(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 and three secondary tillage implements
Explanation
(a) Factors considered in choosing an irrigation system in West Africa
- Cost of irrigation system
- soil type
- availability ofwater
- topography/slope of land
- type of crop to be cultivated
- size of farmland
(b) Problems associated with irrigation in West Africa
- Irrigation equipment is expensive to install
- Inadequate water supply for irrigation in certain areas and periods
- Maintenance cost is high
- Inadequate technical know
- how on the use of irrigation schemes among farmers
- The high relative humidity on irrigated land favours the growth of disease-causing organisms
- Salts that are toxic to crops could be introduced to the farmland through irrigation water
- Some irrigation systems disturb free movement of farm machinery
- Damage of source of water supply may render the irrigation system ineffective or cause destruction of immediate environment
- Water loving plants are likely to proliferate as a result of moisture in the soil leading to weed infestation
(c) Area of farmland in hectares Length = 0.4km = 400m lmk
Breath = 2,400m
Area of rectangle = length x breath lmk
Area of farmland 400m x 2,400m = 960,000m\(^2\) lmk
1 Hectare = 10,000m\(^2\) Area of farmland in hectares = \(\frac{960 000}{10,000}\) Imk
= 96 hectares lmk
(d) Primary and secondary tillage implements
Primary tillage implement
Plough/mouldboard plough/disc plough/chisel
plough 1mk
Secondary tillage implemens
- harrow/disc harrow ridger
- cultivator
- rotavator