My background is kind of a combo of horticulture and specialty crops
And soil. My master's in soil science and then my Ph.D. was in agroecology looking at different soil management practices for strawberry production.
So today I'm gonna kind of take a big picture view of what is soil health and then emphasize why
we do want to continue to use composting and organic amendments that cover crops because they support soil health.
All right, so first up, I think it's important to think about what the soil does for us,
because I think very often we think of the soil as just being some broken down rocks that are underneath our feet.
It's just kind of holding trees and plants in place. But there's actually a lot of really important functions that the soil does.
Once we start to realize all of these functions,
that the soil is providing humanity and the ecosystem, then we can start to think about how do we protect these functions and protect soil as a resource.
And so back in 2015, there was a really big push by the FAAO to acknowledge soil health.
And actually in 2015, it was the international year of the soil.
And so there's a lot of really great resources out there that you can find there
Just talk about all of the different functions of the soil. And I really like this one because, you know, from an agricultural perspective,
we focus a lot on what does the soil do to help us grow food, fiber and fuel.
But the soil is also doing other things like carbon sequestration, it's helping with water purification, it's helping with climate regulation.
Nutrient cycling, habitat for organisms, helps with flood regulation and mitigation, etc.
So there's all these different things that we start to think about the soil is actually doing for us.
So within that context, then we can start to think about, OK, the soil is doing all of these different ecosystem functions for us,
how do we determine if a soil is healthy and able to do those things?
There's a lot of different definitions of what is soil health, and sometimes it's also called soil quality.
I like the idea of health because it helps to think of the soil as something that's a living, breathing thing.
But I like this definition. They say that the capacity of the soil to perform ecosystem functions that support plant growth and biological organisms,
resist erosion and reduce negative impacts of air and water resources is a measure of soil health or soil quality.
So basically what we're trying to do is we're trying to maximize the soil’s ability to function to do these things that we just talked about.
Well, one of the more simple definitions of soil health takes a little bit different perspective and focuses more on how we can manage soil health,
and I think ultimately that's kind of what our goals today is to think about how we impact this.
Doran was a researcher that saw a lot of work on social health.
He took more a perspective of our impact on social health in terms of the soil.
It's not considered healthy if it is made for short term productivity at the expense of future degradation.
And so this starts to bring up this idea of how do we manage social health and why is it so important for agriculture and the like?
So, again, one thing I always try and emphasize to people is that soil is a living,
breathing thing and it is a resource that we use, but it's not a renewable resource, at least not renewable in our life span.
It's estimated that it takes about 100 years to form one inch of topsoil. That every year seventy five billion tons of soil is eroded globally,
two thirds of that coming from agricultural land. And again, there's this big push back in 2015 about the international year of the soil,
and they actually celebrate World Soil Day every day on December 5th.
So we're starting to become more and more aware of why soil
Health is important to ag, this is this resource that we use to grow our food and fiber.
We need to make sure that we're protecting it so that we continue to have it in the future.
One way I think that we can think about soil health more specifically is thinking about the different components of the soil.
So very often if you pull a soil sample and you send it into your lab,
the lab is going to tell you something about the physical and the chemical components of soil health or the soil quality.
So you're going to tell you something about soil pH,
They may tell you something about your soil texture, probably something about the nutrient qualities.
But really there's a third component to the soil and that is the biological component.
So things like nematodes, bacteria, earthworms, et cetera, all also down there in the soil.
Basically, what we want to try and do is make sure that all three of those different components, the physical, the chemical in the biological,
for all in balance, when those are in balance, supporting one another,
that's when we know the soil is going to be able to function and it's going to be healthy.
But one thing I always try to emphasize to people about health is that there's really one
component of the soil that really drives a lot of the other components in one way or another,
impacts the other parts of the soil in one way or another. And that's organic matter.
Organic matter can be things like compost, like manure, broken down leaves, et cetera.
Organic matter, when we put it into the soil, it feeds soil microorganisms, it releases nutrients.
So it's sometimes a chemical component of the soil. It also has physical properties where it helps the soil particles stick together.
So it's impacting the physical components of the soil. It actually can help water infiltration be improved on
Sandy soils or on heavily compacted clay soils.
And so this idea of organic matter being really key to soil health is one of the reasons why we want to talk today about manure compost and cover crops.
But I want to dig into this biological and particularly organic matter side a little bit more,
because this is the part of soil health that I think we're still learning a lot about.
It’s the part that's been researched the least,
but we're starting to find out some really exciting things about what happens when we add organic matter to the soil.
