(a)(i) Name two distinct types of soil erosion (ii) Locate an area where each type is most common (b) Outline any three factors that have been responsible f...

(a)(i) Two distinct types of soil erosion

1. Sheet erosion (thin, even removal of topsoil by surface run-off over a wide area).
2. Gully erosion (deep channels and ravines cut by concentrated running water). Rill and wind erosion are also acceptable types.

(ii) Where each type is most common

• Sheet/wind erosion – the semi-arid far north of Nigeria (Sokoto, Katsina, the Sahel margin) with sparse cover and dry, loose soils.
• Gully erosion – the south-east, especially the Agulu-Nanka and Udi areas of the Anambra/Enugu region.

(b) Three factors responsible for gully erosion

1. Heavy, intense rainfall with strong surface run-off that scours and deepens channels.
2. Steep, sloping land that increases the speed and cutting power of running water.
3. Removal of protective vegetation (through farming, bush burning, over-grazing and building) on loose, easily-eroded sandy soils, so the bare surface is quickly cut into gullies.

(c) Three measures being taken to solve soil erosion in the area

1. Afforestation and re-vegetation: planting trees, grasses and cover crops to bind the soil and break the force of rain and run-off.
2. Construction of check dams, drains and terraces / contour ploughing to slow run-off, trap sediment and lead water away safely.
3. Filling and stabilising existing gullies with sandbags, stones and gabions, controlling farming on steep slopes, and public enlightenment against bush burning and overgrazing.