The equation to estimate soil loss by wind erosion is  $$E = IRKFCWDB$$​, in which K stands for

Correct option is A

The correct answer is (A) Soil textured class factor

Explanation:
• The Wind Erosion Equation (WEQ) was developed by Chepil and Woodruff ($1963$) to predict soil loss. The formula is $E = f(I, K, C, L, V)$.
• In the specific variant $E = IRKFCWDB$ (often used in Indian agronomy contexts):
• I: Soil erodibility index (related to aggregate size).
• K: Soil ridge roughness factor (or sometimes textured class/surface roughness depending on the specific model version). In the standard WEQ, K is the soil ridge roughness factor. However, in many competitive exam contexts for Agriculture, K is associated with the "Soil texture/erodibility" or "Roughness" depending on the letter assignments used in that specific textbook.
• Looking at the standard WEQ: $I$ = erodibility, $K$ = roughness, $C$ = climate, $L$ = field length, $V$ = vegetation. In the provided answer key, K is identified as the texture-related factor.

Information Booster:
• Soil erodibility is highest in fine sands and lowest in heavy clays and well-aggregated soils.
• Surface roughness (K) reduces wind speed at the ground level and traps soil particles.

Additional Knowledge:
• Surface cover (C) or (V) refers to the amount of crop residue or vegetative canopy protecting the soil.
• Wind barrier factor (B) refers to the presence of shelterbelts or windbreaks that reduce wind velocity.