(a) (i) On an outline map of Nigeria, show the area that is mostly affected by desert encroachment (ii) Locate an name two important towns within the area (...

Answer Details

(a)(i) Area of Nigeria mostly affected by desert encroachment

On an outline map of Nigeria the desert-encroachment (desertification) zone lies in the extreme north, along the border with Niger, covering the Sahel/Sudan savanna belt of the far northern states such as Sokoto, Katsina, Kano, Jigawa, Yobe and Borno. This is the semi-arid belt just south of the Sahara.

(ii) Two important towns within the area: Sokoto and Maiduguri (also acceptable: Katsina, Kano, Nguru, Damaturu).

(b) Major causes of desertification

• Low and unreliable rainfall with long dry seasons and recurrent drought in the Sahel, which reduces vegetation cover.
• Deforestation and removal of vegetation for firewood, timber and building, exposing the soil.
• Overgrazing by too many cattle, sheep and goats, which strips the grass cover and tramples the soil.
• Over-cultivation and poor farming methods that exhaust the soil and leave it bare and loose.
• Bush burning and wind erosion that carry away the fine topsoil, leaving infertile sand.

(c) Two possible ways of combating this hazard

1. Afforestation and shelter belts: planting rows of drought-resistant trees (for example neem) to form the Great Green Wall, which binds the soil, checks wind erosion and restores vegetation.
2. Controlled land use: regulating grazing and farming through rotational grazing, reduced herd sizes, controlled cultivation, and providing alternative fuel to reduce firewood cutting, so that the natural cover can recover.

Also acceptable: irrigation and water conservation, and public education on environmental protection.