(a) Solution Definition
(1) Soil profile is the vertical section of the soil from the surface down to the bed rock or parent rock below
(2) Soil profile is a vertical section through the soil showing various horizons of the soil
(b) Labelled diagram
(1) Title
(2) Zones
(3) Labelling
(c)(i) A- Horizon
(1) It is the top soil
(2) Contains remains of plants and animals undergoing decomposition to form humus
(3) It is also known as the eluviation zone
(4) A zone of maximum biological activities of plants and soil micro-organism
(5) Darker in colour than other zones
(6) Most plant roots are anchored there.
(ii) B — Horizon
(1) It is called the subsoil
(2) It is a zone of accumulation of soil nutrients due to leaching from A -horizon
(3) It is also called zone of illuviation
(4) Humus and other organic matters washed down from A — horizon are converted to inorganic compound
(5) Rich in iron, aluminium and magnesium
(iii) C — Horizon
(1) It is called the parent material horizon
(2) Contains unweathered rocks
(3) Contains materials from which A and B horizon are formed
(4) Underlain by hard unweathered rocks