Farm Machinery, Implements and Post-Harvest Handling
What the exam asks
Farm Machinery, Implements and Post-Harvest Handling tests implement function, field capacity, power matching, threshing and cleaning, drying, storage and quality loss. Numeric items often ask for area covered per hour or storage moisture.
Core rules
- Tillage implements prepare soil; sowing implements place seed; harvesting cuts crops; threshing separates grain from earhead; winnowing cleans grain with air; drying lowers moisture for safe storage.
- Theoretical field capacity = working width × forward speed, with consistent units. Effective field capacity = theoretical capacity × field efficiency.
- Safe storage requires dry grain, clean bags, a moisture-proof store and pest control. Grain moisture above the safe limit invites mould, insects and heating.
- Post-harvest losses occur at harvesting, threshing, cleaning, drying, transport and storage; timely operations reduce them.
- Machines must match farm size and power; an oversized machine raises fixed costs, while an undersized one delays operations.
Worked example
A seed drill has a 2 m working width and travels at 5 km h−1. Theoretical area per hour = 2 m × 5,000 m h−1 = 10,000 m2 h−1 = 1 ha h−1. If field efficiency is 80%, effective capacity = 1 × 0.80 = 0.8 ha h−1. Reasoning: convert speed to metres per hour and divide by 10,000 m2 per hectare. For 12 ha, time = 12 ÷ 0.8 = 15 hours of field work, excluding turning and refilling delays already reflected in efficiency.
Traps
Do not confuse theoretical with effective field capacity; do not thresh at high moisture and then expect safe storage; winnowing is not threshing. A heavier machine is not always better. Safe moisture limits differ by crop and storage duration.