll talk about
that more specifically. There’s different
types of disturbance. Using a diversity of
plants to add diversity to soil microorganisms,
growing living roots throughout the
year– and that one is really crucial
for soil health and in accelerating that–
and keeping the ground covered as much as possible. And then I have two
footnotes at the bottom. The one I added there, on Manage
erosion and compaction is huge, because really managing
erosion and compaction go right along with those
four planning principles and are very important to
achieve our ultimate goal, which is have the most favorable
habitat for the soil food web that makes the soil function
much more efficiently for all of the different
functions the soil would have such as nutrient and energy
cycling, water partitioning, et cetera. As you get into soil health
management systems and the soil health planning principles,
those principles are tied directly to erosion
and erosion prediction in many ways. And here you see
a field day that I was at where we are
keeping the ground covered, and also on the right we have
some growing living roots. And you can see
on the far right, we have very little
runoff and erosion. Those are basically
native– even the second one from the right
is the native good aggregate structure where we still have
virtually no runoff, even without residue. So you can take a look. Really it ties together. Outputs in RUSLE that
we have– currently there’s actually four. That’s the erosion rate sediment
delivery, soil conditioning index– which I’ll cover
more with organic matter trends– and then STIR,
which is a disturbance rating for operations. Those three directly relate to
soil health planning principles I talked about earlier. The other two– fuel energy
use, and then grazing tool would come in the future for
doing basic grazing planning. To start out, the Field Office
user or other general public can actually download and
use RUSLE and also get our soils database that
goes with whatever area you’re working in. But they have to select
those five things or build– in the case
of crop management– they may build
them on their own, but their climate, their soil
map component, their slope length and steepness, and then
build their crop management system, and then
supporting practices that they may have such
as contouring, terraces, those types of things. The next screen that
will come up here is in the profile
view in RUSLE2. Again, that ties to
that previous slide where we have to the five
steps, and it shows you what it looks like– the
location, the soil type that we’d bring in. And the example that I
did here was in a county that I was a soil
conservationist in just to the east southeast of
Lincoln in Otoe County. And then our management–
I’ll talk about that more– and then
modifying or building that sequence, your
different operations, and then your
supporting practices. The way that RUSLE2
works is I’m showing that what’s called
the CMZ map, which is Crop Management Zone map. And the zone that I
built my example in was in Crop Management Zone 16. Lincoln is in the far west end
of Crop Management Zone 16. And the Otoe county just to
the east southeast of Lincoln. Within those Crop
Management Zones, we build similar rotations
and planting dates and all of those
that were set up based on similarities
within those zones. This just shows the example
here that I did in Otoe county for a corn, soybean,
wheat, with a cover crop of hairy vetch following
our winter wheat operation. So again, both the
operation and the vegetation are built into these
crop management sequences with common yields, et cetera. Kind of the nice thing– if
you’ve heard about soil health management systems,
they’re basically a group of conservation
practices and could be other measures you use to
achieve those four planning principles I mentioned earlier. They directly relate
to management systems we build in RUSLE. And this is what’s
called a worksheet view. And in this worksheet view,
I’ve got three different systems in there– corn,
soybeans, no till. We’ve got corn, soybeans
with cover crop. We got corn, soybeans,
wheat with a fall cover crop following wheat harvest. In this screen, we can
show or compare soil loss. We can show or compare
soil conditioning index and our STIR value,
and our fuel use. So it’s a nice way to compare. And then if you want
more information, you click on the
folders, and drill down into that information for what
you want to know more about. The first planning
principle– there are three types of disturbance. Those of you that have been
to the soil health training that I helped to assist with
across the country– those include physical,
chemical, and biological. And the two that I have in red
there directly tie to RUSLE. So we build in our
physical disturbance through all our
different operations. And then the biological,
the grazing part of it, we can build grazing and
removal of those biomass, either growing or
our crop aftermath. They chemical is not
built into RUSLE, other than when we do
fertilizer application– the actual operation itself. So all three of those can
be a disturbance of sorts. And in the physical is obvious. We do tillage. Chemical can be in
fertilizers and pesticides. For example, if we
over-apply fertilizers, it can affect our soil food web
and then of course biological. Start out with the physical, and
how does this relate to RUSLE2? In our no-till
systems, or if we’ve got a perennial vegetation,
the soil block diagram on the far left
side shows what’s ideal for our entire soil
food web, especially when we get to the earthworms, and
some of the macroflora that’s in the soil. As we start doing
disturbance, for example, the second block
or the middle block shows a chisel plow, which–
in case of a chisel plow is going to be primary tillage. And then we go to
the far right, where we do lots of different
secondary tillage, maybe with a rototill,
a disc, et cetera. We slice and dice and create
that artificial porosity and reduce our bulk
