For use in LRRs W, X, and Y.

A mineral layer that has 10 percent or more hue of N, 10Y, 5GY, 10GY, 5G, 10G, 5BG, 10BG, 5B, 10B, or 5PB with value of 4 or more along root channels or other pores and that starts at a depth ≤30 cm (12 inches) from the soil surface. The matrix has a dominant hue of 5Y or redder.

User Notes: In a soil layer that is becoming anaerobic, reduced conditions will first occur where the soil microbes have an ample supply of organic carbon. Colder soils, such as those in Alaska, normally have a low content of organic carbon, so the microbes will congregate along the channels containing dead roots. Gley colors will first appear along these channels. In a soil layer that is not already dominated by gley colors, break open pieces of the soil and look closely at the root channels. Many of these will be very thin or fine. See if you can observe thin coatings along the channels that match the gley colors listed in the indicator. If they occur, they indicate that the soil experiences anaerobic conditions.