3. (i) This is a diagram of a typical soil profile. Describe each horizon (A–C). The O horizon has been described for you in detail. You should use the words provided here to help. Horizon
Topsoil Lighter in colour Bedrock
Most fertile Solid rock
Dark in colour Parent material
horizon A
B horizon
O horizon: The very top layer of the soil. The soil we see. It can be covered in plant litter such as leaves and twigs. A good horizon for plants and other organisms to live in.
C horizon
Exam Hint
Clearly define the difference between each horizon. What colour is it? What is it made of? How does it affect fertility? Use bullet points or sentences to answer.
(ii) (a) Leaching affects soil fertility. Give a brief description of what leaching is.
(b) Examine the cartoon image. On the following page, explain two reasons why severe leaching is bad for soil.
Exam Hint
Interpreting information from a cartoon is a popular exam question. Describe what you see in an image.