(a) On an outline map of Nigeria, show the main soil zones (b) Name any one crop that is grown in each of the zones shown on your map (c) Describe the soil ...

As shown on the outline map above, Nigeria may be divided into three broad soil and crop zones:

Soil characteristics favouring the crops

• Zone A, groundnut: The soils are generally loose, light and sandy, making them easy to cultivate and allowing the developing groundnut pods to penetrate the soil. They are well aerated and well drained, so water does not remain around the roots. The broad, gently sloping plains also favour extensive cultivation.
• Zone B, yam: The soils are mainly deep, fertile sandy loams. They are loose enough for yam tubers to enlarge easily, while still retaining adequate moisture. They are well drained and well aerated, reducing rotting of the tubers. Their acidity is low to moderate and they contain sufficient nutrients and organic matter for yam growth.
• Zone C, cocoa: The soils are deep, fertile forest soils with appreciable organic matter from decayed vegetation. They are usually clayey loams or loams that can retain moisture and nutrients. They are well drained, often on gently undulating land, which prevents waterlogging. The soils are also commonly slightly acidic, a condition suitable for cocoa.

Therefore, the sandy northern soils favour groundnut, the fertile well-drained sandy loams of the Middle Belt favour yam, and the deep, moist, organic-matter-rich forest soils of the south favour cocoa.