What is the Soil Food Web and Why it Matters
In this episode, we’re going to explore the soil food web—from worms to nematodes, to bacteria, fungi and so much more. The soil food web is the foundation that supports a thriving and abundant environment. If you want to cultivate abundance for people, plants, and wildlife then you need a healthy soil food web. Let’s dive in.
How often have you been told that what matters for your soil is nitrogen, phosphate, and potassium? Or NPK.
These 3 are the so-called “big 3” primary nutrients found in commercial fertilizers.
And most soil tests focus on these 3 along with other important micro-nutrients. Things like calcium, magnesium, iron, and many others depending on the soil test. Often soil amendments focus on these micro-nutrients.
But these soil tests are all missing out on the single most important element of healthy soil.
And that is the life that makes up the soil.
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Soil wouldn’t be soil without the life in it. When you remove the life from the soil it becomes dirt.
But far too often we ignore the life in the soil and focus on those big 3 nutrients by adding fertilizer to the soil and then add amendments for various micro-nutrients.
If you instead focus on supporting a diverse soil food web you can stop worrying about adding these nutrients to your soil.
Your soil already has what your plants need to thrive in it. But it may be locked up and not accessible to your plants.
Soil life through the soil food web can unlock those nutrients making them accessible to your plants.
But beyond making nutrients available to your plants the soil food web can also protect your plants from diseases and pests and also improve the structure of your soil.
If you want to cultivate abundance for people, plants, and wildlife then supporting the soil food web is key.
So let’s dive into the soil food web and look at what it is, why it’s important and 3 steps you can take to support it. And also make sure to grab your free guide to building healthy soil.
Before we look more closely at the soil food web I do want to take a moment to read a recent review from Tom Knezick on Apple Podcasts.
Tons of edible information in bite size episodes. I didn’t realize how many native plants were out there to eat! Keep it up Daron!
Thanks, Tom for the review—there really are just tons of native edibles. I feel like every year I add a few more to my list. Tom along with Fran are hosts of the Native Plants, Healthy Planet podcast presented by Pinelands Nursery. I was recently a guest on their show and I highly recommend checking out their podcast. They interview some of the top minds in ecology, restoration, conservation, and of course, native plants. So check them out and tell them Growing with Nature sent you.
And if you like what you hear today, then please leave a review on Apple Podcasts or wherever else you listen. Your review will help more people find us.
People like you, who want to bring these skills home, to enjoy wildlife, grow more food, and help heal our living world.
Okay, let’s get started.
Further Reading: Growing with Nature episodes and blog posts with more information about the topics covered in this episode.
- 3 Ways Perennial Plants Help Build Soil
- 3 Benefits of Fungi on Your Property
- What Happens When Plants Break Down? (And Why it Matters)
Books and Other Resources
- Mycelium Running: How Mushrooms Can Help Save the World – by Paul Stamets
- Teaming with Microbes: The Organic Gardener's Guide to the Soil Food Web, Revised Edition
- Dr. Elaine’s – Soil Food Web – How it Works
- The Secret Life of Soil – Oregon State University
- How Trees Secretly Talk to Each Other – YouTube
- This Underground Economy Exists in a Secret Fungi Kingdom – YouTube
- USDA Soil Biology Primer
- Plant Root Exudates
- Some Tips on Making Compost
- Compost Teas and Extracts: Brewin’ and Bubblin’ Basics
What is the Soil Food Web?
Have you ever taken a handful of soil from a healthy forest floor and just smelled it? If you haven’t you really should.
The smell will be earthy, moist, and just good.
It’s the smell of life.
And that is the same smell that you should find in healthy soil with a thriving soil food web.
If you take a hand full of sand or dry dirt it will smell different—subtle but your nose will be able to tell the difference.
You want the soil on your property to smell like a forest.
That earthy smell comes from the fungi, bacteria, worms, bugs, nematodes and so much that makes up the life of the soil food web.
Some of these are shredders and decomposers—they break down and eat any dead organic material like leaves, stems, branches, and dead roots in and on the soil.
Think about things like pillbugs, earthworms, and millipedes. These are some of the larger types of life found in and on the soil. They break up or shred things like leaves into smaller pieces that other life can better use.
Bacteria and fungi are examples of decomposers. They help break down organic materials like leaves, branches, and stems. This makes it easier for shredders and other soil life to do their job of breaking up the larger materials.
Think about how much easier it is to break a rotten branch compared to a fresh branch.
Then there are the predators in the soil food web. Things like predatory nematodes, protozoa, larger arthropods like centipedes, and even slime mold.
These predators eat the shredders, decomposers, and other life found in the soil. This releases nutrients from say a rotten log into the surrounding soil that then feeds your plants.
Plus those predators can help keep so-called soil pests like root-eating nematodes and disease-causing fungi in check.
