Question

In the universal soil loss equation (USLE): A=RKLSCP, the parameter 'S' stands for

• A. Channel slope
• B. Steepness of slope factor
• C. Length of slope factor
• D. Average channel length

Hint:

USLE factors: $R$ = Rain erosivity, $K$ = Soil erodibility, $L$ = Length of slope, $S$ = Steepness of slope, $C$ = Crop cover, $P$ = Practice.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Wischmeier and Smith's Universal Soil Loss Equation (USLE) models average annual sheet and rill soil loss using six primary erosion factors.
Key Formula or Approach:
\[ A = R \cdot K \cdot L \cdot S \cdot C \cdot P \]
where \(S\) is the slope steepness factor.

Step 2: Detailed Explanation:
The individual parameters of USLE are:
- \(A\): Computed average annual soil loss (tons/ha/year)
- \(R\): Rainfall and runoff erosivity index
- \(K\): Soil erodibility factor
- \(L\): Slope length factor (ratio of soil loss to standard 22.13 m length)
- \(S\): Slope steepness factor (ratio of soil loss to standard 9% slope gradient)
- \(C\): Cover and management factor
- \(P\): Conservation support practice factor
Thus, 'S' denotes the Steepness of slope factor.

Step 3: Final Answer:
Hence, parameter 'S' stands for Steepness of slope factor, corresponding to option (B).