(Soft music)
-: All right.
Hello everyone.
My name is Fernanda Krupek and I'm a PhD student
in the department of Agronomy and Horticulture
and I'm very excited to be here today
and thank you all for joining.
This is a great opportunity to share with you all,
some of the learnings that we are creating
with the UNL and our CSO health initiative,
that we hope you
advance adoption of soil management practices in Nebraska
and today we are going to talk about
the impact of soil management
on multiple soil health indicators,
particularly across soils
with different management history and field testing
of a variety of cover crop management practices.
Before I get you started,
I do want to acknowledge many partners
collaborating in the soil health initiative.
This picture you are seeing here
was taken exactly one year ago in our annual meeting
and we would have taken the same picture today,
if not for the pandemic.
So you are seeing here the team behind our project,
but I also would like to thank
the many extension educators, NRCS' staff
and cooperating farmers that are working with us.
I want to start today with a definition of soil health
to make sure we are on the same page.
So when I'm talking about measuring soil health,
I'm talking about soil's ability to function as a vital,
living ecosystem that sustains plants, animals and humans
and clearly,
water cycling is a big component of soil health,
Right?
This picture you're seeing here
is from one of my first few visits in Knox county May, 2019.
So there is this nice fence lining the Meadow
separating these two different managements
and you can tell that
because of the different vegetation cover,
Right?
So one with residue cover in the right-hand side,
and by the time of the year that this picture was taken ,
you can guess that this feud was left by halo
over the winter time,
as compared to the few on the left hand side
from one of our producers collaborating
that had cover crops.
So we know that has been rainfall
because the water is standing on the top of the soil
on the right-hand side
and if you recall 2019 was a very wet year
with a lot of bloating issues.
So what we are seeing here is one soil
on both sides of a fence line
that have different functional expression
after a rainfall.
So I would say that this soil in the left hand side
is likely healthier
because there is residue covering the soil.
We don't see the evidence of cresting, no water pounding,
no toga occurring, and the crop looks healthy,
right?
As you compare on the right hand side,
it looks like
there's going to be some cross-training happening.
So let's say that this soil is not functioning
with regard to water cycling as we would expect,
but it is all the same soil here
and that's the point I would like to make
is that soil has its context, its inherent capability
and then the way we manage it
and the land use on the top of it
is that function expression of its health.
So I would be glad to know from you now,
some of the soil health management practices
that you have heard about, or you are interested in.
So if you are watching this presentation
from a computer or a projector,
you can use the camera on your cell phone
to scan this QR code and they will take you to the website
to submit your answer
and you can also use your cell phone browser
and go to slido.com and enter the passcode onfarm
and then submit your answer.
Also, feel free to send me more than one answer
as much as you want.
I'll give some time here so you can submit your answer.
Okay,
So you can use the QR code here?
Okay,
We see inter seeding,
Cover crop.
So what you are seeing here is called word cloud
and it is related to the frequency of words
that the audience is still meeting.
So the bigger the size of the letter here
means more people send that answer.
So we feel a lot of interest in cover crops, No-till,
there also a nutrient management.
Okay.
For the sake of time, I'll move ahead,
but it's nice to see that
majority here is interested in cover crops
and that's one thing that I will focus today
on my presentation too.
So thanks first to submit your answer.
So here in Nebraska,
we have the Soil Health Initiative
and this is a statewide
statewide partnership to establish data and monitor changes
in soil properties
through the adoption of conservation practices.
And this project was launched in 2016
and farmers participate in this project
were sign up through equip contracts,
they acquired them to conduct its trip trial,
comparing at least two contrasting soil management practices
for five years .
In terms of data that has been collected
since the beginning of this initiative,
we have cash crop, yield monitor data
or research participation farm
and choose soil health assessments,
One using a feud protocol developed by NRCS
and a Haney test
which is an assessment available in commercial laboratories.
In these two soil health assessments
is what I'm going to focus on my presentation today.
So we are going to look at data
that has been collected in Tenure farm sites.
As you can see in this map here,
the soil health treatment comparisons in each side
was different
as you can see in this list here,
we have single species versus multi-species,
different cash crop rotations.
And one aspect that is often overlooked,
which is the whole that field management history plays
When we are analyzing data from on-farm research.
So in our data set,
for example, across all the sites,
the time of cover crop we use vary
from zero to up to 12 years,
tiller adoption practices vary from zero to up to 30 years
and different plant species on there
in a five-year rotation.
We had feuds from two to up to 18 different species,
So we need to take that field history into account.
And the point I would like to make here
is that the analysis I'm going to show today
is a little bit different from what we are discussing
on the on-farm research results book
because here we are combining results
from multiple farm studies
that were testing cover crop management practices
and taking to account the food history of those times.
So for each side,
we quantify the cash crop diversity ,
frequency of mechanical soil disturbance,
cover crop in organic amendment use
and cropping livestock integration.
Well, you don't need to memorize all these equations,
I'm presenting here,
but the main idea is that each index was defined
to represent a progression
to more intensify cropping systems,
option of soil health management practices
and the greater the index,
that means they hired a number of different plant species
in their rotation,
fewer number of years with power bare soil,
fewer number of years with tillage operation,
increased number of organic amendment application
and more frequent integration with livestock
into their cropping system.
So we applied this classification approach
to 21 indicators of soil,
physical, chemical, and biological health ,
which is in this table here.
