ZIMSEC O Level · Agriculture · Form 2, Form 3
Maize – Zimbabwe's staple crop
- Climate: warm temperatures and 500–800 mm of rain or more, well distributed.
- Land preparation: plough or prepare planting basins, then harrow to a fine tilth.
- Planting: after effective rains (from about mid-November); use certified hybrid seed suited to the region; common spacing about 90 cm between rows and 30 cm in the row.
- Fertiliser: Compound D at planting; ammonium nitrate top dressing at about 4–6 weeks.
- Weeding: early weeding is critical in the first six weeks.
- Pests and diseases: fall armyworm, maize stalk borer, maize streak virus.
- Harvesting and storage: harvest when grain is dry; treat with grain protectant; store in clean, dry, ventilated places to prevent weevils and the larger grain borer.
Other crops
- Groundnuts and soya beans (legumes): fix nitrogen, good in rotation.
- Sorghum and millet: drought-tolerant small grains for drier regions.
- Tobacco, cotton: cash crops.
Crop rotation
Growing different crops on the same land in sequence (e.g. maize → groundnuts → sorghum). Benefits: controls pests and diseases, maintains fertility, makes better use of nutrients at different depths.
Exam tip: In crop production questions, follow the order: land preparation → planting → fertilising → weeding → pest control → harvesting → storage.
Check yourself
- Why are legumes included in crop rotations?
- When is ammonium nitrate applied to maize?
- Name two pests of maize.
Show answers
- Their root nodules fix nitrogen, improving soil fertility for the next crop.
- As a top dressing about 4–6 weeks after emergence.
- Any two: fall armyworm, stalk borer, cutworms, weevils (in storage).
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