What is Soil?
Soil Is A Fascinating Mix of Weathered Rock, Living Organisms & Much More. Soil Is What Supports Life On Earth. Without It, Most Plants Can’t Live And Without Plants We Would Die. Soil Is Often Called Earth & It’s So Important We Call Our Planet, Earth. It’s That Essential To Life.
Later in this series, I’m going to explain how soil is made up of weathered rock of various sizes, with physical and chemical qualities that help our plants grow. But it’s more than weathered rock. That would imply that soil is an inert dead medium, whilst it’s actually an ecosystem of organisms living within a complex mix of minerals and organic matter that often includes large volumes of gas and water within the spaces between the soil particles.
That might sound complicated. But it really isn’t once it’s explained in simple terms. And that is what I plan to do in this series of pages about soil.
Is Soil Alive?
No .. and yes.
Soil isn’t alive in the way you and I are. It can’t breathe, eat, drink, reproduce or even catch a bus to go to the pub. But amongst all the inert weathered rock particles there are spaces where living organisms do live. The very small ones such as bacteria, viruses, fungi etc are called the microfauna. And the big ones, such as worms, beetles, slugs, rabbits, foxes, otters and badgers, are called the macrofauna.
Without the microfauna and macrofauna soil is “dead”. There’s just the rock derived particles, minerals and organic matter. Chemical reactions will take place and there will be some physical movement as water percolates through the soil. And we’ll see erosion and physical action taking place if there is enough water to move the particles. But it isn’t “alive” in this state.
For plants to live, survive and thrive for long periods in the soil it needs to be complete. The soil needs a microfauna at the very least.
That not to say we can’t grow plants in artificial conditions such as hydroponics, grow bags etc. But where we do we are imposing artificial conditions and need to manage a lot of things if we are to get good results.
What is Soil?
To recap. Soil is made up of rock particles, (these are often made up of a number of minerals), organic matter, gas, water, and living organisms of various sizes. The rock particle elements are derived from the weathering of rock by heat, cold, water and wind erosion, acids and fungi ( fungi surprise a lot of people and I’ll explain more about that in a later article).
Are All Soils The Same?
Soils vary in many ways. In fact, they vary so much that a forensic scientist can take a soil sample and determine exactly where it came from. There are many examples of how forensic scientists have solved crimes, including murders, by being able to identify exactly where soil on a suspects shoe or car tyre came from.
As a student, I studied pedology. That’s the study of the physical and chemical properties of soil, how organisms are involved in soil production plus the classification and mapping of soil, their origin and formation. In those days a pedologist would mainly work in agriculture or related business. Today, they are just as likely to work in forensic science where they can analyse the physical properties of soil and, in some cases, identify its origin within a few metres.
Alongside the pedologist, the forensic science unit may well have microbiologists investigating the bacteria and fungi, mineralogists checking out the chemical constituents of the soil and palynologists checking out the pollen grains in the soil. And let’s not forget the botanists who can often identify the rough location of a soil sample by the seeds in it. Together they are able to pinpoint soils very precisely because each location has unique soil.
On a more mundane level soil is classified into various physical types. Soil classification and why it’s important is a topic I’m covering in another post and I’m going to show you how you can simply test your soil at home and get a good idea of your soil classification.
Does Soil Need Digging?
Gardeners seem to delight in hard work and love digging and rotovating the soil. But is it really necessary? I dig into the answer in part of my page on Gardening Myths
The article on No-Dig is also worth a read.
More On Garden Soils