Exam 18: The Geography of Soils

Broadleaf trees tend to increase the acidity of soils.

The U.S. soil classification system has not been updated since the mid-1970s.

Soils high in clay content may swell significantly when they absorb water.

The phenomenon of desert expansion along the margins of semiarid and arid lands is known as

Between 1982 to 2007, there was actually a decrease in soil erosion on U.S. cropland.

In addition to designation of horizons, soil scientists also designate subhorizons, for instance, indicating human activity or presence of organic matter.

The branch of soil science that studies soil as a medium for sustaining the growth of higher plants is known as

Steep slopes tend to develop thicker soils than level ground.

A high cation-exchange capacity (CEC) tends to indicate poor soil fertility.

The branch of soil science that deals with the origin, classification, distribution, and description of soils is known as

The A horizon is also commonly called topsoil.

The O horizon is typically lacking in organic matter.

Which of the following human activities may make soils more prone to erosion?

In soil science, the term to describe the cohesion of soil particles is

Oxisols are not very fertile.

A roughly equal mix of sand, silt, and clay is called

Thawing of Gelisols caused by warming climates could result in the release of carbon dioxide and methane to the atmosphere.

Expandable clay soils, such as montmorillonite, characterize this soil order.

The horizon that is commonly called topsoil is the ________ horizon.

The multiyear period of severe wind erosion and soil loss occurred in the Great Plains during the 1930s is known as