How to look after soils in our garden and city

View your soil as a living dynamic system that you are working in harmony with, understand its needs. If we look after it – it will look after us, the surrounding plants and other life.

Civilisations have often risen and fallen based on the fertility of their soil – when people’s lands degraded that they could no longer grow food they would migrate into surrounding areas and settle – nowadays with the global population growth there are very few unsettled arable lands available, making soil an important and limited natural resource.   

Soil plays an important function in many of earth’s larger systems, the nutrient cycle, the carbon cycle, and precipitation. These systems in balance provide a healthy planet. If soil is not healthy it cannot play its role in these bigger systems of the earth.

When soil is covered it is prevented from playing its important function. In the City of Melbourne around 60 per cent of the soil is covered with an impervious surface.

It takes a long time for soil to form. According to Dr David Pimentel, it takes 500 years to replace 25mm of topsoil lost to erosion.

Basically, soil is stressed globally and if we build healthy soils in our backyards, parks and gardens, we assist soil to continue to play its important role in providing us with food and functioning in the bigger cycles of the planet.

To know how to look after soils we must have a basic understanding on what they are, how they function and what supports/degrades them.

Soil is composed of mineral particles, organic matter, water, air and living organisms.  Soils rarely extend further than one to two metres below the surface with the area of the living soil biology sitting within the top six to 12cm.

Dr Elaine Ingham’s’ work in soil biology recognises that soil is the network of interacting living organisms within the earth’s surface layer. This community of living organisms controls and manipulates the chemistry of the soil, not the other way around. These living organisms also ultimately control water infiltration, mineral density, and nutrient cycling.

Sunlight and photosynthesis are merely the energy source – the fuel injection system. The engine that drives land-based life is the living soil. 

Soil problems generally fall into four categories each with their resulting conditions –

erosion, depletion, pollution (contamination and accretion) and compaction.

Our ethical task is to …

• Respect and leave untouched all naturally occurring soils that support unique eco-systems;
• Repair and protect all damaged soil; and
• Respect soils as living organisms
• An analysis of your current soil health is a first step. You can do a simple pH home test, and in-the-field tests, where you look at soil organisms present, the colour of your soil, drainage and even a taste test all of these can provide indicators of the quality of your soil. For more information go to thehomestud.com/diy-soil-tests/
• In permaculture some of the practices we use to prevent, soil problems, restore and maintain soil health are:
• Use land within its capability (i.e., soil type position and slope) anything with a slope of greater than 30 per cent we do not use for production.
• Don’t remove trees.
• Use gabions, terracing on steep slopes and revegetate.
• Manage water flow over the land so it does not cause damage, erosion (divert it, capture it, sink it).
• Reduce or no tillage, i.e., do not turn the soil which exposes soil life to the sun and elements destroying them.
• Don’t walk on wet soils.
• I recommend staying away from soil additives as we are not chemists and the amounts used can be too much, causing overload and overflow polluting surrounding gardens.
• Look after your soil life by protecting it and feeding it with green manures, plant legumes, cover crops, organic mulches, animal manures, nutrient broths, inoculants.
• Apply compost, chop, and drop to provide new nutrients for the soil and new structure.
• Use pioneers (plants) with deep taproots to stabilise soils and provide deep root penetration.
• In windy areas use windbreaks (can be a shrub) to protect your soils.
• Plant a diversity of plants with different root systems. Foliage etc, so different nutrients, layers of soil are occupied and mined from.
• Don’t use chemicals, pesticides, and fertilisers – these kill soil life and pollute.

Build your own soil by composting, growing green manures and chopping and dropping green matter into smaller pieces and leaving on the top of your garden beds.

Beware of buying in soil and compost. A recent article in the Diggers Magazine Winter Garden 2021 stated that many gardeners found the presence of selective broadleaf herbicides in garden soil that was deforming and killing their home-grown crops. This garden soil had been sold through garden centres and was made from commercial compost made from green waste •