THE MICROBIOME SUMMIT : The New Path to Health

Ecological Farming & A Perspective on Organics

Dr. Sarah Hargreaves, PhD

Three Ridges Ecological Farm

Overview
Transcript

Overview

Microbes have been around for 3.5 billion years, long before human life. Dr. Sarah Hargreaves is an ecological farmer who studies the interactions between microbes and the soil. In this interview, Dr. Sarah Hargreaves offers a beginner’s guide to ecological farming. This approach to farming looks to maintain important ecosystems in food production and preserve the nutritional quality of the soil. You will learn about why perennial plants are so important to the health of soil microbes. Dr. Hargreaves also offers us some insights into organics, as well as some practical advice on how to be an ecological farmer at home.

Transcript

Tracey:
We’re here today wiith Dr. Sarah Hargreaves. You have your PhD in soil microbial ecology, and you have recently left academia to start your own farm, an ecological farm. Can you tell us about your PhD work?
Sarah:
I’m a soil microbial ecologist, and as an ecologist I study the interactions between organisms, and the interactions between organisms and their environment. And so translating that to microbes means I study the interactions between microbes in the soil and the interactions between microbes and the soil, the soil matrix which includes plant roots and soil particles. And so, I began to think a lot about ecosystems that I wanted to study and apply my knowledge to, and agricultural ecosystems really stood out to me because of the problems that we’re having in agriculture right now, and a lot of them are to do with the soil and how we’ve treated the soil, and how the microbes in the soil and agricultural ecosystems aren’t functioning properly, and this is leading to leaking nitrates in our water and lots of greenhouse gases in our air.
Tracey:
Very interesting. So these microbes play a very important role in our lives.
Sarah:
They do, yeah. We can’t see them, but they’re so critical to the health of our soil, and therefore the health of our plants and the health, ultimately, of our atmosphere.
Tracey:
Tell us a bit about your farming, now. What kind of a farm is an ecological farm?
Sarah:
We think a lot about microbes, and the base of our farming is to encourage the microbes to build healthy soil, to regenerate the soil, because we know that if we have soil rich in organic matter, and a diversity of soil microbes, that it will grow the healthiest, most productive crops for us.
Tracey:
How do you know if you have a large diversity of microbes in your soil? You can’t see it.
Sarah:
You can’t see it. So, what I learned in my PhD is that plants and microbes interact, and it’s that interaction between plants and microbes that’s really critical to a healthy microbial community and a healthy soil. And so perennial species, plant species that live year long, really are helpful to microbes because they provide food for microbes year round, and plants are microbial food. Perennial species allow microbes to eat all year round because of the roots in the ground, and they also allow microbes to wake up at the exact right moment to capture nutrients that are running off as the soil melts, and to start interacting with the plants, and helping plants grow as soon as the growing season starts in the spring. And so the goal of our farm is to incorporate perennial species back on the land by growing perennial pastures. We have native warm-season prairie that we’re going to reestablish, and also cool-season grazing pasture, and we’re planting hundreds of trees. And so, it’s really these interactions below ground, that we can’t see, that we’re promoting by planting perennial species. And then we’re also integrating animals back on the land. So, we have cows and chickens and ducks and pigs, and maybe some sheep in the future, and what they do is they interact with the grass, they graze the grass, and that stimulates the roots, to slough off root material and by doing that it’s creating sugars for the microbes to eat, and it’s inviting the microbes to be active. It’s basically saying, “Okay, dinner’s served.”
Tracey:
A buffet dinner.
Sarah:
A buffet dinner, right, of a diversity of nutrients that the microbes need to function in a healthy way.
Tracey:
Right, and they need a buffet of food to have their diversity, which is so important for our soil and our plants and then, ultimately, us.
Sarah:
Right. Just like your favourite food is different than my food, microbes have different foods, and so we need lots of different plants exuding different types of sugars, having different chemistry in their leaves, and growing at different rates throughout the year, to entice a diversity of microbes in the soil, so that means that, at any given time, there are microbes doing their jobs in the soil, because there’s a diversity of food.
Tracey:
Right, and they are working hard for us.
Sarah:
They are. They’re working really hard for us, even in the winter. And even when we treat our soil poorly, the microbes are still there, working. They’re just not working as hard as they can be, so when microbes work really hard we are able to store carbon in the soil.
Tracey:
Can you tell me a little bit more about these microbes?
Sarah:
Well, when I talk about microbes, yeah, it’s one word. But it actually—I’m talking about the majority of diversity on life. It’s astounding. If you were to look at the tree of life, there are three domains: there’s the bacteria, the archaea, and the eukaryotes. And microbes are single-celled organisms; they’re all of the organisms in the domain bacteria, all of the organisms in the domain archaea, and then they’re also in one kingdom, in eukaryotes, the fungi. So, we are also in a kingdom, the mammals are in a kingdom, in eukaryotes. So we, as humans, are this tiny little arm in the tree of life, and microbes are the vast majority of the diversity.
