Agricultural Science 2015 Jamb Examination

Deforestation in West Africa is driven mainly by human activities that demand more land for farming and settlements. The expansion of cultivated land is one of the leading factors, as farmers clear forests to increase farmland. High population growth rate increases pressure on land and resources, accelerating forest loss. Urban growth also leads to the clearing of forests to build houses, roads, and infrastructure. Conservation of wildlife in game reserves, however, helps protect forests rather than destroy them, which is why it cannot be considered a cause of deforestation.

Agriculture in West Africa supports economic development by creating jobs, reducing poverty, generating foreign exchange through export crops such as cocoa, coffee and cotton, and providing raw materials for agro-based industries like textile, food processing, and breweries. However, it does not provide armaments for territorial defence, since weapons production is unrelated to agricultural activities.

Agricultural development focuses on modernizing farming practices to achieve better yields and efficiency. It results in increased food production to meet the needs of the growing population. It also encourages investment in processing facilities to add value to produce, thereby reducing post-harvest losses. In addition, it raises productivity by introducing mechanization, improved seeds, fertilizers, and better management practices. However, development does not necessarily increase the agricultural labour force, since mechanization and technology often reduce reliance on manual labour.

The commercial land tenure system in many parts of West Africa does not allow farmers to use their land as collateral for loans, as they often lack formal ownership documents recognized by financial institutions. Without land titles, banks see lending as too risky, making it difficult for farmers to access credit, even if they are productive farmers.

Governments support agriculture through subsidies on inputs such as fertilizers and machinery, by creating agricultural development programmes that provide technical support and extension services, and by establishing farm settlements to encourage organized production. However, training of farmers' children specifically is not a direct government role in agricultural development, as education programmes are broader and not targeted solely at farmers' families.

Corms, rhizomes and tubers are all modified underground stems that serve as storage organs for plants. They store food in the form of starch and help in vegetative propagation. Examples include cocoyam (corm), ginger (rhizome), and yam or potato (tuber). They are not roots because their structure shows nodes and buds, features that only stems possess. They are not modified leaves either, and aerial stems are above the ground.

The A-horizon, also known as the topsoil, is rich in organic matter, microorganisms, and nutrients. This layer supports the highest level of biological activity because it contains decomposed plant and animal materials, fungi, bacteria, earthworms, and other soil organisms. These organisms play vital roles in nutrient cycling, soil fertility, and decomposition. The deeper layers such as the B-horizon and C-horizon are less biologically active since they contain fewer organic materials.