Soil profiles are described according to the different soil layers that may be identified within each profile. These layers are called master horizons, and are allocated one or more letter codes, each of which has a specific meaning. The capital letters A, B, C, R, are used to designate master horizons in classifying the soils of the UAE.
A horizons are mineral soil horizons that show an accumulation of humified organic matter or show signs of cultivation.
B horizons are mineral soil horizons that show evidence of illuvial concentration of silicate clay, gypsum, carbonates, iron, aluminum, humus, silica, or sesquioxides alone or in combination or have a structure other than a rock structure.
C horizons or layers lack the properties of the A or B horizons and may be little affected by pedogenic processes.
R layers are strongly cemented to indurated bedrock.