Curtis F. Marbut

Curtis Fletcher Marbut (1863–1935) served as Director of the Soil Survey Division of the U.S. Department of Agriculture from 1913 until his death in 1935.

Marbut developed the first formal soil classification scheme for the United States.

In 1927 he published a translation of Glinka's The Great Soil Groups of the World and their Development from German to English.

At the highest level of classification the soils were divided into pedocals and pedalfers.

The pedalfers began about at the udic border and referred to soils rich in aluminium (alumen) and iron (ferrous).