Ch. 12
) The main "type" of water that plants use is ________.
capillary
After gravitational water has drained away, ________ is the water that remains in the soil and is available for use by plants.
capillary water
Air within the soil is usually highly saturated and rich in ________.
carbon dioxide
) Like ________, humus is a catalyst for chemical reactions and a reservoir for plant nutrients and soil water.
clay
In the soil, which of the separates are associated with significant chemical activity in soil?
clay
The smallest-sized pieces of a soil are ________.
clays
Earthworms ________.
EXCRETE CASTS
The following is not an important soil microorganism
earthworm
) For all soil orders, the surface layer is the ________.
epipedon
Globally, the influence of this soil-forming factor fades with time.
GEOLOGIC
Parent material is closely associated with which soil-forming factor
GEOLOGIC
________ is a measure of the ease with which water moves through the soil
Permeability
Which of the following horizons is found furthest from the surface of the soil
R
The weathered layer of loose inorganic material overlaying unfragmented rock below is __
REGOLITH
Much soil material is actually wasted bits of rocks and composed of ________.
SILICA
The B horizon is usually called ________.
SUBSOIL
Which pH reading is suitable for most plants and soil microorganisms
7
) Based on the pH scale soils are neutral at ________
7.0
Organic matter usually comprises about ________ percent of total soil volume
5
The cation exchange capacity is most closely associated with ________
B) colloids
Which of the following is NOT a property of soil clay? 45) A) occurs as thin laminar sheets B) made primarily of silt C) colloidal in size D) It is able to hold water to itself. E) Many chemical reactions occur on its surfaces.
B- MADE PRIMARILY OF SILT
The soil-forming factor which is said to make soil more than "just dirt" is the ________ factor.
BIOLOGICAL
The unconsolidated parent materials beneath the level of roots is called the ________ horizon of soil.
C ---------- (LITERALLY THE LETTER)
Which of the following represents an addition to soil water
percolation
Which is NOT a main soil-forming factors? A) geologic B) climatic C) human activity D) chronological E) topographic
C. HUMAN ACTIVITY
________ is least available to plants because it is held in chemical combination with the minerals in the soil
Combined water
Three-quarters of the soil's metabolic activity is generated by ________
E) microorganisms
Earthworms ________.
INCREASE SOIL POROSITY
Soils are considered part of the...
LITHOSPHERE
________ is a soil texture in which none of the three main soil separates dominates the other two
Loam
Among layers of the soil horizon, the one with the most organic material is ________.
O
In terms of topography, the deepest soils are ________.
ON FLAT LAND
Most soil development takes place ________.
ON SCALES OF TIME LONGER THAN HUMAN LIFE SPANS
Which of the following NOT a reason earthworms increase the fertility of the soils in which they reside?
Stimulation by plowing for agriculture
The processes that deepen and age soils include all but the following
TAXONOMY
The true soil layer is known as ________.
THE SOLUM
) ________ brings soil materials from the A horizon to the B horizon.
Translocation
Gravitational water is ________.
a temporary form of soil moisture
The difference between field capacity and the wilting point is called ________.
available soil moisture
The minerals that form cations are known as ________.
bases
On the standard pH scale, the number 10 indicates a ________ soil
basic
) A soil with a high cation exchange would likely be ________.
fertile
Which of the following is NOT true of soil air
full of nutrients
Humus has a consistency not unlike that of ________.
gelatin
Which of the following terms is usually confused with but is not directly descriptive of soil moisture
groundwater
This type of water is held to soil particles by adhesion and is normally unavailable to plants.
hygroscopic water
Dead plant parts are known as ________ when they accumulate on the surface of the soil.
litter
Which of the following is NOT considered part of the soil?
living plants
The laminar sheets which are clay particles are ________.
negatively charged
Soil structure is usually determined by clumps called ________.
peds
Roughly one half of the volume of an "average" soil type is composed of ________
pore spaces
The measure of a soil's capacity to hold water and air is called ________.
porosity
A soil with a large percentage of clay would be ________ and ________
porous, non-permeable
Humus is associated with ________
rotted and rotting plant and animal remains
) The size groups within the standard classification of soil particle sizes are termed ________
separates
Several soil horizons together make up a ________.
soil profile
The dynamic relationship between precipitation and evaporation in any given location is the ________.
soil-water balance
In terms of a typical soil-water balance in Most of the United States, which season is associated with a soil water surplus?
spring
A major determinant of a soil's water holding capacity is its ________
structure
The term "clay" is a reference to ________
texture
