For use in LRRs R, S, T, and U; for testing in LRRs K and L.

A layer with a value of 3 or less and chroma of 1 or less starting at a depth of 15 cm (6 inches) or less from the soil surface. At least 70 percent of the visible soil particles must be masked with organic material when viewed through a 10x or 15x hand lens. Directly below this layer, 5 percent or more of the soil volume has a value of 3 or less and chroma of 1 or less, and the remainder of the soil volume has value of 4 or more and chroma of 1 or less to a depth of 30 cm (12 inches) or to the spodic horizon.

User Notes: This indicator applies to soils with a very dark gray or black surface or near-surface layer that is typically less than 10 cm (4 inches) thick but has no thickness requirement and is underlain by a layer in which organic matter has been differentially distributed within the soils by water movement (fig. 27). The mobilization and translocation of organic matter result in splotchy coated and uncoated soil. Observed without a hand lens, the masked sand particles appear to be closer to 100 percent masked with organic material when moist. Masked sand grains can disappear quickly if a soil has been drained or disturbed.