The big things that we do know is that organic matter, when you put it into the soil,
the biggest thing that we're doing is we're feeding microorganisms that live in the soil.
There was a really nice paper that was put out by Science a few years ago that was called The Littlest Farm Hands.
And if you're really into soil health,
I really recommend you read this article cause it's really just a delightful little article about how the farm hands that we should
be focusing on are feeding the soil microbes in our soil and that they're doing the most work for us that we don't even realize.
And they go through all of these different things these microbes are doing in the soil from conferring heat and cold tolerance to plants,
helping plants deal with drought or flooding, helping plants become more resistant to insects or even heavy metal toxicity and the like.
And so this is an area of soil science that’s becoming more and more exciting.
People are starting to think more about how can we get organic matter into the soil to feed it.
So here are some ways that that this can happen,
that we can add organic matter into the soil and it can impact all aspects of the soil, whether it's the biological, physical or chemical.
This is a nice little image from a Building Soils for Better Crops, which is a SARE publication. If
You haven't seen this book, I recommend checking it out as well. It's free from SARE and we always have a few copies of it,
If anyone needs one. It basically goes through and shows you that we're adding organic matter to the soil, we're increasing soil
biological activity, all those microbes are being fed and they're going to start doing their jobs and start reproducing.
And some of the microbes in the soil, their job is to decompose other organic matter that’s in the soil.
And when that happens, they're going to release nutrients. They can also sometimes take harmful substances and detoxify them.
Some of the things that they extrude out into the soil are kind of sticky substances that help the soil particles stick together.
And that's going to increase aggregation and help the soil resist erosion.
It's also going to increase pore size, which can help infiltration and improve overall tilth of the soil.
Also, this increased biological activity of having more microbes active in the soil means
that there's going to be a greater diversity of microbes present in the soil, hopefully.
And that's going to mean that there's going to be more guys that are going to try and eat the bad guys that we might be worried about.
Some things that might be disease causing or pests will have more competition in the soil as well.
And overall, hopefully our goal is, is that all of these different processes are going to lead to healthy plants.
So all of this coming from just adding organic matter into our soil.
So how do we go about adding organic matter in the soil? One way that we can do that is by adding manure.
There's a lot of benefits to manure. We were adding organic matter.
We're adding nutrients, particularly nitrogen, phosphorous, some other micronutrients.
I've missed some of our previous speakers, but thinking about this complete on farm nutrient cycling,
if you have your own livestock on farm, there's a way to use the outputs of those livestock.
In some cases, it could be free. So you're getting some free nutrients to add into your soil. of course, with manure
It does require application, so we need to broadcast it and then typically till it into the soil.
Generally with growers, I focus on using this material pre-plant well in advance of the crop being planted,
and partially that's because of some of our food safety concerns. But also manure sometimes can be very hot.
We've been talking about before and can have a really high salt content and for certain crops,
particularly like strawberries, that can be very sensitive to that salt content.
We also want to be aware of possible seeds present in the material or other pathogens.
One thing I always recommend to people who are trying to use manure and hopefully this has been touched on before,
is trying to get the material tested, particularly if its new source that you're using to know the nutrient content prior to applying it.
Another way that we can build soil health and get that organic matter into the soil is compost.
Compost tends to be, in my mind, a little less risky for several different reasons.
Basically compost, as you all know, is just decomposed, and it's more stable
Organic matter. It’s already broken down, gone through some kind of process. Compost can also add nutrients like manure can, and also add some microbes.
There's been a lot of research done on using compost to create suppressive soils
where you're suppressing disease organisms and promoting good bacteria in the soil.
Of course, if we continue to apply compost, manure or any of these things over time, we can have sustained impacts on increasing soil organic matter.
I always do try and emphasize to people, though, that this is a really long term process.
If you go to compost this year, you're not really going to up the percent organic matter in your soil immediately.
It's going to be something that you'll have to commit to over the long term.
Another thing to keep in mind with compost and comparing it to manure is there's more dry material in compost.
You're kind of getting less bang for your buck or more bang for your buck and applying less water than you would be with manure.
You know, there's a lot of ways to use compost. You can apply prior to bedding and till it into the soil.
We can also use it as a side dress application, either to help suppress weeds or add some nutrients to the soil.
There's a lower chance of high salt content in compost. So there's less chance that you're going to burn your plants.
And if it was composted properly, of course, that reduces the risk of weed seeds and pathogens.
Again, I try to emphasize to growers, make sure you get your compost tested so that you know the nutrient content prior to applying it,
so that maybe you can use it as a nutrient credit to reduce your other fertilizer uses. I do try and emphasize,
though, that depending on your source, it can be more expensive to purchase and to haul or produce yourself.
