Tama -- Iowa State Soil
Tama Soil Profile
Surface layer: very dark brown
silty clay loam
series is considered one of the most productive of the soils in Iowa that
are used for agricultural purposes. It makes up about 825,000 acres in
east-central and eastern Iowa. The series was first identified in Black
Hawk County, Iowa, in 1917. It has been identified in 26 counties in Iowa.
It also has been identified in Illinois, Minnesota, and Wisconsin.
Tama soils formed in 48 or more inches of silty loess; under tall prairie grasses with a deep, fibrous root system; and under relatively humid climatic conditions. Over hundreds of years, the grasses have added organic matter to the soils, producing a relatively thick, dark surface layer. In some areas, erosion has significantly affected the properties of the soils. Eroded Tama soils have less total nitrogen and organic matter and more clay in the surface layer than uneroded Tama soils.