(a) Explain briefly four factors of soil formation. (b) List four chemical processes in the weathering of rocks.

Answer Details

(a) Four factors of soil formation

1. Parent material: the type of rock from which the soil is formed determines the mineral composition, texture and colour of the resulting soil.
2. Climate: rainfall and temperature control the rate of weathering; heavy rain and high temperature speed up rock breakdown and leaching.
3. Living organisms (biota): plants, animals and micro-organisms add organic matter, aid weathering and mix the soil, forming humus.
4. Topography (relief): the slope of the land affects drainage, erosion and the depth of soil that forms; and time, since soil development takes many years.

(b) Four chemical processes in the weathering of rocks

1. Oxidation
2. Hydrolysis
3. Hydration
4. Carbonation (and solution)