Farm Machinery, Implements and Post-Harvest Technology
Farm Machinery, Implements and Post-Harvest Technology - This domain tests tillage implements, sowing and harvesting machinery, threshing, drying, storage and grading.
Core rules
- Primary tillage: mouldboard plough and disc plough; secondary tillage: harrow, cultivator and leveller.
- A seed drill places seed and fertilizer at the correct depth and spacing; calibration prevents over- or under-seeding.
- Field capacity: theoretical capacity = (width × speed) ÷ 10 for ha/h when width is in metres and speed in km/h; effective capacity is lower.
- Threshing separates grain from straw; combine harvesters do harvesting and threshing together.
- Safe storage moisture: wheat about 12%, paddy 13–14%; dry to safe moisture before storage.
- Storage: clean, dry, airtight bins; fumigation and aeration control insects and mould.
Worked example
An implement is 3 m wide and travels at 5 km/h. Theoretical field capacity = (3 × 5) ÷ 10 = 1.5 ha/h. At 80% field efficiency, effective capacity = 1.5 × 0.80 = 1.2 ha/h. Reasoning: the formula gives area covered per hour; field efficiency accounts for turns, refilling and breaks.
Traps
- Do not report theoretical capacity as actual field capacity.
- Grain moisture is usually expressed on a wet basis; do not mix wet and dry basis.
- A mouldboard plough is primary, not secondary, tillage.
- Storing damp grain causes heating, mould and insect attack.
- A thresher does not clean grain completely; winnowing or a cleaner is still needed.