density temporarily. So as you move to
the right, it’s less and less favorable
for a soil food web. And all of those are
simulated in RUSLE. OK, again, physical tillage–
we talked about that. Two things that are in RUSLE
is the operations databases. We have all types of equipment–
includes harvest equipment, includes tillage equipment,
includes cultivation, post crop emergence, even spraying
and fertilizer applications. Then, of course, STIR–
I’ll talk about that more. That simulates the
amount of disturbance for that particular rotation. Biological and physical–
how is it modeled in RUSLE? The first item listed
there is the impact of flattened residue
versus standing. So RUSLE predicts
based on the type of harvest equipment you use
and the tillage equipment, how much of the residue
is flat versus standing. That’s very important, because
if we have residue that’s flat and on the
surface of the soil, the soil microbes are going to
decompose that residue quicker than if it’s standing. So if you want to manage to keep
your residue from breaking down as quick, you’d want to keep
it standing, or for snow trap, that type of thing. But RUSLE2 would predict
the amount of each. The impact and type of
residue is very important, and that’s directly tied to
the carbon and nitrogen ratio. I’ll talk about
that, so our residues that have a lower
carbon to nitrogen ratio will break down quicker. Also, the climate impacts
the decomposition rate tremendously. So if we’re in a humid, moist
setting like southeastern US, we’re going to break
down residue quicker. If we’re in a dry and cool
setting, then of course, for climate, it’s going
to break down slower. Chemical disturbance– again
pesticides and fertilizers talking there– the only
thing that RUSLE evaluates relative to chemical disturbance
is the field operation itself. So it doesn’t give
us any prediction, for example, if I over-apply
nitrogen fertilizer– say I apply twice too much–
what does that do? It speeds up your organic matter
mineralization, your residue mineralization. So it doesn’t predict that
at this point in time. Also, of course, if we
over-apply pesticides, it can favor certain
soul microbiota. So it does not do that. Of course, it does look
at the biological aspects relative to removal of biomass. Also, we can use
grazing to terminate crop growth and the
impacts on the root systems as well as
above-ground biomass. OK, RUSLE2 uses
STIR, and we have this applied to our standard. For example, I believe
the no till standard has a minimum STIR rating
of approximately 20 or less. So it models that based on
four primary parameters. One is how fast do we go through
with our tillage equipment? Second is the type of tillage
equipment that we’re doing. I’ll talk about that more. The depth– how deep do
we pull the equipment through the field? And then, of course, the
percent of soil area disturbed. And that includes splash. And what splash is, is
as you go through a field and the soil particles are
dispersed across the row, it includes areas that
have sail splash as well. This is just a list of a few
different types of equipment that are in RUSLE. And what we have is the
recommended operating speed in miles per hour. We’ve got the tillage type, and
we have four different tillage types. We’ve got mixing and inversion. We got lifting and fracturing. We’ve got compression only,
and then somewhat less mixing and inversion. And then it also lists
the recommended depths. It also lists the
surface area disturbed. And with that, the
higher the number, the higher disturb value,
so the more disturbance that you get for that
planning principle– so disturb the soil. Also, obviously, as we
increase our surveying, it’s going to impact
residue cover, and the planning principle
of keeping it covered. Here’s an example of
a two year rotation. From the database,
you’ve got a STIR value. A field user would
pick the operation that fits as close as possible
to what the farmer’s using. And then you simply
total those up. In this case, we have
a two-year rotation, so we divide the total of
the STIR values for all the operations by two, because
we have a two-year crop rotation. So we have an average of
the 51.3 STIR value, which is fairly intensive
tillage system compared to what our no-till
standard would be, which would be less than 20. Everybody remembers
the early days of CSP. In Nebraska, when I was
SRC, we had the CSP sign up, and we had some
producers put together a field day for
Dave Lightle and I and the State
Agronomist in Nebraska. And this is a stock slicer. Sometimes they’re referred
to as a stock puller. And in case of a stock
slicer, it’s more slices. It goes down the ridge. A stock puller would have a
little flatter disc blades and actually pulls
the stump out. And they do that either
in the fall or the spring on ridges that have been built. That’s just a photo showing it. So what we did here
was take a look at a lot of different tools
similar to this, and rate them or go out and
measure in the field, and compare that to what
values we had in RUSLE2, to see if we’re
somewhat accurate. In this case, the stock slicer,
which more slices the corn, for example on the
top of the ridge, has a tillage intensity of 0.4. It has a recommended depth
of one and a half inches. And then it’s got a
total of, I believe, 40% of the surface
area is disturbed is what the estimate is. So when we were in the field,
we also measured ridge height. And then we measure
horizontally as well, to see if that
40% disturbance is similar to what the
database has in it. OK. Disturbance continues, so
keep the planning principal of disturbance. We’re looking at, in RUSLE,
we can adjust the burial rate. For example, if that
producer runs his tillage deeper or faster, we can
adjust up or down 30%. Again, if you have
agronomist privileges, you can adjust the speed. That can impact it as well. In addition, other
processes that affect how much cover
we’re going to have, and how much disturbance we
have, is kill vegetation. So we can kill vegetation
