Write a geographical account of irrigation farming in Nigeria under the following headings: (a) Factors that favour the type of agriculture (b) Major farmin...

Answer Details

Irrigation farming is the artificial supply of water to farmland to grow crops. In Nigeria it is practised mainly in the drier northern states, where rain-fed farming alone cannot support cultivation throughout the year.

(a) Factors that favour the type of agriculture

• Very high temperatures throughout the year, giving long growing seasons and strong sunshine for crop ripening.
• Dry conditions with low annual rainfall (often less than 75 cm, e.g. the Sokoto and Chad basins), which makes rain-fed farming unreliable and creates the need to irrigate.
• Short wet season (only about four months), so water must be stored and applied artificially during the long dry season.
• Low relative humidity in the north, which reduces crop disease and suits irrigated cereals and vegetables.
• Development of large-scale irrigation schemes and dams (Tiga, Kainji, Bakolori, Goronyo, Challawa) that store water and feed canals for dry-season farming.
• Presence of perennial rivers and fertile alluvial (fadama) soils along the Niger, Benue, Sokoto-Rima, Hadejia and Yobe valleys, providing both water and rich land.
• Extensive flat land suited to gravity canal irrigation, and government support through the River Basin Development Authorities.

(b) Major farming areas and associated crops

(c) Problems

• Flooding of farmland when rivers overflow or when dams release excess water.
• Fluctuation in the level of water as rivers fall sharply in the dry season and reservoirs silt up, reducing the supply available for irrigation.
• Displacement of settlements and farmland when large dams and reservoirs are built.
• Disruption of the normal flow of rivers by dams, which affects downstream users and fisheries.
• Accumulation of mineral salts (salinisation) and waterlogging from poor drainage under intense evaporation, which lowers soil fertility.
• High cost of building and maintaining dams, canals and pumps, together with a shortage of technical manpower and the spread of water-borne diseases and pests.