Crop Production and Husbandry: From Seedbed to Store
This domain tests whether you can plan a crop from land preparation through to storage, and justify each decision: variety choice, seed rate, plant population, fertiliser timing, weed, pest and disease control, and post-harvest handling. The crop list is the one used in the syllabus: sorghum, maize, pearl millet, cowpea, groundnut and sunflower, plus horticultural crops such as tomato and cabbage.
What examiners look for
- Land preparation: clear the site, incorporate crop residues, break any hardpan, and level the seedbed so seed is placed at uniform depth.
- Seed quality: germination percentage and purity determine seed rate; certified seed outperforms retained seed.
- Spacing: row and in-row spacing fix plant population, which in turn fixes yield potential, weeding method and fertiliser dose.
- Planting depth: small seeds shallow (1–2 cm), maize and sorghum 3–5 cm; deeper in dry sand, shallower in clay.
- Inputs: basal fertiliser at planting, nitrogen top dressing at 4–6 weeks, weeding at about 2 and 5 weeks.
- Rotation: cereal after legume interrupts pests and restores nitrogen.
Worked example: seed rate
Maize is planted at 75 cm between rows and 30 cm within the row. Area per plant = 0.75 × 0.30 = 0.225 m², so population = 10 000 ÷ 0.225 = 44 444 plants/ha. At a 1000-grain weight of 250 g, that seed weighs 44 444 × 0.25 g = 11.1 kg. Allowing 90% field germination, seed rate = 11.1 ÷ 0.90 = 12.3 kg/ha. The reasoning runs population first, then seed weight, then the germination correction, and each step carries marks.
Traps
- Quoting a seed rate without linking it to population and germination.
- Treating seed rate and plant population as the same number.
- Putting all nitrogen at planting, so it leaches or volatilises before the crop needs it.
- Ignoring the pre-harvest interval when spraying close to harvest.