Agricultural Engineering
Agricultural Engineering
This domain tests farm power, tillage implements, seed drill calibration, threshing and machinery selection, with an emphasis on applying engineering calculations to field conditions.
Core rules
- Farm power sources include human, animal, mechanical, electrical and renewable energy.
- Primary tillage cuts and inverts soil, as with a mouldboard plough; secondary tillage breaks clods and levels soil, as with a harrow or cultivator.
- Draft is the force required to pull an implement; power is the rate of doing work and depends on draft and speed.
- A seed drill meters seed through tubes; calibration checks the actual seed delivered over a measured area.
- Threshing separates grain from chaff; cleaning removes foreign matter.
Worked example
A seed drill has an effective width of 2 m and travels 50 m. Area covered = 2 × 50 = 100 m² = 0.01 ha. If it collects 0.6 kg of seed, the seed rate = 0.6 ÷ 0.01 = 60 kg/ha. The reasoning is to convert the measured area to hectares before dividing the seed weight by area.
Mark-losing traps
- Mixing draft with power; draft is force, power includes speed.
- Using the full width of the drill when only part of it is metering seed.
- Forgetting to convert square metres to hectares in calibration.
- Classifying a cultivator as primary tillage when it is usually secondary.