Agricultural Engineering and Farm Machinery
Agricultural Engineering and Farm Machinery
This domain covers farm power, implements, seed drills, sprayers, irrigation systems, field capacity and soil and water conservation structures.
Core rules and concepts
- Farm power sources include human, animal, tractor, diesel engine, electric motor and renewable energy.
- Draft is the force required to pull an implement; power = force × speed, with consistent units.
- Theoretical field capacity = effective width × forward speed. Effective field capacity includes turns, loading and other lost time through field efficiency.
- Seed drill calibration checks seed delivery over a measured area or number of wheel turns.
- Irrigation efficiency includes conveyance, application and storage components. Drip and sprinkler systems can raise water-use efficiency.
Worked example
A seed drill has an effective width of 2 m and operates at 5 km/h with 80% field efficiency. Theoretical capacity = 2 m × 5,000 m/h = 10,000 m²/h = 1.0 ha/h. Effective capacity = 1.0 × 0.80 = 0.8 ha/h. Time to sow 5 ha = 5 ÷ 0.8 = 6.25 hours. Reason: speed must be converted from km/h to m/h, and field efficiency reduces the theoretical area covered.
Traps that cost marks
Forgetting to convert km/h to m/h; using total width instead of effective width; mixing theoretical and effective field capacity; ignoring unit conversions in power calculations; calibrating a sprayer with water when the product changes flow behaviour.