The tractor: types, parts and working equipment
The tractor pulls, pushes, lifts and powers other machines. Types: 2-wheel (walking) tractors for small plots, 4-wheel tractors (2WD or 4WD) for most farms, tracked (crawler) tractors for wet or heavy soil, and narrow orchard tractors.
- Engine (usually diesel) – power in kW or hp.
- Transmission and clutch – choose speed and pulling force.
- PTO (power take-off) – a spinning shaft that drives implements like rotavators or balers.
- 3-point hitch with hydraulics – lifts, lowers and holds implements; the drawbar pulls trailers.
- ROPS / safety cab – roll-over protection.
Machines for soil, sowing, crop care and harvest
Soil preparation and fertilising
Primary tillage breaks and turns soil: mouldboard or disc plough, chisel plough. Secondary tillage makes a fine seedbed: harrow, cultivator, rotavator. Fertiliser spreaders and manure spreaders feed the soil.
Sowing and planting
A seed drill puts small seeds (wheat, rice) in continuous rows. A precision planter places single big seeds (maize, cotton) at exact gaps. Transplanters set seedlings (rice, vegetables).
Crop care
Sprayers (knapsack, boom, air-blast) apply pesticides or liquid fertiliser; drones spray small or hilly fields and take images to find sick plants. Weeders and irrigation systems (drip, sprinkler, pivot) also help.
Harvesting
The combine harvester does 4 jobs: cut → thresh → separate → clean. Others: reapers, potato diggers, cotton pickers, forage harvesters, balers.
Precision farming, autonomous tractors and livestock machines
- GPS guidance and auto-steer keep rows straight with 2–3 cm accuracy, so there is less overlap and less wasted fuel, seed and chemicals.
- Variable-rate machines change the amount of seed or fertiliser across the field using soil and yield maps.
- Autonomous tractors and robots work without a driver, watched by sensors and cameras.
- Livestock: milking machines and milking robots, milk cooling tanks, feed mixer wagons, automatic drinkers, ventilation and manure scrapers.
Choosing machines, field capacity and safety
Field capacity (ha/h) = working width (m) × speed (km/h) ÷ 10 × field efficiency (about 0.65–0.85, because of turns and refills).
Farmers choose by farm size, soil, crop, labour, cost, fuel use and soil health. Heavy machines can compact soil, so wide tyres, low pressure and fixed tracks (controlled traffic) help. Small farms often share or rent machines (custom hiring centres in India, cooperatives in Europe).
Safety
- Never ride on the implement or the drawbar; one seat, one person.
- Switch off the engine and PTO and remove the key before clearing a blockage.
- Use ROPS and the seat belt; drive slowly on slopes.
- Wear PPE (gloves, mask, goggles) when spraying; keep children away.
Key formulas and definitions
- Field capacity (ha/h) = width (m) × speed (km/h) ÷ 10 × efficiency
- Time (h) = area (ha) ÷ field capacity (ha/h)
- 1 hectare = 10,000 m²
- Combine: cut → thresh → separate → clean
- Primary tillage (plough) → secondary tillage (harrow) → sowing
- Before clearing a blockage: engine off, PTO off, key out
Worked examples
1. A seed drill is 3 m wide and moves at 6 km/h with efficiency 0.75. What is its field capacity?
3 × 6 ÷ 10 = 1.8 ha/h theoretical; × 0.75 = 1.35 ha/h.
2. How long will that drill take to sow a 27 ha field?
Time = 27 ÷ 1.35 = 20 hours.
3. A sprayer boom is 12 m wide and moves at 8 km/h, efficiency 0.7. How many hectares can it spray in a 6-hour day?
12 × 8 ÷ 10 × 0.7 = 6.72 ha/h; 6.72 × 6 = 40.32 ha.
Common mistakes
- Thinking a bigger machine is always better. Heavy machines compact soil and cost more than a small farm can pay back.
- Confusing a seed drill with a planter. A drill sows rows of small seeds; a planter places single seeds at exact gaps.
- Forgetting field efficiency. Real capacity is less than width × speed because of turning and refilling.
- Clearing a jammed PTO machine with the engine running. Always switch off and remove the key.