Everything you ever needed to know about soils [and what we're doing to them]

Soil is quite literally the foundation upon which our society is built, but is all too often overlooked when we think about protecting the environment, eating well or managing our resources sustainably.

However, healthy, productive soils are essential for our well-being, productivity and the environment.

So, what's so special about dirt – and where does it come from?

Soil is alive, made up of organic matter, minerals and organisms. Soil minerals are the by-product of rocky material that has been broken down by the forces of sun, wind, water, ice and organisms. It supports a living network of bacteria, bugs and fungus and provides a medium in which plants can grow. Although the earth is constantly producing soil, in reality it's not a renewable resource when we look at it in terms of human lifespans.

Australia in particular has soils that are old and slow forming taking hundreds, if not thousands of years to build. As we don't have much in the way of geological activity - such as earthquakes or volcanoes - to help rejuvenate our soils, they have become old and weathered over time. The rate of soil loss in Australia exceeds the production rate, which means that the condition of our land is slowly deteriorating.

What's happening to our soils?

Most of a soil's nutrients and living organisms are contained in a thin surface layer known as topsoil. Depending on environmental factors, this can range from thin and fragile to quite deep and more resilient. Topsoil and its associated nutrients is most commonly lost when we clear land - which we mostly do for agricultural use.

Once cleared, wind and water can easily strip away topsoils, leaving only bare, impoverished earth behind that demands a constant application of artificial fertilisers and irrigation to grow crops or feed cattle year on year. Soils may become compacted by heavy machinery or cattle, they can lose essential living organisms when they are constantly tilled or are exposed to chemical herbicides and pesticides, and they can be destroyed when rapidly evaporating water on irrigated land causes mineral salts to build up.

[Image: Nathalie Laurence]

What actions can you take to help out soils?

Luckily there's a few key things you can do to help, even if you don't have a garden.

First of all, lend your support to Aussie farmers that are using sustainable soil care practices! Have a chat with vendors at your local farmers' markets, or just check out what a company has to say about itself on their label.

Secondly, make sure any nutrients from organic waste that comes out of your household are getting returned to the soil and not ending up in landfill. It's estimated that around 50% of our annual household rubbish is made up of waste that can be composted.

Even if you don't have access to your own garden area where you can collect and convert your organic waste into new, nutrient rich soil, you'll find that many local councils around Australia have a green waste collection facility. So, if you aren't able to use it yourself, you can put plant prunings, grass clippings - and even food scraps in some areas – into your kerbside collection bins where it will be taken away to be processed at a central facility.

An added advantage is that the heat and methane generated by these large scale urban compost heaps can be used as a clean energy source as well!

Check out your local council services to see what's available. Of course if you have a garden, you can create a little closed-loop nutrient system in your own back yard. If you're not sure how to tend a compost heap, there's a wealth of books, online resources or gardening TV shows that can help you out – or consider joining a local community gardening group.

[Image: Natural Resources Conservation Service]

In the words of former US president Franklin Roosevelt,

It is no exaggeration to say that soils are one of the foundational pillars of our biosphere.

We rely on soil to grow our food, filter our water, provide nutrients and support habitat. The health and persistence of civilisations is inextricably linked with the health and viability of soils.

The 2015 Year of Soils is helping to promote the message about the importance of soil health, how soils are being damaged or lost, and what we can do to both protect and restore our remaining soils.

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[Header Image: Nathalie Laurence]