Just like predators like ladybugs can keep aphids in check. The same principle applies in the soil—just at a smaller and often slower stage.
And there is so much more than these examples of soil life. Healthy soil is just filled with life—there is more life in one teaspoon of nice healthy soil than people are living on Earth.
All this life is the foundation of a healthy living world that is filled with abundance for people, plants, and wildlife.
Why the Soil Food Web Matters
So why is the soil food web the foundation of a healthy living world?
Let’s start with a different question—does anyone add fertilizer or amendments to a healthy forest?
No—so how do these areas thrive?
The soil food web is a big part of why these natural areas are filled with abundance. As branches, leaves, stems, and even animals die and fall to the ground the life in the soil starts to break it down.
Some soil life such as bacteria eat the dead material while others like protozoa eat the bacteria. There is a complex mix of prey and predators in the soil food web.
This cycle releases nitrogen and other nutrients that your plants need.
For example, bacteria-eating protozoa can provide plants with 80 percent of their nitrogen needs. And that is just one example.
All the nutrients your plants need can be provided by the soil food web.
And fungi will even interact with your plants in a complex system sometimes called the wood wide web. This is a complex network of fungi and plant roots that share nutrients and water between them.
The result is your plant roots are essentially greatly extended giving them access to nutrients they couldn’t otherwise reach.
And your plants will feed this soil life by releasing what are known as root exudates into the soil. These are essentially little packets of carbohydrates and other compounds that fungi and other soil life can eat.
A large portion of the carbohydrates your plants make through photosynthesis isn’t used for growing—instead, they’re released as root exudates into the soil.
The reason your plants do this is to get access to nutrients like nitrogen that they need through the soil life.
This complex interaction creates a diverse soil food web that in turn creates abundance above ground too filled with plants and the wildlife they support.
And beyond providing nutrients for your plants the soil food web has 2 other core benefits.
A diverse soil food web will naturally keep disease-causing fungi, bacteria, and other so-called pests in check.
People often want to get rid of nematodes since they think they will eat plant roots. And some do—but many nematodes are predators that eat the root-eating nematodes.
So just like you want to promote songbirds to eat caterpillars you can also promote the predators in the soil that will keep the disease-causing fungi, bacteria, root-eating nematodes, and other potential problems in check.
And a diverse soil food web will also improve the structure of your soil. Earthworms create tunnels that plant roots can easily move through. And fungi will hold the soil together to keep it from eroding.
But these are just a couple of examples.
The reason the soil of a healthy forest has that nice moist chocolate cake type structure is that it’s filled with life.
So if you want healthy soil that provides the nutrients your plants need to thrive, keeps diseases in check, and has good structure then you’ve got to support the soil food web.
3 Steps to Support the Soil Food Web
Now that we’ve explored what the soil food web is and why it’s important I’m sure you’re wondering how you can support it on your property.
Luckily, it’s quite easy to do.
There are 3 core steps to support the soil food web.
- Minimize disruption—top tilling your soil.
- Cover the soil with mulch—living mulch works too.
- Feed soil life by keeping living roots in the ground all year.
You’ve got to stop tilling if you want to support a diverse soil food web. It’s okay to till an area once to get it prepared for future planting. But once it’s prepared don’t till it again.
Every time you till the soil you kill the life in the soil. And you also destroy the structure of the soil. The result is a depleted soil food web that won’t be able to provide the same benefits as a healthy diverse soil food web.
The next step is to keep the soil covered with mulch. This can be woodchips, chop-and-drop plant materials like spent veggies and flowers, fall leaves, and living plants.
All this will help feed the life in the soil and it will keep the soil cool and moist making it easier for the soil life to thrive and do what they do best—create rich healthy soil.
And finally, make sure to keep living roots in the ground all year-round. In annual gardens, people often leave the soil bare over the winter.
But without living roots in the ground to release root exudates and feed the soil life your soil food web will be less diverse and less abundant.
The key is to add perennial plants and perennial foods to your growing areas. Even in the winter, these plants will still support soil life.
You don’t have to shift entirely to perennial foods but the more you can the healthier your soil will be. And in turn, the better your plants will do.
If you plant perennial plants, stop tilling and keep the soil covered with mulch or living plants you will have a thriving soil food web under your feet.
It won’t take long for the soil life to move in but you can speed up this process by adding compost or worm castings to your soil. This will give a nice boost to your soil food web by adding life to it.
Compost extract and compost tea is another great option to do this.
And once you’ve got a thriving soil food web your plants will just take off. Building healthy soil by supporting a diverse soil food web is one of the best things you can do to heal the living world around you.
And stay tuned for our next episode where we will explore a food forest. Food forests are a great perennial-based system for growing food in a way that supports a diverse soil food web. Plus, they support wildlife and are just beautiful all while providing food for your family and your community.
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