[INAUDIBLE]
OK, I'm Rhonda Miller.
I'm going to be talking about manure and compost management
and specifically, what we need to do to make sure
that we utilize those nutrients, beneficially, and avoid
any negative environmental impacts.
So first off, our manure and compost, really,
are wonderful resources and can really help our soil, in Utah,
especially.
And we all know that it contains our nutrients
that we need, the nitrogen, phosphorus, and potassium.
It also contains a lot of micronutrients.
But where it really helps our soil, much more than just
our inorganic fertilizers that we can add,
is that it adds organic matter.
And that helps improve the cation and anion exchange
capacity of our soil, which basically gives it
extra little binding in sites to hang on to more nutrients.
And ultimately, that helps improve the water and nutrient
holding capacity of that soil.
So it becomes like a sponge that can hold even more water
and more nutrients, which then, lets your plant access more
nutrients and water in terms in-- when you have
adverse conditions since that makes
your plants more resilient.
There are some potential negative concerns
to manure and compost.
If we don't manage them correctly,
if we let them run off from the field,
especially if it gets into a water source,
we can get a lot of algae growth from those extra nutrients,
which what's called eutrophication, that can
be harmful to the aquatic life.
Even if we keep those nutrients on the field,
if we over-apply manure or compost,
we can create some really negative impacts
to the groundwater.
In the San Joaquin Valley in California
is a good example of this.
They have over-applied manure for decades,
and now they've gotten to the point where they've actually
increased the nitrate level in the groundwater supply
to where it no longer meets EPA'S drinking water standards.
They have, from the bottom of that red zone
to where it actually gets to the groundwater, years,
probably, decades, worth of nitrates that will continue
to move down that soil profile and continue
to impact their groundwater.
So it's really important that we manage our nutrients
appropriately.
And from a personal standpoint, from a farming standpoint,
those nutrients that you've applied out there,
you've already paid for them.
You've spent the energy and the effort
to get those nutrients out to the field.
If you let them volatilized, or leached, or runoff,
you're losing those nutrients.
And those are nutrients that your plants
could have utilized.
And in most cases, you're going to have
to probably buy commercial fertilizer to replace that.
And so, it really is advantageous to try and utilize
those nutrients well.
So how do we do that?
First thing we need to make sure that we actually know
what we're applying and doing.
So we need to test our manure.
They recommend that you test it annually
and as close to the application time as possible.
Manure does emit ammonia and so, we're
losing nitrogen as it sits.
We should be testing our soil annually
for the crops that need nitrogen and a minimum of every three
years for the crops that need only phosphorus.
So like alfalfa that produces its own nitrogen,
you would probably only test that soil every three years.
We then, need to look at what our crop needs are.
We should look at our crop rotation
and determine what crop are going to grow.
Look at the average good yields for our area or what we can do.
This shouldn't be your maximum yield possible,
but a really good average yield.
And determine how many nutrients it
takes to grow what that expected or yield goal is.
So if you were shooting for 25 tons of silage per acre,
you would then determine how many
nutrients, how much nitrogen, phosphorus,
and potassium is needed to grow that crop.
I've listed a couple of resources there.
There's a link at the end of this presentation that
will provide you links to all of those resources, if you want.
Again, you should use average yields.
And then, we need to take a look at what we've done before.
So if you've had alfalfa in the field previously,
alfalfa and any of those legumes,
actually leave nitrogen in the field
when you terminate that crop.
Alfalfa, depending on the stand, can leave anywhere--
have anywhere from 40 to 150 pounds of nitrogen per acre
available for your next crop and even in the second year,
from 0 to 75 pounds of nitrogen per acre.
So you really need to look at what's
out there, and what you've grown before,
and account for those that nitrogen that's there.
We also need to look at what our previous manure
and compost applications were.
So manure actually has two primary forms
of nitrogen, the ammonium nitrogen,
which is an inorganic form.
That's readily available to the plants right away.
And an organic form of nitrogen.
That's nitrogen that's tied up in proteins in organic matter.
The organic nitrogen actually requires
microbes to break it down.
And so that's a slower process.
It's a process called mineralization
and that will vary based on the soil type, the organic matter,
the moisture, and temperature, especially of the soil.
So as we start looking at that, you're going to--
we want to make sure that we're accounting for the manure
and compost that we've applied before.
So manure-- in the first year for like dairy manure,
you could expect it about 55% of the total nitrogen
would be available and 30% in the second year,
and then decreasing amounts in those following years.
If you apply poultry litter, you can
expect that probably about 75% of that nitrogen
will be available in the first year.
So it will vary based on the type of the manure
and then your specific conditions, the moisture
and temperature.
These some good starting points are
available in the resources listed.
And then we'll want to look at our actual application rates.
We know how much additional nitrogen and phosphorus
we're going to need to grow our crops.
We need to decide then if we want to apply manure,
based on the nitrogen needs of the plant or the phosphorus
needs.
If we apply manure based on the phosphorus needs,
we may need to add additional nitrogen fertilizer,
because manure and compost have proportionately more phosphorus
than nitrogen compared to what the plant needs.
We also then actually need to go look at our soil test levels.
In the West, we typically use the Olsen method.
And for that, if our soil test comes back
between 0 and 50 parts per million,
we can apply our manure compost based
on either the nitrogen or the phosphorus needs of the plant.
