Question

What are clay soils and what do they look like?

Answer 1

Visually, clay soils seem solid with no clear particles, and may have a distinct red or brown colour when compared to surrounding soils.

Explanation:

Clay has the smallest particle size of any soil type (0.002mm diameter). This allows a large quantity of clay particles to exist in a relatively small space, without leaving much gap. This makes the soil very dense, thick and heavy. This density also makes the soil resistant to erosion. It is also difficult for plant roots to penetrate this type of soil.

Clay soils contain very little organic material. The slow permeability of clay soils results in them having large water holding capacity. As the soil particles are closely packed, it takes water much longer to move through. Once they absorb water and expand, they further slow down the flow of water.

Clay particles carry a negative charge. Nutrients like potassium and ammonium (that are dissolved in water) carry positive charge. These are attracted to the clay particles and this prevents them from being lost through leaching as water moves through the soil.