various different ways. I talked about grazing. I talked about herbicides. There’s other ways
to kill vegetation, such as rolling, et cetera. So you can build that
into your operations. Also, your operation
flattens standing residues. That’s important for either
increasing ground cover, or enhancing how quick
some of that ground cover could break down. Also begin growth, and harvest. Here is, in the
database, each operation. As you go through the
field, it will give you a prediction on how much
of the existing standing residue will be flattened
by that operation. As you go through
with your tractor, you’re going to knock
down standing residue with the tires, as well
as the type of drill. And this example
is a single disk. So a double disk would
open, or, for example, would flatten more
than a single disk. And also it depends on the type
of residue, so wheat, soybeans, and corn– corn
15% of the standing and flattened, soybean
30% in this example. Biological disturbance– talk
about root growth and that, and how that impacts. That’s built into RUSLE,
both at a four-inch depth and the total depth. This shows some
grazing operations where you can do grazing stubble
or grazing perennial cover– heavy, light hoof
traffic, so you can get different
levels of disturbance. Grazing disturbance in RUSLE–
some of the things that you can adjust or use in the RUSLE2
software is aftermath grazing, forages– removal reduces
your canopy height, which is important
for keeping it covered as well– also the
impact of root systems and regrowth of vegetation. So as we graze off
that vegetation, you’re going to have some of
that vegetation grow back. So that’s built into
it, and of course, to terminate, and in the
future for forage balances. Increasing
diversity– this shows you just some ways
of doing that. At soil health planning
training we did recently, these are some of
the things that look at for benefits
for diversity, and rotations, and how
you could accomplish it, either with rotation or
by adding cover crops. Mike? Yeah, go ahead. I got a few questions that
came in, so you [INAUDIBLE] before we move out
of that principle. And I just want to
remind folks, again, if you want to ask
some questions, go ahead and type of them in
down in there in the notes section, and I’ll try and
read them as we go along here. But I apologize for
interrupting here, but there’s a couple questions. The decomposition–
is there a way– one of the realities
of healthy soils is, because of the biological
activity in the soil, it seems to accelerate
decomposition of organic matter. Is there any way
within the RUSLE to adjust or account for
that type of activity? Right now– and Linda Scheffe
is here with me as well, but what RUSLE2
does is, basically the decomposition is tied
to some standard values for the climate you’re in. It’s also tied to whether
you irrigate or not. If you irrigate, you
speed up mineralization. And then it’s tied to what’s
called a decomposition coefficient for the residue,
which is directly related to the carbon-nitrogen ratio. So as far as adjusting it
for– in my case, where you have a diverse rotation and
long-term no-till where I’ve got more biological
activity, it does not do that at this point in time. OK, and then CO2
emissions– is there– with all this estimated
decomposition, is there any way to link or
estimate how much of that residue as being
decomposition is actually being lost into the
atmosphere as CO2 emissions? Really, the only
thing we have in RUSLE that would somewhat directly
relate to estimating CO2 emissions is our soil
conditioning index. So our soil conditioning
index just gives you an indication of
whether we’re building soil organic matter or not. And the only way that
you can sequester carbon is by building soil
organic matter, and/or slow down the amount
the residues themselves, how quickly they decompose. So that’s really the only
thing in RUSLE right now. OK, and then one last
question, and I’ll shut up and let you
keep going there– a question about related
organic matter levels. Is there any way to adjust
for higher organic matter soils versus low
organic matter soils? Is there any way that RUSLE
can accommodate or measure that difference related to
infiltration and water holding capacity and those
types of things? At the very end of
my presentation, I’ve got a slide on
variable k factors. So if you had a soil
scientist or somebody out there that could evaluate
those specific conditions, you could use something
other than the default soils, to basically use a soil with
a different k factor, which reflects soil organic matter,
permeability structure, et cetera, which is
what we [INAUDIBLE]. So that’s really the
only way to do that. OK All right, well
listen, again, folks who want to
ask a question, don’t hesitate to type
them in, and Mike, I’ll let you get back to
your presentation. OK, this is a
screenshot showing you all the different databases
that are in RUSLE. And I’m just showing
some vegetations. So we have various things
in there, as you can see. Planning principle
two– diversity and how does RUSLE model
that and relate back to that planning principle? One, we got our crops. They’re perennial,
annual, and we could even have a biennial crop, for
example, or double cropping. All of that ties into our
cropping intervals or periods, keeping the ground covered,
keeping a diverse root system, et cetera. Planting tillage maturity
dates– we can adjust those, so if we have plant a 90-day
corn versus 120-day corn, we can work that into
our harvest dates and our maturity and
our growth curves. Termination– we might be
planting a cover crop we only want six to eight
weeks of growth, especially here in the semi-arid
areas as you get further west. We don’t want to let too
much vegetation grow, so we can terminate, and
it’ll stop that growth. Climate– we talked about
that– affects growth and decomposition,
your rainfall amount, and of course, your temperature
affect decomposition as well as growth. And then diversity is a major
