While the USDA Web Soil Survey provides the USLE erodibility factor, $K,$ for many US soils, it does not cover all areas within the US nor soils outside of the US$.$ The equation shown below can be used to calculate $K$ as a function of percent organic matter, percent clay, percent silt, percent very fine sand, soil structure and soil permeability. Discuss why each of these variables are important to soil erodibility.

$K=\frac{2\mathrm{.}1E-14(12-OM)M^{1\mathrm{.}14}+3\mathrm{.}25(S_1-2)+2\mathrm{.}5(P_1-3)}{100}$

Where: