Mother Nature's Soil Tilling Methods

I'm not here to argue the pros & cons of people tilling the soil. But I'd like to explore the ways that nature churns, flips, moves, or otherwise mixes up soil. I've discovered a number of ways of "natural tilling" by observing on my own farm. Some of the soil movement involves several feet in depth, others only an inch or so. But it's amazing how it effects the nature of the soil, though it may takes years, decades, centuries, or even eons. Mother Nature isn't in a hurry, like us humans.

I'll start the list with ants. I have several different species of ants on my farm. Some are ground dwellers, others live up in the greenery. I've noticed that some ants seem to create rather shallow ground nests. I've excavated a few that were only 6" deep or so. But I've come upon other species with really deep nests. We recently removed a damaged tree and found active ants almost four feet down under the tree. I don't know if their nests around here go deeper, because our ground is mostly lava rock. But it would be interesting to check that out.  

Ants bring deep soil to the surface. They take various organic materials down into their nest tunnels. Does that material eventually degrade into soil? What about the dead ants, egg cases, ant poop? I suspect that it does.

Ants can be both good and bad. While they may cause damage in a garden or orchard, they also improve the soil. They move soil particles around creating drainage. They "lighten up" the soil. Their tunnels allow air and moisture to enter the soil. They move nutrients around, burying them into the soil.

I find ants to be interesting natural tillers. I can't say that I like them all, especially the stinging ones and those that get into my house. But they are interesting to watch.

What a great topic Su Ba, I love this and I like ants, as long as they aren't where I don't want them to be. (when that happens I encourage them to move by spreading spent coffee grounds over their nesting area).
Your description of ants at work is superior and I agree with your suspicions. They are one of the best at what they do for the soil and I wish more people looked at them as soil improvers.
I recently read about an entomologist who is studying ants, he makes casts of ant colonies homes and has discovered that one colony can occupy 300 sq. feet of surface soil.
Their tunnels are vast and have rooms for brood, living quarters, food storage and waste disposal. It is really quite interesting to get glimpses into how much like bees ants really are.

On to my contribution to this thread.

Our mother uses lots of animals as well as insects, I don't like to use the term tilling when talking about most of these doing the job nature uses them for, I prefer to use the term disturbance.

Horses, cattle, goats, donkeys, sheep all do a form of disturbance called trampling where the surface of the soil gets pushed down so that other soil will end up covering and filling in the hoof divots.
This hoof action also pushes into the soil some of the animals manure so it gets below the surface instead of leaching those nutrients into the soil slowly.
Animals are one of the integral parts of a healthy ecosystem because of their ability to trample, trim and manure.
These benefits work best when they can stop feed, do the work for nature then move on to a new area, we mimic this by paddock pasturing and moving the animals along fairly quickly like if they were on open range.

Hogs on the other hand do indeed fit the term tilling since their rooting is very similar to the actions of a plow.
Hogs also create wallows which become muddy puddles full of manure and urine and hogs tend to stay in a smaller area when there are food sources nearby.

Nature also uses rain and wind to create pockets of heavy disruption which allows for deep mixing of the soil horizons, but that is for another post here.

Redhawk

I've got to list trees blowing over as one of the big "disrupters".  I have seen large trees tear up a chunk of earth several feet deep and 20 or 30 feet across.

When nature decides to use High Winds for disruption what we call pit and mound formations are created by the trees that are blown down.
This form of disruption mixes soil types through as many as three horizons, though two horizons are the norm.
The root system coming up out of the soil tosses the top soil towards the tree's top and it fractures and lifts the soil the roots were in, this settles into the pit and around it thus mixing these layers which allows a dispersion of the root system microbiome organisms as well as blending soil types.
New plants will grow in the pit and up the sidewalls, rocks will be exposed to weathering thus adding to the mineral content of the top soil and the root retained top soil will end up washed, by future rains, down into and around the pit.
As time goes by, the tree will become habitat for fungi which will decay the tree and the decayed cellulose and lignin will fall to the soil surface and become habitat for many insects, fungi and bacteria, worms, nematodes and all the other microorganisms found in healthy soil.
Eventually all this organic matter becomes part of the soil and the great circle of forest life continues along.

Addendum: *
If there has not been enough rain to saturate the ground these same wind events can snap trees off near their bases and you get an area now sun exposed for new seedlings to get a start along with the downed trees going through the decomposition process.
An area that has had this happen to it looks a lot like a bomb went off, the trees usually lay all in one direction which indicates which way the wind was blowing. Surveying such an area after just a few months will show signs of decomposition already beginning and new, seedling trees usually are already taking advantage of the new exposure to sun light. With in just a few years, nature will start the forest succession again, there will be small trees, shrubs and bushes growing and this will continue until the trees fill the sky, producing a shade canopy once again, the shrubs and bushes die off from the lack of sunlight and the forest is re-established.*

On Buzzard's roost we have at least 12 trees that have been blown down by our high winds, most are about half way through the decay process at this point and you can visually see how this process works to enrich the soil, provide habitats and nutrients that were used by these trees now returning to the soil.
The resultant pits are either occupied by burrowing animals now or they are full of new plants.

Redhawk

Voles, moles, and gophers !

In the mountains around here, flooding and mudslides may create widespread disruption of soil. Pretty much any thunderstorm in the desert moves a tremendous amount of soil downhill. These movements can be particularly noticeable after a wildfire. Annual runoff floods, and periodic flash floods both move plenty of soil to new places. The flash floods sometimes move dramatic amounts in a few hours.

I visited a valley one time where an earthquake moved a mountainside from one side of a valley to the other. That was astonishing.

There is a mountain near my farm in which falling rock crushes any vegetation below it, so a section of the mountain is constantly churned, and remains free of significant vegetation.

The particular species of ground dwelling birds and mammals are different here than mentioned previously. Around here, prairie dogs can create extensive swaths of disturbed soil.  

Miles Flansburg wrote:Voles, moles, and gophers !

Oh my!

I suppose on a scale from fast till to slow till:

1. Marsupials (mainly kangaroos, wallabies, bandicoots, wombats, bettongs)
2. Monotreme (Echidna)
3. Earthworms
4. Ground dwelling spiders, wasps and bees
5. Me (I'm a lazy part of Mother Nature!)

Factoid: one species of Bettong (the Woylie), whose diet mainly consists of underground fungi, is credited with spreading beneficial fungal spores in our desert ecosystems.

One metaphor that stuck in my mind from readings was (and I am probably not quoting this completely accurately) the concept that the burrows and tunnels and dens and holes are like the lungs of the earth, and when it rains, they fill up, and the earth exhales, and when the water dries up, the earth inhales.  I like that image. Mollison I believe, or was it Lawton?

These are all great answers!!!

I was reading the news today and an article mentioned dust storms in India. Ah-ha, I thought! Another example of nature mixing the ground up.

And thinking about ground tunneling, termite mounds also came to mind.

Trace Oswald wrote:I've got to list trees blowing over as one of the big "disrupters".  I have seen large trees tear up a chunk of earth several feet deep and 20 or 30 feet across.

Wow yes, the blown over tree. I have memories of when I was a young kid where some old giants got blown over on my great grand parent's land - the size of the exposed root mound and resulting hole was stunning.  Redhawk explained the process amazingly...I'm relatively new to learning the terms and techniques people are intentionally using like "hugulkulture" "swail" and the like - So cool how nature takes a tree and creates all these settings while adding it's own fertilizer and covering, too :)

Armadillos are excellent little soil disturbers.