For use in all LRRs, except for N, Q, R, S, V, W, X, and Y, those using A7 (LRRs P, T, U, and Z), and MLRA 1 of LRR A.

A layer of mucky modified loamy or clayey soil material 10 cm (4 inches) or more thick starting at a depth ≤15 cm (6 inches) from the soil surface.

User Notes: “Mucky” is a USDA texture modifier for mineral soils. The content of organic carbon is at least 8 percent but can range to as high as 18 percent. The percentage required depends on the clay content of the soil; the higher the clay content, the higher the content of organic carbon required. For example, mucky sandy loam requires between 8 and 14 percent organic carbon.