Thursday, 25 October 2012


What is soil?

Soil is found on the upper most layer of the Earth. It is a mixture of living things and non-living things.

Soil consists of a mixture of weathered rock, finely ground into powder, minerals, and a variety of living and dead life forms. This nutrient rich layer typically only extends downward a few feet, about as deep as plant roots extend.

Soil contains all the nutrients needed by plants to survive. Some areas, such as deserts, have very poor soils, in these locations it is difficult for complex plant life to take hold. Believe it or not, tropical rain forests also have poor soils. This is because most of the nutrients are already within living plants.

There are different types of soil. For examples, sandy soil, clay soil and garden soil.

 Sandy soil is usually yellowish in colour. It has very little bits of dead plants and animals.

Clay soil is red, brown or grey. It is a soil which has a heavy concentration of clay particles. 

Garden soil is black or brown in colour. It has lots of bits of dead plants and animals.

The Soil Layers

Soil is made up of different sizes of particles and different layers. Farmers need to know what kinds of particles are in their soil and how thick the layers are in their fields in order to decide how much and how deep to plow or irrigate.

Below is an example of the layers formed when we mix the soil with water.

There are bits of dead plants and animals floating in the water.
Clay, silt and sand are in the middle layers.
Small stones are found at the bottom layer because they are the heaviest objects.