part of our soil’s conditioning index rating. I’ll talk about it more later. This just shows you a
brilliant feed packer that was used in the southeast. They’re using it in this
case to roll down this rye cover at same time they’re
spraying the cover. So we can build these different
operations into RUSLE, and how does it impact? In this case, obviously, almost
all of our standing residue is going flat, and
we have green residue that’s being terminated. So we would build
those operations into the RUSLE2 operations
for that management system. Cover crop role in
diversity– and I’ve listed– item one and three–
we can build those into RUSLE, so we look at cropping
periods within RUSLE2. Also, we can terminate that
cover crop– for example, in getting the amount
of growth that we want. And then, of course, it shows
all four of those things are the benefits to cover crops. Within RUSLE2, we look
at plant morphology. We look at whether it’s
a broad-leaf grass, how that plant grows. We look at growth habits for
cool season, warm season. It also predicts the
root mass that we have, and when that root
mass and biomass occur within that growing
season, depending on your planting date. So that would cover
principle two. David, do we have any more
questions on principle two? Yeah, we actually do, Mike. The question about
how would you account, with all the interest in
multi-species cover crops, how would you even begin to
piece something like that together in RUSLE? That’s a very good question. I haven’t thought
about that that much. But what you’re going
to have is you’re probably talking about
a cocktail mix, where you might be planting cool
season/warm season mixtures. There are some
examples, or there are some of those mixtures
built into the RUSLE2 database. So you would need to work
with your State Agronomist, and make sure you get
those vegetations added to your RUSLE2 database. And what you should
really be doing is going out to the field, doing
some clipping and monitoring of those cocktail mixes on
what kind of growth you have, so we get growth
curves that fit those. And also, this is Linda Scheffe. There’s a national
plant materials center cover crop study
going on right now. We have the first-year
data that we’re going to be incorporated
into RUSLE2. But we would welcome any kind
of local data like Mike said, as you go through
your State Agronomist. And we appreciate hearing any
requests for additional cover crops that we don’t
have in the database. Well, OK, thanks, Linda. One more question–
the idea, I mean some of these
multi-species mixes you’re hearing, seven or
eight tons of biomass, is that something that could
be adjusted in the model? Because that is probably a
little higher than what maybe you’re used to using or seeing
in your cover crop selection. Is that something that
could be adjusted? Yeah, you can adjust yields. And also the growth
curves, and that’s part of the plant material study
is to predict some of that. But we try to generally go with
averages, rather than doing it for every– my experience,
for example, we had huge CSP
sign-up in Nebraska, and we had thousands and
thousands of these runs to do. We use templates, but
just time will kill you if you do too much of it. Again, it’s a model. We’re trying to estimate,
not necessarily get exact measurements. All right. Thanks, Mike. OK, there are some
of the benefits of keeping living roots
throughout the year. And this is huge when it
comes to soil biology because of the exudance. And if you don’t
have living roots, you don’t have a
living plant out there. You’re missing all that
opportunity to sequester, to take carbon, and the
energy, the photosynthesis process– you’re just
sitting there idle. And the microbes
aren’t as happy as if you’re feeding them
and making those plants work for you. Living roots– how do
we do that within RUSLE? Again, we talked
about a climate, which is growing season
temperature and precipitation. So we use that
climate to help us predict what kind of
growth and growing season we would have based
on those variables. There are types
of root production as well as our biomass,
so RUSLE2 accounts for both living and dead
roots throughout the year within that four-inch level
as well as the entire profile. So the four inch is
important, because that’s more important for
erosion prediction. Again, I talked
about growth curves. Also, we have growth
curves for biomass as well as root
production, and again termination dates and grazing
impacts on root systems. How to keep a living root
throughout the year– this is just some strategies. You could probably add your own. If we have a corn-soybean
rotation here in the Midwest, where
we’d add a winter crop or cover crop like
wheat or cereal rye, double cropping as you get
further south and that works. We can adjust our varieties,
do all those different things. Root systems are also
built into RUSLE2, and I’m just showing a nice
shot from the Phillips Petroleum book that I got as my first
job as a Range Conservationist with SCS. And you see the different
root systems– the fibrous, the tap root systems. RUSLE2 has that built into
for the annual crops as well. And just to drive
that point home, this is a slide shot that shows
a cereal rye, hairy vetch cover crop, both the time of year and
the amount in pounds per acre within that top four inches. RUSLE2 will also predict
this for the entire profile. So we get something like cereal
rye with a highly fibrous root system, you can see
the production is over 2000 pounds in
that top four inches if you let it grow long enough,
and you get it planted right. If we plant it too late
in certain climates, we’re not going to
get that growth. We’re actually going
to be a negative impact on the amount of cover
we have if we go out and try to grow it too late. So you need to know
your vegetation, when it’s likely to grow
and that thing. Look at soybeans versus corn. Soybeans– there’s another
fibrous rooted crop. So you don’t have near as much
biomass in that top four inches as you would corn or for sure
