Agricultural Engineering, Tools and Farm Machinery
This domain tests whether you can select, use, maintain and cost farm tools and machines safely, and calculate work rates and power requirements.
Tools and implements
Hand tools include hoes, cutlasses, forks, rakes and dibbers; implements are tractor-mounted or animal-drawn - plough, harrow, ridger, planter, sprayer, trailer. Know the function and adjustment of each: a mouldboard plough inverts soil, a disc harrow breaks clods, a seed drill meters seed at set depth and spacing. Simple machines - lever, pulley, wheel and axle, inclined plane - reduce effort in farm work.
Power, maintenance and safety
Power sources are human, animal, wind, water, engine and electric motor. Know that 1 hp ≈ 0.746 kW. Daily maintenance: check oil, coolant, tyre pressure, belts and filters; clean and oil hand tools and store them dry. Safety: guards on power take-off shafts, no loose clothing near moving parts, correct lifting, safe chemical handling and sprayer calibration.
Worked example
A boom sprayer has a 3 m width and travels at 5 km/h. Theoretical work rate = width (m) × speed (km/h) ÷ 10 = 3 × 5 ÷ 10 = 1.5 ha per hour. Derivation: 5 km/h = 5,000 m/h; 5,000 × 3 = 15,000 m²/h = 1.5 ha/h. If field efficiency is 75% (turning and filling), actual rate = 1.5 × 0.75 = 1.125 ha/h.
Traps that cost marks
Forgetting to convert km/h to m/h loses the unit. Report theoretical and actual work rates separately. Do not confuse hp with kW. A machine that is well maintained still needs calibration - output per nozzle changes with wear. Never describe removing a guard as a labour-saving improvement.