Theory question 102
Irrigation and Drainage(a) State five factors that should be considered in choosing an irrigation system in West Africa.
(b) Mention four problems associated with irrigation in West Africa.
(c) A rectangle-shaped farmland has a length of 0.4 km and a breadth of 2,400 m, calculate the area of the farmland in hectares.
(d) List one primary tillage and three secondary tillage implements. Primary tillage implement: Secondary tillage implements:
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(a) Any five: source and quantity of water; topography/slope of the land; soil type (infiltration, drainage); type of crop; cost of the system/capital; climate (evaporation); available labour and skill; size of farm.
(b) Any four: high cost of installation and maintenance; waterlogging; salinity/salt build-up; spread of water-borne diseases (bilharzia, malaria); soil erosion; shortage of water/skilled staff; weed growth.
(c) Length = 0.4 km = 400 m. Area = 400 m × 2,400 m = 960,000 m². In hectares: 960,000 ÷ 10,000 = 96 ha.
(d) Primary: disc plough (or mouldboard plough, chisel plough). Secondary (three): harrow; ridger; rotavator; cultivator.
Convert km to m before multiplying; 1 ha = 10,000 m².