cereal rye, a small grain. What are we trying to do? Think about this in
the erosion standpoint, but also other things like
off-season nitrate losses. We’re trying to keep that
living root throughout the year so we avoid those losses
in those early spring and in late fall,
winter time periods. Here’s just some photos. This is a photo
from Pennsylvania. This shows RUSLE2’s going
to predict your growth. You can see we have
more growth when we got the hairy vetch
planted a little more timely. Here is a photo of when I was
SRC, my no-till specialist Dan Gillespie, his farm. We blew on cereal rye . And he has center pivot, so he
could put the water on, and get good germination. And you can see what it looks
like– a nice, green mat when he’s harvesting his soybeans
just a couple weeks later. Cotton defoliation– we
can build that into RUSLE, in this case trying
to get a little more growth on our cover. OK, so that’s planning
principle three. David, any quick
questions there? Yeah, I got a couple here, Mike. One, so let me get
this straight– so we can use RUSLE
to estimate root mass and vary the planting
date of the cover crop to show the
difference between a, say, September 1st
versus October 1st or October 1st
versus November 1st? Yeah, what you will
do is RUSLE2 has a growth model built into it. And if you plant later,
for example cereal rye, you’re not going to get
as much vegetative growth, or you’re not going to
get as much root mass by planting later. Now that just seems
like that could be a powerful tool
for selling folks on the importance of that
earlier planting date, just to get, like
you said, those roots and get the exudates and
those types of things. And kind of related, I think
I can get this question. This is actually
a user out there, and they said when they
enter in the drilling a cover crop of a
rye grass in RUSLE, oftentimes your soil loss is
worst in a no till situation. And they’re wondering if the
short term benefits of loss of residue should be
outweighed by the benefits of the long-term cover crop, or
are they doing something wrong? Yeah, it makes sense. They’re not doing anything
wrong, but in some cases, you can actually– if
you plant too late, what you’re doing
when you run the field through with the drill, you’re
actually taking the standing residue, making
it flat, so you’re speeding up the
mineralization of the residues from the previous crop. In addition, you’re losing
some of your residue cover, your ground cover. And then if it’s
planted too late, and you don’t get enough
growth or canopy cover, then depending on when
that starts growing again in the spring, you may
gain or you may lose. But quite often, in most
cases, in most climates, it’s a huge benefit to have
a good growing rye cover in the spring when we’re likely
to get spring rains and more erosive rains where we
don’t have a crop canopy. So in most cases, it’s
going to be a positive. But in some cases, it
could be a negative. So all the more reason to get
it seeded in an earlier fashion there. And then one more question. I’ll let you move on. And the question is, is
the root mass information displayed in the
RUSLE output anywhere? Is that something they have
to dig somewhere and find? Yeah, you can go into profiles,
and you can do a right click and create some
nice little graphs. I’m going to show you some
examples here in a second. I’ve got some nice examples. And I did that. Any user can do that. So I’ll show you the
graphs you can pull out. Let’s jump into
planning principle four. And there’s the pros or the
benefits of keeping it covered. Keeping it covered means both
live biomass and dead crop residues. So both provide benefits
for various things. Bottom line, both
are both food sources for our total biology, which
is important to healthy soils. OK, I got quite a
list there, but these are all the things from
the top of my head. And Linda’s here. There’s probably some I missed. But these are the different
things built into RUSLE that relate to
keeping it covered, either through that living
biomass cover or the residue cover. So climate– we
talked about that. We got erosion index. More erosion is likely to occur
in different parts and times of the year,
depending on rainfall. Growing season– you
have different climates across the country, temperature,
precipitation– all of that impacts our cover, our growth. It also impacts how quickly
residue breaks down. Biomass production– the amount
and timing of that biomass– do we have the biomass growth
when we need it to keep it covered to prevent
erosion and run-off? Or do we have that
biomass out there when we’re less likely to
have erosion and run-off? That’s all built into it. Irrigation and water inputs–
this is one a lot of people haven’t thought
about, but if you add irrigation water
in RUSLE, it actually increases your growth. It also increases your
decomposition of your residue. It also can increase
erosion, because you’re changing your antecedent
moisture conditions. So you’re more likely to
get erosion and runoff if you’re closer
to field capacity. Canopy and residue cover–
I talked about that. It predicts flat
versus standing, and that’s huge in my case
where I’ve got wheat stubble. I want to keep it standing. So if I’m going to go out and
put a cover crop in the wheat stubble, I want use
a drill or something that minimizes how much of that
standing residue goes flat. Drilled versus wide
rows– RUSLE2 well predicts the canopy cover. If I go with drilled,
narrow row spacings, I’m going to get that canopy,
keep it covered quicker. We’ve also consider
canopy shapes for different crops,
which can be important. Some crops have a better
canopy to prevent that raindrop impact. Growth curves–
we mentioned that. We can add residue inputs,
like mulch or manure. And it’s got different
types of manure that have different
decomposition rates. For example, chicken litter
is very high in nitrogen. It’ll break down much
quicker than feedlot manure. All the different operations and
