highly erodible land
(11) (A) The term “highly erodible land” means land— (i) that is classified by the Soil Conservation Service as class IV, VI, VII, or VIII land under the land capability classification system in effect on December 23, 1985 ; or (ii) that has, or that if used to produce an agricultural commodity, would have an excessive average annual rate of erosion in relation to the soil loss tolerance level, as established by the Secretary, and as determined by the Secretary through application of factors from the universal soil loss equation and the wind erosion equation, including factors for climate, soil erodibility, and field slope. (B) For purposes of this paragraph, the land capability class or rate of erosion for a field shall be that determined by the Secretary to be the predominant class or rate of erosion under regulations issued by the Secretary. (C) Equations .— Not later than 60 days after the date of enactment of this subparagraph, the Secretary shall publish in the Federal Register the universal soil loss equation and wind erosion equation used by the Department of Agriculture as of that date. The Secretary may not change the equations after that date except following notice and comment in a manner consistent with section 553 of title 5 .