Lesson 4: Types of Soil

Soil can be divided into three main types: clayey soil, sandy soil, and silty soil. 

Sandy Soil

Sandy soil has a loose texture, is unable to hold much water, and drains very easily. This easy drainage leads to a rapid loss of plant nutrients and water, so sandy soil is generally not very fertile. Sandy soil warms up quickly when the weather is hot and its organic matter content is low. Because its particles are light and there is little to hold the soil together, sandy soil is easily eroded by wind and water. Farmers who work in sandy soil know that water drains away quickly from this kind of soil. When they irrigate, they use small amounts of water to minimise the loss of plant nutrients and the loss of water to deep levels of the soil where plants cannot reach it.

Clayey Soil

Clayey soil drains slowly, and it can easily be compacted. The size of the particles in clay soil is under 0.002 mm, which means the soil is very dense. Plants can struggle to grow in dense soil. Because clayey soil drains slowly (as little as 1 mm an hour), it can hold a lot of water and retains plant nutrients well, meaning it is generally fertile. This kind of soil tends to have a high level of organic matter and it warms up slowly in warm weather. Clayey soil resists wind and water erosion better than other soils because it becomes hard when dry and sticky when wet.

Siltey Soil

Siltey soil is the third primary type of soil. Silt has particles of between 0.002 mm and 0.05 mm, making it less prone to erosion than sandy soil. Soils with a high silt content are often more fertile than other soils because they are able to retain a high quantity of plant nutrients. Siltey soil becomes slippery when wet.