Like the air we breathe, it is unexpendable. It is the life beneath our feet. It is a habitat for our decomposing friends and a home to the flowers we love. It balances temperatures and stores water. It is soil. And believe it or not, it is a huge contributing factor to climate change. Let’s start with a short video by Food and Agriculture Organization of the United Nations.
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Permaculture Soil Section:
Soil (or the skin of the earth) is made up of 3 mineral components: sand, silt & clay.
Did you miss the other weeks?
1-Ethics, 2-Patterns, 3-Microclimates, 4-Trees, 5a-Humid Cool-Cold 5b-Drylands, 6-Earthworks
Sandy Soil
Sandy soil is gritty to the touch and is not exactly ideal for planting. This is because it does not retain water easily since the particles are larger, do not compact easy, and therefore drainage is easier. This soil warms up a lot faster than those listed below, which can be beneficial.
Plant examples that can grow in sandy soil:
Lavender, Giant Allium, Siberian Pea Shrub, Black Locust
Silty Soil 
Silty soil is smoother feeling since the particles are smaller than those of sandy soil. It is more easily compacted and therefore tends to retain water longer, while also still allowing for some drainage.
Plant examples that can grow in silty soil:
Weeping Willow, River Birch, Yellow Iris, Sage, Japanese Maples
Clay Soil
Clay soil retains water better than both sandy and silty soil due to the fact that the particles are smaller than both. This allows little space for drainage as well as for air to pass. It is sticky to the touch (when wet), and can also be easily compacted.
Plant examples that can grow in clay soil:
Hawthorn, Juniper, Barberry, Hydrangea, Rudbeckia, Geranium
Loamy Soil
An ideal soil type. The loamy soil has a close balance between sand, silt, and clay. It allows drainage but at a speed that presents the nutrients long enough for the plants to absorb them. It is dark in color, fluffy and smells like that lovely “forest floor” smell.
Plant examples that can grow in loamy soil:
Summer Vegetables (eggplants, tomatoes, etc.), Semi-Hardy Crops (carrots), & the list goes on and on. Basically, any plant that states it likes “moist, well-drained” environments will be happy.
Permaculture Soil Section
- Soil is a medium for plants to grow in.
- It is a form of water storage, water supply, and water cleansing.
- It customizes Earth’s atmosphere
- And of course, it is a habitat for many organisms.
Layers of Soil
As with most topics, there are various versions of systems. The layers of the soils can be described in different ways. Some use the horizons of the soil which include 6 different horizons (or layers); O Horizon (humus), A Horizon (topsoil), E Horizon (eluviation/leaching layer), B Horizon (subsoil), C Horizon (regolith), R Horizon (bedrock).
In my Permaculture Soil Section we focused on a simpler version which only includes 3 layers:
Top Soil, Sub Soil, and Bedrock.
So let’s review!
Topsoil
- Topsoil is the most biologically active layer of the soil. It has the highest concentration of organic matter and is where most of the microorganisms are found. This dark soil is a result of Humus.
What is humus? “the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.” Humus is what gives soil it’s nice dark color. - Topsoil is where a majority of the root systems are found since it is the most nutrient-dense layer.
Subsoil
- The subsoil is the layer underneath the topsoil. Unlike topsoil, subsoil does not have a high-density of organic matter or humus.
- Some deeper roots are found in this layer like those of trees.
Bedrock
- This layer is found beneath the topsoil and the subsoil layers. It is the “unbroken” or “partially weathered” rock layer.
- This bedrock layer cannot be excavated by hand.
HEAR YE, HEAR YE.
HEDGEROWS MAKE A COMEBACK
READ ALL ABOUT IT
hedge·row
ˈhejˌrō
noun
plural noun: hedgerows
1. a hedge of wild shrubs and trees, typically bordering a road or field.
-Wikipedia
Hedgerows? Why hedgerows?
Let’s talk about their benefits…
The Benefits of Hedgerows
- Diversity! One of Permaculture’s favourite word! Hedgerows can bring a huge amount of diversity back into your fields. Be it with animal/insect diversity (through providing habitat), or with plant species diversity (through planting diverse plants), etc.
- Habitat! As I said, habitats for birds. Birds will reduce pest issues, and they will fertilize your soil and groundwater with nitrogen and potassium-rich nutrients.
- Mulch! Having on-site hedgerows will reduce the labour of bringing in large amounts of organic matter from far distances. This will provide a lot of organic matter to feed our microorganism friends in the soil and encourage a healthy biology in the soil.
Soil Biology.
The biology of the soil is (I believe) a very interesting topic. It explains how plants secrete exudates, that they create through photosynthesis, to attract fungi and bacteria. These fungi and bacteria are then eaten by the protozoa and the nematodes, which make the nutrients available to the plants. The soil food web continues with arthropods, then larger animals and so on. If you wish to learn more about Soil Biology and the Soil Food Web, I recommend checking out microbiologist Dr. Elaine Ingham.
Elaine Ingham Resources
Courses: Online courses in Soil Biology, Compost, Compost Tea and more.
Book: 10 Steps to Gardening with Nature
Talk: The Roots of Your Profit
This is a quick overview of some of the topics we discussed in
The Permaculture Soil Section
–
I hope you enjoyed,
& Don’t forget to leave a comment!
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Permaculture Soil Section