In terms of sampling measurement,
all the fields were sample at zero to seeing inch
prior to the start of the experiment
that was in 2016 or 17,
depending on the viewed
and we also collect data in the fall 2019,
and it's quite a lot of measurements,
right?
So what, what do we do?
So basically we have all these measurements
and the first thing we did was
to look at the relationship between all these measurements
and this soil management indexes that we calculated.
So that's what you are seeing here in this graph,
I know there's a lot of information going on,
but let's take a look at it in pieces.
So first this graph is showing us,
we just saw how indicators are more forceful
to differentiate that transition
towards intensified soil management practices.
So for example, soil organic matter ,soil respiration,
infiltration, soil porosity,
water extractable organic carbon ,nitrogen,
and all those properties that I highlighted here,
they were the ones most sensitive to change in cover crop,
crop diversity in organic amendment .
In thermostat cropping livestock integration
in years without soil disturbance,
then we have soil temperature,
volumetric water content, manganese, potassium, phosphorus,
all those properties, they were most forceful
to differentiate the change on those management practices.
Another information we can get from this graph here
is that soil health indicators,
they were found to be either positively or negatively
related to the different management indexes
and that's the meaning of the errors
going here in the opposite direction.
So for example,
as we increase cover crop use,
there is a decrease,
We see a decreasing bulk density, which is good,
right?
But let's look at here
as cropping livestock integration in years
without soil disturbance increase,
we see potassium, inorganic nitrogen,
all those properties here going in the opposite direction.
And yeah,
that's the meaning of it going on different directions.
And the point I would like to make here is for you
to think about the big picture
and the visual analogy I would like to make is
when we are trying different management practices
to improve soil health, it is like climbing a mountain,
right?
There will be ups and downs,
but it is important to think on the big picture
and the longterm goal in reversing soil degradation.
Our next step on the analysis was to model
the relationship between management indexes,
to all together with the soil properties,
to understand the management importance
on the soil health indicators.
And this is what this graph is showing in here,
their relative importance of each management index
on modeling their response of the soil health indicators.
So for example,
with soil properties that are closely related
to carbon and nitrogen dynamics,
such as soil respiration, organic matter,
water extractable carbon nitrogen, total nitrogen,
we can see that their cover crop use
explained quite a lot of the total variability in our model.
In terms of crop diversity index, for example,
we can see their soil water infiltration
and problematic water content
was the highest per crop diversity index
and when we average across all this soil health indicators,
we can see their cover crop use was the most important
and contributed to up to 30% of the overall influence
in all the assessed variables followed by years
with outside of disturbance, cropping livestock,
organic amendment and crop diversity.
So if we consider, all these indexes keeping mind
that their cover crop use is the only one
that shares these critical features
of continue living hover and roots in the soil
with the use of cover crop.
And because Cover crop was the most important management
affecting properties related to carbon nitrogen dynamics.
Now we are going to look at the impact of cover crops
on Haney task calculations of available plant nitrogen,
nitrogen recommendation, nitrogen savings.
So let's focus on this first graph here .
Here we see this linear relationship
between soil respiration on the horizontal axis
and organic nitrogen on the vertical axis
and this organic nitrogen release here
is an overall credit that the Haney test calculate
from the soil that other more conventional fertility tests
that utilize nitrate or ammonium did not account for
and because organic nitrogen needs in the amount
where needs through a microbial activity
from organic nitrogen pools.
Typically this value increase as the systems gets healthier.
And
as we can see here,
we have organic nitrogen release
was highly associated with soil respiration
and this is already expected
because the Haney test uses soil respiration
as one of the variables
to calculate the organic nitrogen we need .
But the point I would like to call your attention here
is the fact that intensification in cover crop use,
which is represented here
by these larger and lighter blue cycles,
those resulted in greater 24 hour respiration
and organic nitrogen release.
And remember,
I mentioned at the beginning of this presentation,
that the time of cover crop use
among our farmers vary from zero to up to 12 years.
So these last two indexes here represents
feuding adopter Cover crops for over eight years.
We also have here their relationship
between plant available nitrogen
and organic nitrogen release.
There was found to be negatively correlated
to corn and wheat nitrogen recommendation.
And we , in our analysis,
we found that in healthy and high functioning
biologically active soils,
particularly those using cover crops for over eight years,
this nitrogen credits could be above 10 PPM
and that reduce the nitrogen fertility substantially.
And what does that mean in terms of nitrogen savings?
So we can see that fields adopting cover crop
for a long time,
they have an average savings of $44 per Hector,
which would be around $18 per acre in nitrogen application.
We choose significantly higher than in fields
with less intensification in cover crop use.
So taking together all of these results
and it suggested that longterm cover cropping is trending
to low nitrogen requirements and higher nitrogen savings.
And this is the last graph I would show here
showing the percentage of change from the baseline samples.
Let's focus on infiltration and bulk density.
If we look at the, all the data set,
we don't see difference in changes
because all these,
these virus here are crossing the zero,
but we see that the fields
where we have a no cover crop use
those fields have a decrease in infiltration
and increase invoke density.
So to wrap up my presentation,
I would do like to point out
that intensification in soil management
affect all the soil properties,
but cover crop use was the most important management
that also reduced nitrogen credits
in intensifier cropping systems
and also showing improvement in soil biology
in overall soil health score.
So if you have any questions,
I'll be glad to chat and feel free to contact me.
My email is available here
and Laura, I will turn over back to you.
(soft music)