Agricultural Engineering and Farm Machinery
Domain 5: Agricultural Engineering and Farm Machinery
This domain tests farm power, implements, irrigation, structures, calibration and safety. Expect practical calculations and identification of the right machine or method for a task.
Core rules and concepts
- Tillage: primary tillage (plough) breaks and inverts soil; secondary tillage (harrow, cultivator) prepares a seedbed.
- Planting: seed drills meter seed and fertilizer; calibration prevents over- or under-sowing.
- Sprayer calibration: application rate depends on nozzle output, number of nozzles, walking speed and swath width.
- Irrigation: surface, sprinkler and drip systems differ in efficiency and suitability. Drip saves water but needs filtration.
- Safety: power take-off guards, hydraulic safety, chemical protective equipment and correct hitching.
Worked example
A boom sprayer has 4 nozzles, each delivering 1.2 L/min. Walking speed is 3 km/h and swath width is 2 m. Total flow = 4 × 1.2 = 4.8 L/min = 288 L/h. Area covered = 3,000 m/h × 2 m = 6,000 m²/h = 0.6 ha/h. Application rate = 288 ÷ 0.6 = 480 L/ha. The reasoning: convert minutes to hours and square metres to hectares before dividing; otherwise the answer is wrong by a large factor.
Traps that cost marks
- Forgetting to multiply by the number of nozzles.
- Mixing metres, centimetres and hectares.
- Confusing plough with harrow functions.
- Ignoring sprayer speed changes during calibration.