timing of those, and of course our disturbance rating we
talked about earlier with STIR– so quite a few different
variables in there to consider. I got this right out of RUSLE. I’m just using this
as a simple user. I can go into canopy shape
for my different vegetation, and it’s got different
canopy shapes. That impacts keeping it covered
and the impact of raindrops for erosion purposes. In RUSLE, if you drill down
into your canopy cover, you can do a right click, and
print out a graph like this. This just simply shows for
corn in Otoe County just east of Lincoln, the percent canopy
cover for 150 bushel corn. You can see 75 days
through 135 days, I have close to probably
95% canopy cover. And then when my corn
starts to go dormant, I start to lose
that canopy cover, and then I lose it
entirely when I harvest. That’s the residue database. There’s a whole list
of residue types. And again, they all
have different carbon to nitrogen ratios,
which are reflected in their decomposition
coefficients. This is the graph, David,
you were asking about. I did these myself working
with RUSLE2 on my laptop. And so I took that corn,
soybeans, wheat rotation with a hairy vetch cover crop
planted after wheat harvest. So you can see on the top
part– that shows the total root biomass production. And for example, for corn
we’re close to 2,000 pounds of total biomass production. For soybeans, it’s a
little over 800 pounds. Wheat we can get up
close to 3,000 pounds. And then of course that varies
during different times of year. So it shows you. And it’s really
closely correlated with the second chart, which
is biomass production or canopy cover. In this case, instead
of percent canopy cover, I did total production
in pounds per acre. So you can see they relate. There’s a little
bit of a lag there. So both of those are really
important for soil health and keeping a living root. You can have an idea of when
those plants are actively growing, and also keeping
it covered for the biomass. And then at the bottom
is the residue cover. And so this is
flat residue cover. At RUSLE2, you can get
estimates of those. And you’ll see,
for example, when I put anhydrous and planted
my corn into my wheat stubble slash cover crop residue, I
had a slight spike or increase in flat cover. What I did there is I flattened
some of the standing cover, so you’ll see some spikes. Also you can see, like
in the soybean year, where I plant my
wheat into soybeans, I lose my residue real
quickly on soybeans because it’s got a very
short half-life compared to something like wheat. Wheat stubble has a very
much longer half-life. OK, so also you can pull up
a graph like this in RUSLE2, which is called Water Erosion
Index for your specific county. This is for a Otoe County. And you see how the
most erosive rainfall events– this is a
daily graph, so it spikes in the middle
of the summer. So very, very little
potential in the late fall through the winter. Also, this is from the
vegetation database. I pulled up the
amount of residue, the total residue on the right,
for my 55 bushel soybean, 60 bushel wheat and
150 bushel of corn. So you can see corn has nearly
8,000 pounds versus my soybeans and wheat, about
3,000 total pounds. But then you take
a look at that. The soybeans, which is smaller
residue– it only takes about 500 pounds
to get 30% cover. It takes about 3,500
pounds to get 90% cover, versus a larger
residue like corn, it takes– to get
90% ground cover, it takes almost 7,000 pounds. So the smaller the
residues, the more ground cover you’re going to
have to prevent erosion. So wheat will give you
more coverage just because of the size of the stubble. That doesn’t tell the
whole story, however. You also need to know how
long that residue’s going to last to provide that
protection for erosion control, and keep it covered for keeping
our soil temperature down. So what do we have here? We have soybean residue. It’s got a very short half-life,
so it disappears quickly. Cotton residue would be
similar, versus wheat stubble, which has a high lignin
content, will last much longer. So the half life of
that is about 80 days, and then corn residue
is kind of in-between, because we’ve got
the fines and then we’ve got the corn stocks
as well built into that. What happens to residue? And this is going
to depend somewhat on your climate,
your tillage system, but ideally, the
more of it that we put into the organic
matter, which is the living microorganisms,
the non-humic. And then, of course,
the very stable humic compounds that give your
soil the good dark color. And then the more tillage
we do, the more that we’re putting carbon
dioxide into the air. OK, so that’s kind of tying back
to David’s earlier question. Also in the database, we
have soil temperatures or temperatures
that are built in. This is for Otoe
County, which gives us an average temperature
throughout the year. So that’s important
for growth, et cetera. And this is just an example
of keeping it covered. These are about 40
feet apart where we have a good cover crop
cover versus somewhat of a bare soil with a
little bit of residue cover. You have 20 degrees soil
temperature difference. And there’s the reasons
why it’s important. And this graph is awesome,
because it gives you an idea of we can keep
our soil temperatures down there in that green area. It’s much more efficient. Our crops are much
more efficient. Our soil microbes are
much more efficient. More of that moisture is
being used for growth. Our nutrients are
cycling better. In the heat of the summer,
that’s why it’s very important. We get up into that red area,
even our bacteria began to die. And we’re losing more
moisture through evaporation. That’s the bottom line. OK, David, should
I plug on away? I got basically soil
conditioning index to go through yet. Well, we did have a
couple questions there. One, back to the temperature
and the evaporation, is there any way to compare
one system versus the other in the soil temperature that
you might achieve in RUSLE? No. The temperature is
