Question

Trees and shrubs commonly planted in rows at right angles to the prevailing winds are called:

• A. Shelterbelts
• B. Terrace cultivation
• C. Strip cropping
• D. Mulching

Hint:

Shelterbelts (windbreaks) are highly effective biological measures used in arid and semi-arid regions to reduce wind velocity and combat wind erosion by planting trees perpendicular to wind direction.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Soil conservation involves implementing biological and mechanical measures to protect the soil from degradation, specifically water and wind erosion.
Wind erosion is a major threat in arid, semi-arid, and coastal regions, where high-velocity winds lift and transport fertile topsoil particles.
To reduce wind velocity near the ground surface and protect agricultural fields, vegetative barriers are strategically established across the path of the prevailing winds.

Step 2: Detailed Explanation:
Let us analyze the definitions and functions of each listed conservation practice:
1. Shelterbelts (or Windbreaks):
Shelterbelts are wide, systematically arranged barriers of living trees and shrubs planted in multiple rows at right angles to the direction of the prevailing erosive winds.
As the wind passes through the shelterbelt, the dense canopy of leaves and branches acts as a physical barrier, deflecting the wind upward and significantly reducing its velocity near the ground.
This reduction in wind speed protects the soil from wind erosion, reduces moisture loss from evapotranspiration, and protects delicate crops from mechanical damage.
Typically, a shelterbelt consists of tall, medium, and short species in a triangular cross-section to maximize wind deflection.
Therefore, this definition matches the question.
2. Terrace Cultivation:
This is a mechanical soil conservation measure used on steep hill slopes, where the slope is cut into a series of flat steps or benches to reduce water runoff and soil erosion, not wind velocity.
3. Strip Cropping:
This is an agronomic practice where erosion-permitting crops (like maize or cotton) and erosion-resisting crops (like legumes or grasses) are grown in alternating strips across the slope to intercept runoff water, rather than wind.
4. Mulching:
This is the practice of covering the soil surface with organic or inorganic materials (like crop residues or plastic sheets) to conserve soil moisture, regulate soil temperature, and suppress weeds.

Step 3: Final Answer:
Thus, the vegetative rows of trees and shrubs planted at right angles to the prevailing winds are called Shelterbelts.