Soils Chapter 7
An epipedon
Is a surface horizon
A soil pedon is ____.
a three-dimensional unit that embodies the primary characteristics of an individual soil
Means low base saturation (nutrient poor)
dystr
Refers to the particle size
fine-loamy
Investigating the soils of northern Canada in 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?
Cryent
Aridic in a soil name means
Dry
In which soil orders would recent alluvium most likely be a common parent material?
Entisols
Soils classified as Inceptisols have the least well developed profiles of those in any order in the Soil Taxonomy system.
False
arg is a formative element in the U.S. Comprehensive Soil Classification System that means
Has a Bt horizon
Consider an entisol
Is a recently formed soil with little profile development
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 argillic horizon is a diagnostic horizon characterized by the subsurface accumulation of silicate clays.
True
You would be more apt to find a Gelisol in Alaska than in Iowa.
True
A thick surface soil horizon that is dark colored and has a low base saturation is most likely to be a(n)
Umbric epipedon
Refers to the soil temperature
mesic
A horizon that is a light colored E horizon is most likely to be a(n)
Albic horizon
An illuvial clay horizon is most likely to be a(n)
Argillic horizon
In soils of which great group would you most likely find wide surface cracks during periods of dry weather?
Calciusterts
Soils in which of the following suborders would be more likely to occur in Minnesota than in Texas?
Cryolls
A pedon is a 3 dimensional field unit occupying about 1000 square meters (1 hectare) of land area.
False
Epipedons are diagnostic subsurface horizons that are one of the primary means of classifying soils in the United States.
False
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.
False
Soil Taxonomy, the classification system used in the United States, was developed by C. E. Marbut and associates in the 1940s.
False
Spodosols are generally less acidic and less sandy than are Alfisols
False
The categories of Soil Taxonomy can be listed from the broadest (first) and most specific (last) as: order, suborder, great group, subgroup, series, family.
False
A brittle horizon is most likely to be a(n)
Fragipan
Consider a spodosol
Has a spodic horizon
alb is a formative element in the U.S. Comprehensive Soil Classification System that means
Has an albic horizon
A horizon that is organic with a very low density is most likely to be a(n)
Histic epipedon
Consider an inceptisol
Is embryonic with few diagnostic features
fluv is a formative element in the U.S. Comprehensive Soil Classification System that means
Is from flowing water
sapr is a formative element in the U.S. Comprehensive Soil Classification System that means
Is in most decomposed stage
xer is a formative element in the U.S. Comprehensive Soil Classification System that means
Is of a dry environment
ud is a formative element in the U.S. Comprehensive Soil Classification System that means
Is of a humid environment
Which of the following soil temperature regimes would provide the warmest and least variable soil temperatures?
Isohyperthermic
Consider an alfisol
Many have an argillic horizon
Aquic in a soil name means
Means wet
A surface horizon that is thick, dark colored, and has high base saturation is most likely to be a(n)
Mollic epipedon
A soil sample from an A horizon in W. MI. with a bulk density of 1.33 Mg/m3 is
Possibly from a cultivated soil
psamm is a formative element in the U.S. Comprehensive Soil Classification System that means
Sandy
Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates
Spodosols
The nomenclature of Soil Taxonomy is characterized by all but which one of the following statements?
The names give a clear indication of the modes of genesis of the soil.
An aquic soil moisture regime connotes a higher degree of soil moisture saturation than an ustic one.
True
Histosols generally have higher organic matter contents than Mollisols.
True
Mollisols are characterized by a thick epipedon that is high in organic matter.
True
Oxisols are more highly weathered than are the soils of any other order.
True
The broadest category of classification in Soil Taxonomy specifies 12 soil orders, 11 of which are for mineral soils.
True
The name of a great group also indicates the order and suborder of which it is a member.
True
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.
True
Vertisols are characterized by high contents of swelling-type silicate clays.
True
Argillic horizons are characterized by ___.
accumulation of silicate clays
This formative element refers to the ratio of CEC to %clay
active
Which of the following diagnostic horizons would likely not restrict root growth in soils?
albic
Which soil moisture regime has the highest soil moisture levels?
aquic
Means high base saturation (nutrient rich)
eutr
Means minimum horizon development
hapl
Refers to the mineralogy of the soil
mixed
Which of the following subsurface diagnostic horizons would you expect to find in a highly weathered soil of the humid tropics?
oxic
Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties?
series
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?
udolls