Question

Which of the following is an agronomical measure of erosion control?

• A. Bench terracing
• B. Contour bunding
• C. Graded bunding
• D. Strip cropping

Hint:

To easily differentiate soil conservation measures:
- If it involves moving soil, digging, or building structures (terracing, bunding, gully plugs), it is a mechanical measure.
- If it involves planting, cropping patterns, or mulching (strip cropping, cover crops, contour farming), it is an agronomical measure.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Soil conservation measures are used to control water and wind erosion.
These measures are broadly classified into three categories:
1. Agronomical Measures: Crop management practices that use vegetation to protect the soil surface and reduce runoff velocity.
2. Mechanical/Structural Measures: Engineering structures designed to reduce slope length, retain runoff, or divert water safely.
3. Forestry/Biological Measures: Afforestation and shelterbelt establishment.

Step 2: Detailed Explanation:
Let us classify each of the given options:
1. Bench terracing (A):
This is a mechanical measure where steep slopes are converted into a series of flat, step-like platforms.
It involves significant earthwork and soil excavation.
Therefore, it is a mechanical measure.
2. Contour bunding (B):
This is a mechanical measure that involves constructing earthen or stone embankments (bunds) along contour lines across the slope.
These bunds intercept runoff and encourage infiltration.
Therefore, it is a mechanical measure.
3. Graded bunding (C):
This is a mechanical measure similar to contour bunding, but the bunds are built with a slight longitudinal grade to divert excess runoff safely into a disposal channel.
Therefore, it is a mechanical measure.
4. Strip cropping (D):
This is an agronomical practice where erosion-permitting crops (such as maize, millet, or cotton) are grown in alternating strips with erosion-resisting cover crops (such as legumes, pulses, or grasses).
The dense cover crops slow down surface runoff, trap dislodged soil particles, and protect the soil from raindrop impact.
This is a purely agricultural crop management practice that does not require constructing engineering barriers.
Therefore, it is an agronomical measure.

Step 3: Final Answer:
Among the options, strip cropping is classified as an agronomical measure of erosion control.
Hence, the correct option is (D).