If we're at 50 parts per million to 100 parts per million,
we should only be applying manure compost
based on the phosphorus needs of the plant.
That's because we already have way more
phosphorus in that soil than what our plant actually
really needs.
We're now trying to prevent negative environmental impacts
from that phosphorus.
Too much phosphorus in the soil can actually
bind up all the sites and then leach
and you have further much greater risk of runoff which
contributes to eutrophication.
And if you're soil test level's over 100 parts per million,
that's really a drop dead.
You should not be applying any more manure to that field.
Now, as we know how much we should apply, part of it
is actually making sure that we're
applying what we think we are.
So it is really quite important to calibrate your equipment
every year and make sure that what you think you are applying
is really, truly what you're putting out in the field.
If we are looking at compost, compost
has a couple other things to consider.
Compost, in general, has a little bit higher salt content.
It varies a lot.
It can be fairly low to fairly high.
We measure that salt content by electrical conductivity
or measurement called, EC.
And if we have a saline or sodic soil,
we might want to look further at that, because we don't want
to be adding a lot of salts to the saline and sodic soils,
especially if those salts are from sodium.
So the salts that can produce the high EC
levels or the salinity in the compost,
can be either sodium salts or they
can be from like potassium, or magnesium, or calcium salts.
It's an issue if primarily the salts are from sodium,
because that actually can help destructure the soil
aggregates.
If it's potassium, calcium, or magnesium,
those actually are not really a problem.
We can determine that based on the sodium adsorption ratio
test and that will help give you that ratio of sodium
to the other cations.
If it's a high ratio of sodium, hence, then you
may want to be limiting the amount of compost.
Even with some of that, adding some compost
can still be really good.
In many cases, that organic matter
helps alleviate some of the other problems that are
characteristic of these soils.
But if you have saline or sodic soils
that may warrant a little bit more attention.
We then need to look at how and when to apply the manure.
Timing is really critical.
They recommend that you don't apply manure within the 24
hours before a big storm event.
We really should be avoiding application
of manure onto saturated, frozen, or snow-covered ground
if any runoff is possible at all.
If it's a low risk as determined by-- in Utah
we use the UMARI, Utah Manure Application Risk
index to determine if it's low risk or higher.
But if it's higher than low risk,
basically no runoff is possible, then
we should not be applying during the winter.
If you want help with UMARI, you can do it yourself,
but NRCS can help determine those calculations really
easily for you.
And incorporating is really important.
That's actually one of the key ways
we can help maintain and retain a lot of those nutrients.
Utah guidelines say, we should incorporate that manure
within three days.
But really, you want to incorporate that manure
just as quickly as possible.
Again, we'll go back to that our manure is ammonium nitrogen
and organic nitrogen. That ammonium
nitrogen rapidly converts to ammonia
and is lost very easily.
At a study that we conducted at USU,
we lost 50% of the ammonium nitrogen
within the first 24 hours, 76% within the first 48 hours.
So if you waited for three days, you've
lost most of that ammonium nitrogen.
You'll still have the organic nitrogen,
but you're losing a lot of your nitrogen that's right there.
If you incorporated that nitrogen,
ammonium binds to the soil particles
and you greatly reduce the ammonia molasses.
So incorporation very rapidly after application,
can help reduce your volatilization losses
by about 70%.
If you look at this graph on this right on this slide,
you'll note that we actually looked at a study
where we had manure that had bedding or straw with it
and the manure that was from a flushed dairy--
stall dairy where we were using sand bedding so you weren't
having that carbon source.
Manure with a carbon source, such a straw,
has a much lower emission rate of ammonia than manure
without any bedding in it.
And that's that, because that carbon can help
and the microbes can help bind with that nitrogen
and bind it up rather than letting it be converted
to ammonia and volatilize off.
So bottom line, immediate incorporation really
can help save a lot of nitrogen. If you
can have one person applying manure
and another person going, basically,
right behind him incorporating it, that's your best.
It's saving a lot of that nitrogen from volatilizing,
and that is nitrogen that can be used by your plants,
and reduce the need for commercial fertilizer.
And last but not least, we should
be looking at other land management practices that
help reduce any runoff.
If your field is next to a waterway, or even
a canal, or a ditch, you should be
having some setback or buffer zones as you apply manure.
If you're right next to a waterway,
they recommend a 100-foot buffer from the waterway
to where you last apply manure.
So you can still apply your commercial fertilizer,
but they are recommending that you don't apply manure
on that down gradient edge next to the waterway.
Another option, rather than the buffer zone,
is to use a vegetative filter strip, that
would be like a strip of grass or some other vegetation that
can help trap any of those nutrients
and manure that may get to those edges.
And they generally recommend about a 35-foot wide vegetative
filter strip.
So bottom line, manure is a wonderful resource.
The key is that we need to apply that manure so
that the nutrients are utilized in a beneficial manner
not a negative manner.
We do that by testing the soil and manure,
determining the crop needs, adjusting
for the previous legume crops, previous manure
applications, and the soil saltiest phosphorus levels.
And then things that you can do, incorporate as fast as possible
will maintain as much of your nitrogen as you can
and use those management practices that
help reduce runoff.
So with that, I'd like to thank you for your time.
Resources can be found at that website and then
that has links to the different resources that I've mentioned.
And if you have any questions, I'd be happy to help you.
Thank you.