SOIL SCIENCE EXAM QUESTIONS AND
100% CORRECT ANSWERS!!
Name the major components of a typical, moist surface soil and give the percentage of each
component by volume.
Day 2 (lecture notes) for moist surface soil
Major components:
1. Mineral matter
2. Organic matter
3. Soil water
4. Soil air
-About 50% pore space and about 50% solids
-Of the solids, 45% of the soil will be minerals, the other 5% will be organic matter
-Of the pore space, 25% of the pore space will be air and the other 25% will be water
Mineral matter
Composed of particles ranging in size from submicroscopic to those too big for a man to lift,
accounts for the bulk of the dry mass of the soil and occupies some 40 to 60 perent of the soil
volume, usually 45 to 49 percent.
Organic matter
-It is dark brown to black in color, is derived from the remains of dead plants and animals that
have been decomposed or are being decomposed.
-It occurs in largest amounts in the surface of soil, but even there seldom accounts for more than
10 percent of the dry mass of the soil, usually 1 to 5 percent.
Soil water
-Or soil soultion reacts chemically and physically with the soil solids.
-As a consequence, it contains solutes dissolved from soil particles and perhaps suspended
particles themseves.
,Soil air
Gases in the soil air are the same as those in the atmosphere but their relative abundance may be
different.
Name three primary minerals that weather to form secondary clay minerals in the soils.
Day 3 and lab manual around page 6
1. Feldspars
2. Augite and Hornblende
3. Micas
Name the primary silicate mineral that is resistant to weathering and dominates the sand
and silt fractions of most soils.
Quartz (SiO2)
Name two minerals that are comparatively soluble in soil solutions and therefore easily
weathered.
1. Calcite - second most soluble
2. Gypsum - most soluble
Name three mineral properties that can be used to distinguish among several hand held
mineral species.
1. Appearance (color)
2. Hardness
3. Clevage or no clevage - micas
4. Fizz if presented with acid - calcite
5. Ability to streak - goethite and hematite
6. Luster or dull appearance
Define the term soil using each of the five soil forming factors in the definition.
Soils are dynamic, always changing bodies having properties that reflect the integrated effects of
CLIMATE (atmosphere) and BIOLOGICAL ACTIVITY (biosphere, biota) on the
unconsolidated remnants of rock, (lithosphere) often called PARENT MATERIAL, at the earth's
, surface. These effects are modified by the TOPOGRAPHY (relief) of the landscape, and of
course continue to take place with the passage of TIME.
Given that a soil will support plant growth, state the general characteristics the soil as a
medium for plant growth must possess.
Plants depend on the soil for certain essentials for growth:
1. A continuous supply of water
2. A variety of chemical elements called plant nutrients
3. Oxygen from the soil air which is required by roots of most plant species
4. Physical support
Given a soil monolith or two-dimensional vertical sketch of a soil, identify the following:
soil profile, soil solum, A horizon, B horizon, C horizon, R horizon, parent material,
regolith, soil pedon, surface soil, and subsoil.
Definitions below.
Soil horizon
Layers in the soil which are parallel to the soil surface. The physical characterstics are different
between each layer. The result of the weathering of materials due to the soil forming factors.
Soil profile
2D cross sectional view of the soil, a vertical section of soil through all its horizons and
extending to parent materials below, from the ground surface to the parent rock
Soil solum
The 3D soil body in which the effects of climate and biological activity are most pronounced. A,
E, and B horizons compose the soil solum and are impacted by water (climate) and biota. Being
changed because of active factors.
Soil pedon
3D soil unit with all character of soil (1 m square, 2 m depth). Smallest soil individual.
A horizon
100% CORRECT ANSWERS!!
Name the major components of a typical, moist surface soil and give the percentage of each
component by volume.
Day 2 (lecture notes) for moist surface soil
Major components:
1. Mineral matter
2. Organic matter
3. Soil water
4. Soil air
-About 50% pore space and about 50% solids
-Of the solids, 45% of the soil will be minerals, the other 5% will be organic matter
-Of the pore space, 25% of the pore space will be air and the other 25% will be water
Mineral matter
Composed of particles ranging in size from submicroscopic to those too big for a man to lift,
accounts for the bulk of the dry mass of the soil and occupies some 40 to 60 perent of the soil
volume, usually 45 to 49 percent.
Organic matter
-It is dark brown to black in color, is derived from the remains of dead plants and animals that
have been decomposed or are being decomposed.
-It occurs in largest amounts in the surface of soil, but even there seldom accounts for more than
10 percent of the dry mass of the soil, usually 1 to 5 percent.
Soil water
-Or soil soultion reacts chemically and physically with the soil solids.
-As a consequence, it contains solutes dissolved from soil particles and perhaps suspended
particles themseves.
,Soil air
Gases in the soil air are the same as those in the atmosphere but their relative abundance may be
different.
Name three primary minerals that weather to form secondary clay minerals in the soils.
Day 3 and lab manual around page 6
1. Feldspars
2. Augite and Hornblende
3. Micas
Name the primary silicate mineral that is resistant to weathering and dominates the sand
and silt fractions of most soils.
Quartz (SiO2)
Name two minerals that are comparatively soluble in soil solutions and therefore easily
weathered.
1. Calcite - second most soluble
2. Gypsum - most soluble
Name three mineral properties that can be used to distinguish among several hand held
mineral species.
1. Appearance (color)
2. Hardness
3. Clevage or no clevage - micas
4. Fizz if presented with acid - calcite
5. Ability to streak - goethite and hematite
6. Luster or dull appearance
Define the term soil using each of the five soil forming factors in the definition.
Soils are dynamic, always changing bodies having properties that reflect the integrated effects of
CLIMATE (atmosphere) and BIOLOGICAL ACTIVITY (biosphere, biota) on the
unconsolidated remnants of rock, (lithosphere) often called PARENT MATERIAL, at the earth's
, surface. These effects are modified by the TOPOGRAPHY (relief) of the landscape, and of
course continue to take place with the passage of TIME.
Given that a soil will support plant growth, state the general characteristics the soil as a
medium for plant growth must possess.
Plants depend on the soil for certain essentials for growth:
1. A continuous supply of water
2. A variety of chemical elements called plant nutrients
3. Oxygen from the soil air which is required by roots of most plant species
4. Physical support
Given a soil monolith or two-dimensional vertical sketch of a soil, identify the following:
soil profile, soil solum, A horizon, B horizon, C horizon, R horizon, parent material,
regolith, soil pedon, surface soil, and subsoil.
Definitions below.
Soil horizon
Layers in the soil which are parallel to the soil surface. The physical characterstics are different
between each layer. The result of the weathering of materials due to the soil forming factors.
Soil profile
2D cross sectional view of the soil, a vertical section of soil through all its horizons and
extending to parent materials below, from the ground surface to the parent rock
Soil solum
The 3D soil body in which the effects of climate and biological activity are most pronounced. A,
E, and B horizons compose the soil solum and are impacted by water (climate) and biota. Being
changed because of active factors.
Soil pedon
3D soil unit with all character of soil (1 m square, 2 m depth). Smallest soil individual.
A horizon
