Question

In Wind Erosion Equation, \( E = f(I \times K \times C \times L \times V) \), I denotes

• A. Soil erodibility index
• B. Soil surface roughness
• C. Climatic factor
• D. Vegetative cover

Hint:

Memorize the WEQ variables:
I - Index of erodibility.
K - Knobs/Ridges (Roughness).
C - Climate.
L - Length of field.
V - Vegetation.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question requires identifying the components of the "Wind Erosion Equation" (WEQ), a standard model used to estimate soil loss due to wind.
Key Formula or Approach:
The Wind Erosion Equation developed by Chepil and Woodruff (1963) is expressed as:
\[ E = f(I, K, C, L, V) \]
Where:
\( E \) = Potential average annual soil loss.

Step 2: Detailed Explanation:

• Component Breakdown:
\( I \) (Soil Erodibility Index): This refers to the potential soil loss from a wide, bare, smooth, and unsheltered field. It is based on the percentage of non-erodible soil aggregates (greater than 0.84 mm).
\( K \) (Soil Ridge Roughness Factor): This accounts for the surface roughness caused by tillage ridges. Rougher surfaces reduce wind speed at the ground level.
\( C \) (Climatic Factor): This involves wind speed and soil moisture. Drier conditions and higher wind speeds increase \( C \).
\( L \) (Unsheltered Distance): The length of the field in the direction of the prevailing wind. Longer fields allow more "saltation" and soil movement.
\( V \) (Vegetative Cover): This accounts for the amount, type, and orientation of vegetative residue on the surface.

• Importance of \( I \):
The Soil Erodibility Index is the most fundamental factor.
It defines the soil's inherent vulnerability.
Sandy soils have a high \( I \), while well-aggregated clayey soils have a lower \( I \).

• Application:
Engineers use this equation to design shelterbelts and determine which tillage practices will minimize wind-induced topsoil loss.

Step 3: Final Answer:
In the functional relationship for wind erosion, the letter \( I \) represents the Soil Erodibility Index.