Tracey:
How long have microbes been around?
Sarah:
Yeah, it’s fascinating. There’s this great quote by Stephen Jay Gould, an evolutionary biologist, and he says something along the lines of, “The age of dinosaurs, the age of mammals, and the age of man pale in comparison to the age of microbes that have been around for 3.5 billion years.” You know, they were here when it all began, and they’ve been evolving. So, there’s a lot of genetic diversity, and there’s a lot of functional diversity, and it’s this functional diversity that we care about. It’s what they do in the soil that we care about, and that they can do it in such amazing combinations, and it’s what they do in our gut that we care about.
Tracey:
Like the microbes that are in the soil, are they the same ones that are in me?
Sarah:
That’s a great question, and it’s not my area of expertise, but we do know that the soil is a reservoir of microbial diversity, and that there is transfer between the soil and humans. We also know that many of the bacteria that live in the soil are common to our gut. The gut is more anaerobic, so there’s less oxygen in the gut than there can be in healthy soil, so there’s differences there. But they’re the same type of microbes, same type of bacteria, in the soil and in the gut, and then there’s just specialized versions of that bacteria that live in soils and specialized versions that live in the gut, but they’re all digesting.
Tracey:
Which help us, these microbes.
Sarah:
Yeah, it releases nutrients.
Tracey:
I think that that is so important for all of us to understand. Is that the microbes that are in our soil could be similar to the microbes that are in us and they are helping us to digest food better.
Sarah:
Yes they are and they are helping to make the plants we eat healthier and the animals we eat healthier in a lot of ways too. It’s that connection.
Tracey:
How can we keep our soil microbes really happy?
Sarah:
There’s a lot of research that’s gone into this in the last few years, and what the research is telling us is that it’s all about diversity. A healthy microbial community is a diverse community, and that’s because it’s resilient to disturbances like drought, or resilient to disturbances like illness in our body, and that it can recover quickly from disturbances because there’s always a bacteria there, or a fungi there, to take advantage of the situation. You’re not dominated by bad bacteria. So you want a diversity, and we know that diversity of microbes in the soil is really facilitated by a diversity of plants above, and that’s because of that buffet.
Tracey:
In your PhD work, did you learn how to care take for these microbes? They’ve been around for 3.5 billion years, do they need us?
Sarah:
Yeah, they do, and especially in managed ecosystems like agricultural ecosystems. So what I learned in my PhD is the importance of those plant-microbe interactions, and how a lot of current farming practices ignore those interactions and instead use fertilizers or chemicals to replace the microbial functions. And so, what we’re doing on our farm is we’re bringing the ecology back to agriculture, trying to bring ecology back to agriculture, by promoting interactions, by planting perennial species that will be there year round for microbes to interact with, will have roots for microbes to interact with, and then really hoping that that will be enough for the microbes and the plants to take care of themselves. But we need to give the microbes their food back. What studies are showing is that long rotations, so three or four years, gives the microbes the diversity they need to reawaken in the soil and start processing soil organic matter, and creating healthy soil.
Tracey:
Right. So, do farmers have enough information, now, to fully understand how to care take for the microbes, or is there ongoing research? You’re part of a program called the Farmer-led Research Program. Can you tell us about what’s going on, there?
Sarah:
Yeah. I couldn’t completely leave academia. I love research too much, so I work with the Ecological Farmers Association Of Ontario, on their new program the Farmer-led Research Program, and what I do is I train and support farmers in Ontario to conduct research on their farm, replicated and randomized, rigorous research trials on the questions that they want answered, so that they can innovate efficiently, and become better stewards of the land, better farmers, more profitable farmers, and more sustainable farmers. And so it’s bringing research to the farm as a really powerful tool for the farmer.
Tracey:
Can you give us a bit of a historical lesson, here, on how we study microbes, and how, in the last ten years, we have accelerated that exponentially.
Sarah:
Yeah, it’s been a really exciting time, and I just happened to start my PhD when this was all happening, so I really lucked out in that regard. This boom in technology that’s allowed us to really start to investigate microbes—so previously, for decades, for centuries, we’ve been culturing microbes. We’ve been growing them in the lab on petri dishes and in tubes, but the vast majority of microbes can’t be grown in the lab. We don’t know what conditions they need, or the conditions they need are so obscure we can’t replicate them in the lab. But in the 90s a technology was developed that allows us to generate DNA sequences, many, many of them, and very quickly and very affordably. So, in the mid-2000s this was adopted by the research community, and the microbial research community, both human health and soil ecology, really took hold of this technology in realizing the power of it for microbes, because now, all of a sudden we can get millions and millions of sequences affordably out of the soil.
Tracey:
What is the most pressing question that farmers want answered?
Sarah:
