The Self Sustaining Garden: Our Place in the Soil Food Web

by Paige Lahnam

fungiroots

We become a dozen different people when we step into our gardens: architects, chemists, chefs, doctors, exterminators, and various others.  When the earth needs to breath, we are there to turn it, when it is hungry, we feed it, when it crumbles and washes away beneath our feet, we build more, making the gardeners’ job a relentless one.  It is hard to imagine how the soil gets along without us in our surrounding forests.  Who is there to treat common issues of those plants?  What sort of prevention strategy is in place?   

The reason our backs ache and our hands grow calluses like weeds is that in nature, the work that we take on—bold and ambitious gardeners that we are—is divided amongst trillions of organisms in the soil food web.

Maybe we are a little overworked.

With a little more awareness and a lot less work, we can promote a healthy, neat garden with a wild spirit.

After years of tilling and fertilizing, modern farms struggle with erosion and depletion of soil nutrients.  We compulsively remove our grass clippings, leaves, and yard waste, taking nutrients away and letting the earth give and give until there is nothing left.  By building our own soils we alleviate this problem and lock nutrients into our gardens, keeping nitrogen, phosphorus, and potassium right where they belong: nourishing our plants and cycling from one character in our soil story to the next.

There is a community weaving itself beneath our feet: a vast interconnected network of life.   We forget about that cylinder of root mass once it is removed from its plastic sheath and submerged in the hole.  The seeds that slip from paper sleeves also slip our minds until they emerge from the ground as plants.  Where do those roots go and who do they meet along the way?

The soil food web contains many characters, most of which we have all encountered in our own soil explorations.  Earthworms, ants, centipedes, and ladybugs are old friends, and contribute to a much larger system that is seldom seen.

When leaves fall from trees, they drop to the soil where shredders like ants and millipedes break the leaves apart so that they are easier for the bacteria and fungus to digest.  Nutrients such as nitrogen and carbon are absorbed from dead material and encased inside the bodies of fungus and bacteria.  At this point, plants cannot absorb these recycled nutrients.  They are working on a scheme of their own and produce excess sugars, which sweat out of their roots, providing a tasty snack for any fungi or bacteria hanging around. Mycorrhizae intertwine themselves between roots, and bacteria cling to particles of soil nearby.  When a nematode comes along and takes a delicious bite from a mycorrhizal hyphae, the nutrients contained within the body of the fungus run right through the nematode and are deposited near the roots, ready to be sucked up and put to good use.  This is also true for hungry protozoa that eat bacteria.

It is much easier to establish a living system that feeds itself, retains water, and aerates the soil than to be the personal servant of each needy plant in your yard.

Common practices such as tilling and adding inorganic fertilizers to the ground kill the beneficial organisms that supply our plants with nutrients.  This lack of nutrients necessitates a constant influx of fertilizer into the soil, most of which is flushed out by water before it even reaches the roots.  The salts from the fertilizers dehydrate the sensitive bodies of microorganisms, sterilizing the soil, however, it is possible to inoculate sterile earth with life.

Establishing your Food Web:

The first step to obtaining better soil is observation.  Try to see what is living in your backyard.  There are ways, such as setting pitfall traps (burying a cup so that bugs fall into it and cannot climb up the sides) and soil sampling, to determine the makeup of your food web.

Because there are many things that we do that harm helpful organisms, getting to know the beasties that occupy your plants’ space will help you learn the good guys from the bad.     

Once you’ve identified your true friends, inoculation is the next step.  Compost is pre-soil, partially decomposed and full to the brim with beneficial organisms.  If it’s decomposing, it’s alive.  By heaping compost on top of your existing soil, without mixing it in, you are introducing this decomposition into your food web and soil is being built beneath that compost.  A layer of wood chips can be put on top of this to act as both a food source for the soil building organisms and as a buffer for weeds, drought, and cold weather.

When you make these initial changes to your garden, the only maintenance required will be raking up any weeds that do manage to sprout and adding wood chips.  You will no longer need to feed (or you can feed your organisms by adding organics like kelp meal) and only occasional watering while planting will be needed.  You will have created a sort of terrarium under your feet; a flourishing self-sustaining ecosystem resembling an old growth forest, or other wild area.

As far as disease is concerned, keeping your plants healthy allows them to fight infection.  An aerated compost tea can assist with any health issues as it contains a high concentration of our compost critters and can be sprayed on leaves as well as used as a soil drench.  Beneficial bacteria colonize this space, preventing disease causing bacteria or fungus, like powdery mildew, from taking up residence.

Our involvement in our gardens becomes less frantic when we start paying attention to what existed before us and what will subsist after us.

We can become a part of the food web in our gardens, abandoning our posts as lonely warriors and joining forces with a fun cast of critters who know when to work and when to kick back.  By setting up our plants for success, we get a front row seat to their inherit brilliance.

Resources 

Lowenfels, Jeff, and Wayne Lewis. Teaming with Microbes: The Organic Gardener’s Guide to the Soil Food Web. Portland, Or.: Timber, 2010.

Back to Eden. Dir. Dana Richardson and Sarah Zentz. Perf. Paul Gautschi. 2011.

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2 thoughts on “The Self Sustaining Garden: Our Place in the Soil Food Web

  1. Pingback: Learning About Compost - Homemade Food Junkie

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