Deck 3: Soil Classification

Question 1

Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties?

A) series
B) suborder
C) order
D) family
E) great group

Answer 1

A

Question 2

The map units on a detailed soil map on Web Soil Survey are most likely to be labeled with names from which category of Soil Taxonomy?

A) order
B) suborder
C) great group
D) subgroup
E) series

Answer 2

E

Question 3

A soil has a thick 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?

A) udolls
B) ustalfs
C) cambids
D) aquents
E) udults.

Answer 3

A

Question 4

A soil pedon is ____.

A) a category of Soil Taxonomy
B) a three-dimensional unit that embodies the primary characteristics of an individual soil
C) generally larger in area than a polypedon
D) a diagnostic subsurface horizon prominent in arid regions and in sandy parent materials.
E) a surface horizon used to characterize soil suborders and great groups

Question 5

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

A) Mollisols
B) Inceptisols
C) Aridisols
D) Oxisols
E) Histosols

Question 6

Which of the following describes a soil likely to contain a significant content of low activity clays?

A) an Alfisol in New York
B) a Mollisols in Central Brazil
C) an Oxisol in Minnesota
D) an Ultisol in the Congo River basin in Africa
E) an Inceptisol in Mississippi

Question 7

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

A) cambic
B) oxic
C) natric
D) salic
E) spodic

Question 8

The nomenclature of Soil Taxonomy is characterized by all but which one of the following statements?

A) Soil names (except for series level) identifies major soil characteristics.
B) The names of the orders all end with the letters sols.
C) The subgroup name also tells you the great group, suborder, and order names.
D) The names give a clear indication of the modes of genesis of the soil.
E) The names are based on measurable properties and not on presumed modes of genesis.

Question 9

Which of the categories in the Soil Taxonomy system indicates properties that have implications for root growth as well as for the construction of building foundations?

A) suborder
B) family
C) series
D) great group
E) subgroup

Question 10

You are seeking a soil with high clay content but one that is not sticky when wet nor hard and cloddy when dry. In which of the following suborders would you most likely find this soil?

A) Udert
B) Ustalfs
C) Aquands
D) Ustox
E) Cambids

Question 11

Argillic horizons are characterized by ___.

A) accumulation of silicate clays
B) high level of Na+ ions
C) high levels of iron and aluminum oxides
D) impervious hardpan layers
E) organic matter accumulation

Question 12

Soils in which of the following soil suborders would most likely have a prominent E horizon under the A horizon?

A) Ustox
B) Udalfs
C) Orthents
D) Aquepts
E) Udolls

Question 13

In which of the following epipedons is the organic matter level generally lowest?

A) mollic
B) umbric
C) histic
D) ochric
E) melanic

Question 14

Which soil moisture regime has the highest soil moisture levels?

A) udic
B) ustic
C) aquic
D) aridic
E) xeric

Question 15

Which of the following diagnostic horizons would likely not restrict root growth in soils?

A) albic
B) fragipan
C) salic
D) placic
E) petrocalcic

Question 16

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

A) Mollisols
B) Andisols
C) Spodosols
D) Alfisols
E) Ultisols

Question 17

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

A) Ultisols
B) Entisols
C) Andisols
D) Alfisols
E) Aridisols

Question 18

Which of the following soil temperature regimes would provide the warmest and least variable soil temperatures?

A) Thermic
B) Mesic
C) Isomeric
D) Isohyperthermic
E) Hyperthermic

Question 19

Soil scientists from which country first conceived the idea that soils were natural bodies?

A) United States
B) France
C) Russia
D) Great Britain
E) Belgium

Question 20

Soils in which of the following suborders would be more likely to occur in Minnesota than in Texas?

A) Fluvents
B) Cryolls
C) Udalfs
D) Usterts
E) Cambids

Question 21

The categories of Soil Taxonomy can be listed from the broadest (first) and most specific (last) as: order, suborder, great group, subgroup, series, family.

Question 22

Soil scientists generally map the soils in a landscape by sampling the soil in ______.

A) pre-determined a grid-like geometric pattern of evenly spaced points
B) a computer-calculated pattern of random points
C) auger holes made mostly near expected soil boundaries
D) four soil pits, one dug in each corner of the area to be mapped
E) A and D

Question 23

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

Question 24

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.

Question 25

The two most significant characteristics of the classification system used in the United States are a unique system of terminology and focus on measurable soil properties as a primary basis for the classification.

Question 26

Russian scientists were the first to develop the concept of soils as natural bodies.

Question 27

Andisols are found mostly near recently active volcanoes.

Question 28

Soils in the Oxisols order are deeply weathered and have deep subsurface horizons of silicon oxide.

Question 29

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

Question 30

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

Question 31

In soils of which great group would you most likely find wide surface cracks during periods of dry weather?

A) Calciusterts
B) Albaqualfs
C) Argiaquolls
D) Kandiaquults
E) Haplustox

Question 32

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

Question 33

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

Question 34

Epipedons are diagnostic subsoil horizons that are one of the primary means of classifying soils in the United States.

Question 35

The broadest category of classification in Soil Taxonomy specifies 12 soil orders, 11 of which are for mineral soils.

Question 36

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

Question 37

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

Question 38

The soil and a soil are two extremes in the concept of soils that is basic to most classification schemes.

Question 39

Soils classified as Inceptisols have the least well developed profiles of those in any order in the Soil Taxonomy system.

Question 40

Investigating the soils of northern Canada on summer, you dig a soil pit easily though fairly uniform peat material until, at 75 cm deep, your shovel hits a layer that is frozen solid. Into which type of soil are you most likely digging?

A) Histosol
B) Cryent
C) Fibrist
D) Histel
E) Cryert

Question 41

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

Question 42

Because soil development is just beginning in Entisols, these soils are generally less variable in properties than are those in the Andisol or Ultisol orders.

Question 43

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

Question 44

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

Question 45

The family category focuses on properties affecting plant roots and suitability for engineering uses of soils.

Question 46

Spodosols are generally less acidic and less sandy than are Alfisols.

Question 47

Histosols generally have higher organic matter contents than Mollisols.