pretty much strictly climate related in
RUSLE2, so it would be important for your growth,
your biomass, and root mass growth. But right now, we
don’t have any way of building that into RUSLE, no. OK and then there was
a question about– you got a lot of interest in your
root biomass production graph– whether you have time to explain
how you got that or maybe you would put together
some instructions that we could work on. I’m not sure how you want
to handle that, Mike. But there was several
questions related to how can they do that back
there at their office? Rather than get into
all the gory details, I will get you something. And it’s very simple. You can get both your
four-inch root mass, and you can get your
total root mass, and also you can break it down
between living and dead root mass. And it might explain how you got
that nifty graph, so if that’s something that you can generate. It’s simply just going
into your vegetation. You click on the folder
for the vegetation. You open it up, and then you
can right click and open, and there’s an
option to View Graph. And it’s fairly simple. OK and then– I figured it out, so– Well, yeah, I won’t
comment on that, Mike. The last thing is again,
does RUSLE in its erosion prediction, does it
factor in just the roots, the impact of having
that root mass in there, and holding the soil, and
all that kind of stuff? Just the four-inch
depth of roots, yes. OK, and one last question. Then I’ll let you go. Is there a difference
between, in salt isobars that are anaerobic or
saturated condition versus non-saturated condition? Now, really it’s
just decay factor that we look at for that. If you have better structure
in your soil, again, you can work with your
soil scientist and use soil with the correct k factor
for the conditions. That would be how you’d
have to work around it. OK, well, I’ll quit asking
questions and let you go on. OK, soil conditioning
index– so this is a neat indicator
for soil health– probably the best
thing we have right now that’s at the field level. This graph here is just
to kind of show you as we start improving
our soil quality, our physical and biological
properties, for example, the other benefits start
occurring before we actually increase soil organic matter. So one of the first things to
improve as we practice our four planning principles is
improve our aggregation and infiltration. And that’s– no
till, for example, that’s one of the benefits
across the board that I’ve seen in some of the– we’ve been
doing some research articles recently. The next thing is your water
and nutrient holding capacity starts to increase and improve. And then as we
move through time, then your productivity
comes along with that. This is a graph that
shows you as we increase, this is in a foot of
soil depth, we go from 0% organic matter up to 3%. We go from 1.1 inches to almost
to 2.5 inches of soil water holding capacity, and
that’s available water. Soil conditioning index–
three items there– we can use that to evaluate our
conservation systems or soil health management
systems that give us the best or improved
soil condition. This directly relates
to our soil health. Also the effects of the system
on organic matter trends, which is really the hub
of soil health. And then we use
three major variables on those trends
in organic matter. Those variables are
the organic material– that would be like your
residues or biomass. And that’s 40% of the model. And then our field
operations, which the more disturbance
we do, the more we break down our residue–
that’s 40% of the formula. And then lastly is our erosion–
as we remove sediment either from sheet and
rill, wind, or even irrigation-induced erosion–
we can build all of those into the model within RUSLE. And that would be
20% of the formula. So the organic
materials– it shows that the formula is used there
and RP is the annual amount of above- and
below-ground biomass. So again, it counts
for our root mass here. And it’s expressed in what’s
called Residue Equivalent Value, REV, which is our
corn residue equivalent. And then also we
can predict how much we need to maintain the existing
level of soil organic matter, which is called the
maintenance amount of REV. And you just see some examples
here of some screenshots. OK, to compare the
climates and how much residue corn equivalent
or what they call REV, residue equivalent values–
you can compare, for example, Raleigh, North Carolina
is almost 6,000 pounds. You’ve got a little
warmer, moister climate compared to Las Vegas. That’s a very dry climate. It’s about three times as much. And you see how
Lincoln compares. Renner, Texas is listed
there because that’s the research that it’s based
on is the equivalent amount in Renner, Texas. OK, so the field
operation component accounts for the operation,
so the more tillage we do, the quicker we’re going
to break down our residue. This is from that same
field study the Dave Lightle and I were at. We had a farmer
running a, basically, a roto-till tool there. And again, we account
for all forms of erosion. We’ve got a center
pivot on a steep hill, so we can account for
irrigation, sheet and rill, and wind erosion. This is just a screenshot that
Linda Scheffe provided me. And on that screenshot,
the new version will have– the SCI value will
show up in red, and red is bad. So if we have a
negative 0.2 or less, that means we’re losing
soil organic matter, and our soil quality
is going down. If it’s green, it means it’s
above 0.2, so it’s positive. It’s going in the
right direction. If it’s yellow, it’s in between. And the values aren’t as
accurate in that yellow range. We had some biomass for ethanol
production wanting to come in, or various other
uses for biomass to remove corn residues
after fall harvest. So we ran– I worked
with my GIS specialist in accounting and
in central Nebraska. Here you can see the HEL. The yellow and red
are basically HEL for Platte County, Nebraska. And then we used
the GIS and used the SCI to run the
