An Umbrisol is a type of soil. The Food and Agriculture Organization define the group as those having a thick, acid topsoil rich in organic matter. This soil type is dominant in north-west Spain, parts of north-west United States and in parts of the Andes. There are about 1,000,000km^2 of umbrisols in the world, making it the 24th most common soil of 30 recognised in the 1998 classification World Reference Base for Soil Resources.

References

• Umbrisol Data and definition from the FAO