Agronomic & Mechanical Erosion Control Structures: Contour Farming, Strip Cropping, Bunding, Terracing & Graded Channels

• Pneumatic Tyre Aspect Ratio Classifications:
• Aspect Ratio ($AR$) of a tractor tyre is the ratio of section height ($H$) to section width ($W$) expressed as a percentage or fraction ($AR = H / W$):
• Low-section (low-profile) tyres: $AR \lt 0.75$
• Standard agricultural tractor tyres: $AR = 0.80 - 0.85$
• High-molded (tall-profile / high-aspect) agricultural tyres: Have tall, narrow carcass sections designed for high ground clearance and crop row spacing where $AR \ge 1.00$ (1.00 or higher).
• Conclusion: 1.00 or higher (Option 4).

Correct option: (4) 00 or higher

• Tractor Operator Seat Ergonomics and Ride Vibration:
• Ride vibration in agricultural tractors consists of pitch, roll, and vertical bounce vibrations induced by terrain roughness.
• The Centre of Gravity (CG) of the tractor experiences the minimum angular rotational acceleration and pitch motions.
• Positioning the operator's seat as near to the centre of gravity as practical isolates the driver from severe pitching and rolling whiplash amplitudes.
• Conclusion: Near to the centre of gravity (Option 2).

Correct option: (2) Near to the centre of gravity

• Furrow Opener Geometrical Classifications:
• Furrow openers in seed drills are categorized by the angle made with the soil surface:
• Acute angle openers: Penetrate by suction/cutting (e.g., Hoe type, Shovel type).
• Right angle openers: Vertical penetration (e.g., Double disc type).
• Obtuse angle openers: The cutting edge slopes backward forming an obtuse angle with the direction of travel, sliding over crop residues and trash without clogging (e.g., Stub runner type, curved runner).
• Conclusion: Stub runner type (Option 3).

Correct option: (3) Stub runner type

• Threshing Cylinders for Fine Straw (Bhusa) Production:
• In Indian agriculture, wheat straw (bhusa) is heavily valued as dairy cattle fodder and must be bruised and crushed into fine pieces.
• The Hammer mill type (or syndicated beater type with serrated concave) threshing cylinder uses high-speed swinging/fixed hammers that pulverize and bruise wheat straw into exceptionally fine fodder.
• Rasp-bar and spike-tooth cylinders thresh grain effectively but produce coarser straw pieces.
• Conclusion: Hammer mill type (Option 2).

Correct option: (2) Hammer mill type