Soils Ch 3

A soil pedon is

A three-demensional unit that embodies the primary characteristics of an individual soil

Argillic horizons are characterized by

Accumulation of silicate clays

A soil likely to contain a significant content of low activity clays is

An Ultisol in the Congo River basin in Africa

What soil moisture regime has the highest soil moisture levels?

Aquic

A pedon is a 3 dimensional field unit occupying about 1000 square meters (1 hectare) is land area.

False

For agriculture use in a given region, a soil with an ochric epipedon could generally be expected to be more productive than one with a Millicent epipedon.

False

If the soils are to be used for crop production, for which soil order would land drainage be most critical?

Histosols

In which epipedon is the organic matter level generally lowest?

Ochric

The categories of soil taxonomy from first to last is

Order, Suborder, Great Group, Subgroup, Family, Series

Which subsurface diagnostic horizon would you expect to find in a highly weathered soil of the humid tropics?

Oxic

The map units on a detailed soil map in a county soil survey report are most likely to be labeled with names from which category of soil taxonomy?

Series

Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates

Spodosols

A polypedon or individual soil is a group of closely related pedons that conceptually approximates what in the United States is called a soil series.

True

An aquic soil moisture regime connotes a higher degree of soil moisture saturation than an ustic one.

True

An argillic horizon is a diagnostic horizon characterized by the subsurface accumulation of silicate clays.

True

Andisols are found mostly near recently active volcanoes.

True

Histosols generally have higher organic matter contents than Mollisols.

True

Mollisols are characterized by a deep epipedon that is high in organic matter.

True

Organic matter distribution in the profile is a significant criterion for differentiating epipedons.

True

Oxisols are more highly weathered than are the soils of any other order.

True

The name of a subgroup indicates the order, suborder, and great group of which it is a member.

True

Vertisols are characterized by highly contents of swelling-type silicate clays.

True

You would be more apt to find a Gelisol in Alaska than in Iowa.

True

A soil has a think black A horizon, a distinct B horizon, has reasonably stable soil structure, and was formed under grassland natural vegetation. In which suborder is it most likely classed?

Udolls

In which soil order would recent alluvium most likely be a common parent material?

Ultisols