(a) State four characteristics of a fertile soil. (4 marks) (b) Discuss briefly three factors that affect land availability for agricultural production in W...

(a) Four characteristics of a fertile soil [4 marks]

• It is rich in plant nutrients (nitrogen, phosphorus, potassium, etc.).
• It has good structure and texture that allow proper aeration and root penetration.
• It has a good water-holding capacity while still draining well.
• It has a favourable (near-neutral) pH and a good population of soil living organisms plus adequate organic matter (humus).

(b) Three factors that affect land availability for agricultural production in West Africa [6 marks]

• Land tenure system: Communal and fragmented ownership makes it difficult for a farmer to acquire and hold large continuous pieces of land for farming.
• Population pressure and urbanisation: Growing population and the expansion of towns, roads and industries take away farmland for building and other non-farm uses, reducing the land available for agriculture.
• Nature/topography and soil condition: Rocky, mountainous, waterlogged, eroded or desert (arid) land is unsuitable for cultivation, so such areas reduce the amount of usable farmland.

(c) Four benefits of draining farm lands [4 marks]

• It removes excess water and prevents waterlogging of the soil.
• It improves soil aeration, which favours root respiration and the activity of soil organisms.
• It raises soil temperature and allows the land to be worked and planted early.
• It reduces the incidence of water-borne pests, diseases and root rot, and reduces leaching of nutrients.

(d) Two sources of soil nitrogen [2 marks]

• Fixation of atmospheric nitrogen by leguminous plants (Rhizobium bacteria) and lightning.
• Decay of organic matter (plant residues, animal dung) and application of nitrogenous fertilizers.