And then finally, the one that I like the most in terms of building soil health is cover crops,
and I think Karl kind of touched on this in the beginning. And this is really our opportunity to grow our own organic matter in place.
So we're choosing cover crops that can have other benefits to the soil.
We plant them in a fallow period, and we're able to produce our own organic matter,
in some cases our own nitrogen. Because they're not of an animal origin, it’s a pretty low risk.
We can add nutrients as well as provide habitat or food source for microbes there on site.
Another thing that I like about cover crops, particularly if we're using them in a fallow season,
is it's actually actively holding the soil in place because the plants are growing and rooting in.
They're going to hold the soil and that reduces erosion. Particularly here in Arkansas,
where we have very heavy rainfall and have some events where we have the potential to
lose a lot of soil and go back to that idea of how much erosion is happening every year.
Also, for a selective and we choose cover crops that do not, they're not host to nematodes or diseases,
we can help break up some of that disease pressure cycle as well.
And there's also the opportunity to suppress some weeds if we’re planting cover crop in the same season as some of our more aggressive weeds like pigweed.
There's a lot to the how of cover crops, and that's where I would like for you to go look at that link that I sent in the chat.
We have an entire series of videos and presentations on the how, the when, the where, and the why of cover crops.
But generally, we're going to be planting them in the off season and fallow periods.
And, you know, because it is still a crop, even though we're not going to be harvesting and selling,
it does still require a management for seeding and termination in order to maximize the benefits of the cover crop.
Real briefly, I will say that there's kind of three big groups of cover crops that we use,
and those are the grasses, the legumes and the brassicas. Grasses we plant because they produce a lot of biomass.
So they're going to really have an impact on organic matter,
on increasing organic matter. Legumes we plant because they can fix nitrogen out of the atmosphere. And the
brassicas typically we plants because they're going to have some kind of disease suppression capability.
Increasingly, though, I would say most growers are switching to where they're not planting just a single crop and they're
really planting mixes to try and maximize the benefits of all of those different types.
But my biggest recommendation would be to not just focus either on one type of organic
matter addition to your soil and really trying to integrate multiple practices together.
One thing that I recommend to some of our strawberry growers who use cover crops in the
summer is to actually incorporate manure into the soil prior to seeding a cover crop.
And doing that,
they actually increase the amount of time before they're going in with the cash crop or the profit may be at risk from having that manure application.
When they plant the cover, the cover crop will actually take up some of those nutrients as well as it's growing, 155 00:15:58,425 --> 00:16:08,035 So you get a better cover crop stand. You can incorporate cover crop into the soil and then maybe apply some compost as a side dress.
So we're integrating multiple practices in one to try and increase soil organic matter and ultimately soil health.
You have some resources that Karl put in the chat about the sustainable strawberry production guide,
and this is actually pulled from there where we just did some comparisons of
using cover crop and compost actually as substitutes for chemical fertilizer.
So as I said, Karl really set me up perfectly for that question.
We actually compared what would be the cost of using compost and covered crops as your
substitutes for your 60 pounds of nitrogen that you need to pre-plant on strawberries.
And basically, our estimate was that a cover crop to plant and manage,
Costs about hundred fifty dollars an acre and compost cost around two hundred thirty four dollars per acre in our scenario.
And this was done in North Carolina. So the numbers don't quite work out because nitrogen is a lot cheaper than that.
But we also were getting other benefits from using the compost in the cover
crop on yields that we didn't necessarily always see from a chemical fertilizer.
One recommendation I always make to growers, though,
is use soil sampling as a way to monitor how your practices are impacting soil health and nutrients.
We said before you can pull the soil sample and you get some basic information about chemical and physical properties.
You can actually also pull a soil sample and request that they run organic
matter in Arkansas and they will tell you that and you can monitor it over time.
But there's other ways you can also monitor soil health and how different practices are impacting those,
and some of those are just visual things like monitoring for earthworms, changes and soil color particularly at the soil surface,
watching infiltration and the like. And there's some nice resources out there from the Cornell framework that talks about how to monitor soil health.
I will close and again refer you to that resource where we did a cover crop for vegetable production training a few years ago.
There's a lot of nice YouTube videos. And we interviewed Adam Chappell, who is one of our growers here in Arkansas
That uses cover crops a lot and is a big proponent of soil health.
So with that, I'm happy to take any questions, if there are any, and I appreciate, again, the invitation to speak today.