entire county with different cropping systems. And here we’ve got a steeper
slope, Nora-Crofton soil, continuous corn, corn-soybeans,
continuous corn that’s irrigated so we
have higher yields, and we have a corn-soybeans
that are irrigated. And these are all
mulch tillage systems. So we’re doing mulch
tillage, and you can see that the only one that
had somewhat of a positive SCI, with removing 50% of the corn
stover the year we have corn is the continuous corn
irrigated scenario. OK, this shows you
graphically depicting– now, we ran various
systems with mulch till, no till, continuous corn,
irrigated dry land yields, and you see all the
red area showing up with the corn-soybean
mulch till system. That’s to be expected. Even a mulch till system
without removing the residue is probably going to show up
in the red or negative area. Here’s one that looks a little
better where we, instead of mulch till,
we’re doing no till. We’ve got some areas
that have a low risk. However, I would say with
almost any of these systems, that a corn-soybean system
really was not sustainable. Continuous corn, however, was
in certain flatter fields. OK, about done with
my slides, David. I put this up here just
to show time variable K. So you can take a look. We’ve got California, South
Dakota, Massachusetts, and Tennessee. So you see how, if we’ve
got a base value of K which is looking at permeability or
soil structure organic matter, all go into the nomograph to
build your K factor that you pull out of your
[INAUDIBLE] database. So it varies
throughout the year. In South Dakota, early in
the year it’s very small, versus you get in the middle
of the year, it’s much higher. So it’s just something to be
aware of as far as keeping it covered. Your soil conditions, your
structure, all those things important to soil
health will vary depending on the area of
the country you’re in. Some of the things that are
being worked on with K factor– Linda and Giulio and
others are working with ARS to improve the K erodability
prediction for a higher clay organic and other soils. Some of those, they’re not
as comfortable with how they fall out, so they need a
little more work and research. Also, we’ve been
you’ve heard the term DSP, which is dynamic
soil properties. We’ve got some projects going
on that we’re working here at the center, and others
are working on, the CIG, to predict the impact that
management has– these four planning principles– on
dynamic properties, which are things like
infiltration, structure, organic matter, and
erodability factors. Also we are working
with Joel Poore and others to do RUSLE and
wind erosion prediction system runs, to also aid
in that evaluation on those impacts of systems. David, that’s my last slide. So I’m about a minute over, so
if there’s any last questions? OK, first, Mike, I just
really appreciate it. It’s been really informative. And we do have a
couple questions here, and then I’ll sign off. There’s a new piece of
equipment comes out, such as a lot of
these vertical tills, or I’ve got a question here
about different corn heads, chopping head versus
a stripper head. How do those tools
enter in or who does the work to get that
data incorporated into RUSLE? The basic process is, with
that they should probably work through their SRC
or State Agronomist, and make sure that they have the
field operations in the RUSLE2 database. And then they would feed that
on up to Linda and Julio, and they’d make sure that they
get that in their database. For example, a stripper
header is a good example. We use that for
small grain harvest, and that leaves very
tall stubble, which is very important, as I talked
about earlier for keeping cool soil temperatures and
reducing moisture loss, versus something
like a rotary combine that brings everything
through the combine, chops it up into small pieces. That’s going to have
smaller residue, and as it hits the
soil, it’s going to break down much quicker. So that impacts your keeping
it covered, keeping your soil temperatures down, and all those
principles we talked about. OK and one last question–
it’s related to organic matter. So soil conditioning
index doesn’t necessarily predict an increase of organic
matter over time, correct? Well, if you have a positive– I
didn’t get into that that much, but that soil
conditioning index is based on various
studies and the impact that management systems
have on soil organic matter. So yes, it does. If you have a very positive
or higher SCI, what they’re predicting is yes, there will be
an increase in organic matter. To say exactly how
much that will be– I don’t think it does that. But the higher the
SCI, the more likely you are to have an increase
in soil organic matter. That’s the premise
that it’s built on. Maybe in the future, as we
incorporate these dynamic soil properties, that’s something
that could come down the road to help substantiate some
of the– when you hear some of these claims that farmers
are increasing it a 10, 15 hundredths of
a percent a year, which would be great to have
a tool to help support that. So OK, Michael. Again, I really
appreciate your effort. I learned a lot. Hopefully everybody else did. We had a huge crowd out there. I appreciate
everybody joining in. Again, thank you Mike for
your excellent presentation. I want to remind folks
of two things– one, if you want your credits,
go back to the beginning and do what Holli
told you to do. I don’t get credits, so I
don’t remember the process. And the second thing is we
are next in this soil health series. It will be on June
the 10th, and we’re going to have a farmer
from the Piedmont region of the southeast
discuss managing soil health and improving soil health
conditions in these very tough conditions down here
in the southeast. So be sure to join
us at 2 o’clock then. And again, Mike,
I appreciate that. And people can get a copy
of your presentations off of the Science and
Technology Training Library if they so choose to. So with that, I’ll
call it a day. Thanks a bunch.


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