I think one of the biggest questions right now is: Is it about soil health, and is it about the biology of the soil? And how to track changes in soil health, and how to measure changes in soil health. From my work talking to farmers in the States, in the Midwest, and here in Ontario, there’s a common theme around soil health. Farmers want to know what practices can they do to increase soil health or maintain soil health. And a lot of the methods available to farmers actually measure the function of microbes, so they’re measuring the enzyme activity, or the carbon dioxide that the microbes give off from the soil. Other measurements that researchers use is measuring the DNA of microbes in the soil. So you can actually take a little bit of soil from an ecosystem, bring it into the lab. In just a few hours you’ll be able to see a DNA pellet of the microbes that lived in that soil.
Tracey:
So, now that we know all of this in the last ten years, should we start changing and thinking about our soil and our farming differently?
Sarah:
Yeah, I think thinking about microbes and thinking about how they can work for us to produce healthy crops is a new way of farming. Previously, by adding lots of fertilizer and chemicals to the soil, we’re taking over – those products take over the job of the microbe, and they actually end up degrading the soil. So if we can regenerate the soil and then have the microbes start working for us again, then we actually have a highly functioning, profitable, in many cases as profitable, if not more profitable than the old system, and much more environmentally friendly. One that is storing carbon, reducing leaking into our waterways.
Tracey:
It sounds like farmers have a huge responsibility. I mean, we have this pressing issue of the world. We’re soon to be 9 billion people, farmers have to feed us. Can they do that with the type of farming that you’re talking about?
Sarah:
Yeah, that’s such a great question, and it saddens me now that we’ve set up a paradigm, that we think that the industrial system or the current system is the only way to feed the world, and I actually wholeheartedly disagree with that, and I think the research is pointing towards disagreeing with that as well, because of the importance of diversity and the lack of that diversity, the lack of livestock on the land integrated with crops, and the importance of that integration. And so, moving forward, farming practices that are regenerative, and then sustainable, are those that take advantage of diversity and integrated livestock, and I think that, ultimately, we can’t feed the world with degraded soil.
Tracey:
Right, that makes sense.
Sarah:
And so we need to take care of our soil, so it can take care of us.
Tracey:
Such a great point. I think that that is so important and learning about – and you can speak to some of the research, but learning about how these microbes make our food healthier as well. It’s not just about taking care of them, but they take care of our food to make it more nutritious for us.
Sarah:
They do, yeah. So, microbes are the gut of the world, and they’re also the gut of the plant. And so, at the root, it’s called the rhizosphere, the intimate interactions that microbes have with plant roots. And it’s there that microbes are really excreting these digestive enzymes and digesting food for plants. And what the plants do is they trade. It’s like a market. The plants are excreting sugars through their roots, they’re sloughing off fine roots, they’re giving microbes carbon. And in trade for that, the microbes are releasing these nutrients that the plants can take up, and there’s some research to show that plants can actually signal the microbes for specific nutrients.
Tracey:
Wow.
Sarah:
So, it’s a real dance underneath the soil. You know, “I need this right now, I need a little bit of phosphorus, here’s some carbon. It’s dinner time, give me your phosphorus.”
Tracey:
They have a whole language, the plants and the microbes, between themselves.
Sarah:
They’re hugely networked. And so, practices such as tillage end up destroying these networks, end up destroying the fungal networks, you know, literally, physically ripping them apart. And we forget that the plant is more than just a plant. It’s a microbiome, just like how our bodies are mostly microbial cells. You know, a plant is interacting with the microbes in the soil in order to live a healthy life, and research has shown that the nutritional quality of crop plants over the decades has gone down. We don’t know why this is, there are just correlative studies at this point, but I think it’s a reasonable hypothesis to say it has to do with soil health, it has to do with depletion of the soil, and the lack of interaction, so microbes maybe aren’t there and aren’t there to give the plants the nutrients they want. And also, the nutrients might not actually be there for the microbes to release. If the soil’s so depleted, there might not be anything for the microbes to offer.
Tracey:
So we could be potentially growing food that is nutrient poor.
Sarah:
Correct. It may look like a red pepper but it may not be the red pepper of the past.
Tracey:
There’s a movement, now. People want to be in their backyards, and they want to garden, and they want to grow their own nutritious food. How would they do that, where would they start?
Sarah:
