SoilSNC1D

Sand, Silt, and Clay

The mineral part of soil is pieces of broken-down rocks.

Largest pieces are sand, small pieces are clay, and the intermediate pieces are silt.

Sand, Silt, and Clay

These particles in different ratios make different types of loams.

More Than Just Rock

Only about 45% of soil is mineral.

The rest is:• Water (about 25%)• Air (about 25%)• Organic material (about

5%).

More Than Just Rock

Air pores provide oxygen for plant roots.Water dissolves nutrients in the soil, which the roots

can then absorb.

Organic Material

Of the organic material:• 10% is animals • 10% is plant roots• 80% is humus

Humus

Humus is the decayed remains of living creatures, broken down into a crumbly, dark dirt.

It holds water in the soil and provides nutrients to growing plants.

HumusUse of chemical fertilizers and pesticides can decrease

the humus and nutrients in the soil.

Chemical Pest Control

Natural Pest Control

The Layers of the Soil

Most humus is in the top layer of the soil (often called litter) and the topsoil beneath.

The Layers of the Soil

Most humus is in the top layer of the soil (often called litter) and the topsoil beneath.

Below the soil is the bedrock.

Topsoil

When land is developed, topsoil should be removed to be used somewhere else or it will be mixed up with the other soil components beneath the development and its productivity lost.

A topsoil screener for soil recycling

An Introduction to Soil Testing

pH

One test measures the pH (acidity) of the soil. Most plants prefer soil that is slightly acidic

(between 5.5-7).

pH

pH is a measure of the acidity of the soil. Most plants prefer soil that is slightly acidic

(between 5.5-7). However, some plants require very acidic soils

(less than 4.5) to survive (such as blueberries and azaleas).

pH and Hydrangeas

Interestingly, the colour of hydrangeas depends on the pH of the soil.

Nutrients

Healthy soil contains lots of essential nutrients: nitrogen, phosphorus, and potassium (potash).

Nutrient Testing

In the pH and nutrient tests, you will be adding water to the soil and testing the water (with powder in a capsule) and noting the colour change.

These tests require care and patience!