Lesson 3: WORMS
Class Room Work

1. Worm species

We started the class with some basic information about worms. The following points proved to be a good starting point for this topic.

There are more than 3,000 species of worms. They are very ancient some species have been around for several hundred million years. They are found in a number of different colours - brown, purple, red, pink, blue, green and light tan and range from 2.5 cm to an Australian giant longer than 3 metres. Charles Darwin studied and wrote about worms, he said:

"It may be doubted whether there are many other animals which have played so important a part in the history of the worlds as have these lowly organised creatures."

Ten thousand years ago, immediately after the last ice age, lumbricoid earthworms were only found in restricted areas, such as the valleys of the three great civilisations - the Indus, the Euphrates and the Nile, where crops were grown in deep, fertile soils with hardly any cultivation.

2. Biology of worms

Figure 6 The main parts of a worm's body

A worm can be considered to be just a large stomach, surrounded by muscle. It pumps itself through the soil eating any small morsels that appear in front of it.

3. Worm castings

The gut of a worm is truly amazing it converts both organic material and rock particles to plant food with a pH of 7.0 (this will be discussed further in lesson 5). This means that worms and their excrement are really important in our soils.

4. Worms as compost makers

Most worms work in the soil but some like a richer diet. These kinds of worms are known as manure worms. Manure worms can be used to digest kitchen scraps and ruminant manure, to make a wonderful fertiliser for gardens and potting soil.