Question

38. The metering mechanism most commonly used for drilling of wheat is

• A. Internal double run type
• B. Cup feed
• C. Fluted roller
• D. Stationary opening

Hint:

For small-to-medium grains (wheat, barley, mustard), the fluted roller is the most widely adopted metering mechanism.
Adjusting the active length of the exposed fluted roller is the primary method to calibrate the seed rate in the field.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
A seed drill must meter and deliver a uniform flow of seeds from the main hopper down into the furrow openers.
The choice of seed-metering mechanism depends on the seed size, shape, fragility, and the desired seeding rate range.

Step 2: Detailed Explanation:
Let us evaluate the listed seed-metering mechanisms:
- Fluted roller: This mechanism consists of a corrugated or grooved metal/plastic cylinder rotating inside a small feed cup beneath the hopper seed opening.
As the fluted roller rotates, seeds are caught in the grooves (flutes) and are carried down into the seed tubes.
The seed flow rate can be adjusted in two ways: by sliding the fluted roller axially to vary the active length of the flutes exposed to the seed cup, or by changing the rotational speed of the feed shaft.
This mechanism is highly robust, self-cleaning, and provides an exceptionally uniform feed rate for medium-sized, free-flowing grains like wheat, barley, and oats.
It is the standard metering mechanism installed in almost all commercial wheat seed drills in India.
- Internal double run type: Features a double-sided wheel with internal feeding ribs, primarily used for sowing a wider variety of seed sizes (large seeds on one side, small seeds on the other), but is more expensive and complex than the fluted roller.
- Cup feed: Uses small cups attached to a rotating chain or disc to lift seeds from the hopper, used for larger or irregular seeds (like potatoes or peanuts) to prevent mechanical damage.
- Stationary opening: Uses a simple sliding plate to vary the opening size, which is highly prone to clogging and does not provide uniform metering for grain crops.

Step 3: Final Answer:
The fluted roller is the metering mechanism most commonly used for drilling of wheat.