You want to be thinking about perennial plants. So, a tree, and having that tree be the basis for what you’re planting around it. There are a lot of – we don’t think chives are perennial, sorrel is perennial, you can get perennial onions, actually, and then you can plant annuals around that. And so it’s sort of thinking outside the box of linear lines of your vegetables, in your garden, and more creating a community interaction. There’s actually a type of farming called permaculture, which stands for permanent agriculture, and we use some permaculture practices on our land, but I think, for gardening, it’s really a useful school of thought to think about when you’re gardening, because it’s a holistic way of incorporating all these interactions, plant-microbe interactions. And if you really want to get into it, and your city allows, get a backyard flock of chickens, because what that does is give you free manure to spread on your garden. Not only that but also you the best eggs in the world. So, I think thinking about diversity, thinking about perennials, which we don’t think about when we grow vegetables, but just doing a bit of research on the perennials.
Tracey:
And the perennials, again, have to be there because the microbes need to be fed all year long.
Sarah:
Right. Another way to mimic perennials is cover crops. A lot of farmers do this. If they plant annual crops, they’ll plant a crop in the fall, and it grows all winter and then is dead in the spring when they plant their annual crop, and it’s there to hold the soil, to feed the microbes, to capture nutrients, and you can do that in your garden, too. You can cover crop any bare soil, so try to not have bare soil. Deep bed mulching is a great way to reduce weeds instead of tilling up your soil. It holds water, it keeps your soil at a really nice temperature.
Tracey:
Where is the best soil in the world?
Sarah:
I might be biased because I lived there for ten years but Iowa has some of the best soil in the world. That’s because of a history of tall grass prairie ecosystems in Iowa. This is throughout the prairies really. Tall grass prairie has built soil for hundreds of years because of the deep roots of the perennial plants and because of grazing of the bison and other animals on the prairie. So it has left this amazing legacy of very healthy soil rich in fungi and bacteria that have created a really beautiful habitat. That’s why some of the best crop yields we have right now are from those areas because those farmers are able to take advantage of that legacy of prairie soil.
Tracey:
Are we protecting those microbes there?
Sarah:
This concept of endangered microbes – what are we missing, what are we losing? We don’t really know except these sequencing technologies, one study that was from prairies it looked at remnant prairies, little patches of prairies that still exist that haven’t been tilled and farmed and compared the diversity and the microbes in those patches to close nearby farmland. And what they found was this dominance of a rare obscure type of bacteria called veroca microbia and they hypothesized that these veroca microbia are very important, played a very important role in building that prairie soil. And that with the transfer of this soil into agriculture that the veruka microbia are much rarer. Their abundance has really gone down.
Tracey:
So a bit of an endangered species?
Sarah:
It might be or at least hints at the concept of endangered species in microbes. The interesting thing about microbes is they are ubiquitous, they are everywhere. And so I think this is unknown but there is this hope that if we start building – if you build it they will come – that concept. If we start providing microbes with the buffet in the diversity that they need maybe these populations can bounce back if indeed they are really important for building healthy soil. Fungi especially are very sensitive to disturbance like tillage or chemical application and they are very reliant on interactions with plants. I don’t know if we know because of their sensitivity it’s less clear whether they can bounce back and how quickly they can recover when plant interactions are put back in place.
Tracey:
Can we talk a little bit about what does it mean to be organic? Does that consider the soil microbes?
Sarah:
I’m not a big fan of labels, and I think it’s really hard to be a consumer nowadays, because not all organic is good. A lot of organic is still a monoculture, or simple rotations. It still uses an excess of fertilizer. Yes, it’s organic fertilizer, manure, but it’s still excessive. It causes leaching of nitrates and other molecules into the environment. And so, I think if you were to be at a farmers market, or thinking about the food that you’re buying, looking for farmers that are diversifying their farms, that are adding diversity to their farms is, I guess, a really good way to start.
Tracey:
As a consumer, let’s say I shop and do my groceries at Walmart and Walmart is now carrying a lot of organics. Is that a good thing? Or is there another leap we need to take?
Sarah:
There is definitely another leap we need to take. And that is adding diversity into our rotations. So not having a farm that is just farming organic lettuce. Having a farm that is incorporating that lettuce with other crops to feed the microbes. Getting back to that study from Iowa State on long term rotations it was actually conventional farm that they were studying and what they found was by just simply extending the rotations, the amount of synthetic fertilizer, the amount of chemicals herbicides and pesticides that they were applying went down. And so you can have a conventional system that is adding industrial products but that has less of an impact on the environment. And in the same you can have an organic system that has a fairly large impact on the environment. So I guess I would ask your farmer at the local farmer’s market How do they care for their soil? Are they using a diversity of crops? Do they use integrated livestock? Do they use cover crops? A lot of farmers are trying to experiment with cover crops. That’s another big focus of the Farmer-Led Research program. Is how to incorporate cover crops as ground cover in the winter or anytime the soil would be bare to keep those microbes fed.
Tracey:
Thank you…
Sarah:
Yeah, my pleasure.
Tracey:
…for providing us with all this amazing information.
Sarah:
Thank you for having me, it was a pleasure.