Variables in the Wind Erosion Equation (WEQ, Woodruff and Siddoway, 1965: $E = f(I, K, C, L, V)$):

• $I$: Soil erodibility index (expressed as potential soil loss in tonnes/ha/year from an isolated, level, smooth, unsheltered field based on percentage of non-erodible aggregates $\gt 0.84\text{ mm}$).
• Soil erosivity relates to kinetic energy of rainfall/wind.
• Wind velocity is captured in the climatic factor ($C$).
• Wind duration is part of the climatic factor ($C$).
  
  Option breakdown:
• $I$ stands for soil erodibility index.
• Erosivity is climate/force related.
• Wind velocity is part of $C$.
• Wind duration is part of $C$.

Saline-alkali soils possess characteristics of both saline and alkali soils: $\text{EC} \gt 4.0\text{ dS/m}$, $\text{ESP} \gt 15$, and $\text{pH} \gt 8.5$ (variable depending on salt concentration). Option analysis: (A) Saline soils have $\text{EC} \gt 4.0$, $\text{ESP} \lt 15$, $\text{pH} \lt 8.5$. (B) Alkali soils have $\text{EC} \lt 4.0$, $\text{ESP} \gt 15$, $\text{pH} \gt 8.5$. (C) Degraded alkali soils undergo leaching of salts with acid upper horizon. (D) Saline-Alkali soil has both high salinity and high exchangeable sodium.

According to Hans Jenny ($1941$), soil formation factors are $S = f(cl, o, r, p, t)$. Active factors supply energy to act on the soil system: Climate ($cl$) and Organisms/Biosphere ($o$). Passive factors are Parent material ($p$), Relief/Topography ($r$), and Time ($t$). Option analysis: (A) Time and Relief are passive factors. (B) Climate and Organisms are the active factors. (C) Time is passive. (D) Parent material is passive.