For testing in LRRs W, X, and Y.
A mineral layer 10 cm (4 inches) or more thick, starting at a depth ≤30 cm (12 inches) from the surface, that has a matrix value of 4 or more and chroma of 2 or less and that within 30 minutes becomes redder by one or more Munsell unit in hue and/or chroma when exposed to air.
User Notes: The soil should be at or near saturation when examined. Care must be taken to immediately obtain an accurate color of the soil sample upon excavation. The colors should then be closely examined again after several minutes. Do not allow the sample to begin drying, as drying will result in a color change. Care must be taken to closely observe the colors. As always, do not obtain colors while wearing sunglasses. Colors must be obtained in the field under natural lighting and not under artificial light. Also, look for the presence of other indicators.