SOIL SCIENCE EXAM PRACTICE
QUESTIONS AND 100% CORRECT
ANSWERS!!
Volume Composition of surface loam soil when conditions are ideal for plant growth
Properties of sand, silt, and clay
These three properties are used to identify the soil texture.
Sand: Can be seen with the naked eye. It is loose and gritty when wet of dry.
Silt: Can be seen with a microscope. It is smooth when wet and powdery with clods when wet.
Clay: Can be seen with an electron microscope. It is sticky, malleable when wet and hard clots
when dry.
Understand the differences between the 3 different types of rocks
Igneous Rock: Rock formed from the coolness and solidification of magma that has not been
changed appreciably since its formation. Example: Quartz or granite
Sedimentary Rock: A rock formed from materials deposited from suspension of precipitated
from solution and usually being more or less consolidated. The principal sedimentary rocks are
sandstones, shales, limestones, and conglomerates.
Metamorphic Rock: A rock that has been greatly altered from its previous condition through the
combined action of heat and pressure. For example, marble is a metamorphic rock produced
from limestone, gneiss is produced from granite and slate is produced from shale.
Understand the statement "Weathering combines the processes of destruction and
synthesis"
Weathering is a biochemical process that involves both destruction and synthesis. The original
rocks and minerals are destroyed by both physical disintegration and chemical decomposition.
Without appreciably affecting their composition, physical disintegration breaks down rock into
smaller rocks and eventually into sand and silt particles that are commonly made up of individual
minerals. Simultaneously, the minerals decompose chemically, releasing soluble materials and
, synthesizing new minerals, some of which are resistant end products. New minerals form either
by minor chemical alterations or by complete chemical breakdown of the original mineral and
resynthesis of new minerals.
How is water involved in chemical weathering reactions?
Hydration: Intact water molecules may bind to a mineral by a process called hydration. For
instance if you combine Hermatite with water you get Ferrihydrite.
Hydrolisis: In hydrolysis reactions, water molecules split into their hydrogen and hydroxyl
components and the hydrogen often replaces a cation from the mineral structure. For example:
The potassium released is soluble and is subject to adsorption by soil colloids, uptake by plants,
and removal in the drainage water.
Dissolution: Water is capable of dissolving many minerals by hydrating the cations and anions
until they become dissociated from each other and surrounded by water molecules. Gypsum
dissolved in water provides an example.
Acid Reactions: Weathering is accelerated by the presence of acids, which increase the activity
of hydrogen ions in water. For example, when carbon dioxide dissolves in water the carbonic
acid produced hastens the chemical dissolution of calcite in limestone or marble.
Oxidation-Reduction: Minerals that contain iron, manganese, or sulfur are especially susceptible
to oxidation - reduction reactions. When rocks containing such minerals are exposed to air and
water during soil formation, the iron is easily oxidized and becomes trivalent Fe(III) (ferric).
Complexation: Soils biological processes produce organic acids such as oxalic, citric, and tartaric
acids. The acids mix with water to disintegrate the
What are the 5 factors of soil formation and how they affect soil formation?
Five factors that affect soil formation are: CLORPT
Cl - Climate - precipitation and temperature
QUESTIONS AND 100% CORRECT
ANSWERS!!
Volume Composition of surface loam soil when conditions are ideal for plant growth
Properties of sand, silt, and clay
These three properties are used to identify the soil texture.
Sand: Can be seen with the naked eye. It is loose and gritty when wet of dry.
Silt: Can be seen with a microscope. It is smooth when wet and powdery with clods when wet.
Clay: Can be seen with an electron microscope. It is sticky, malleable when wet and hard clots
when dry.
Understand the differences between the 3 different types of rocks
Igneous Rock: Rock formed from the coolness and solidification of magma that has not been
changed appreciably since its formation. Example: Quartz or granite
Sedimentary Rock: A rock formed from materials deposited from suspension of precipitated
from solution and usually being more or less consolidated. The principal sedimentary rocks are
sandstones, shales, limestones, and conglomerates.
Metamorphic Rock: A rock that has been greatly altered from its previous condition through the
combined action of heat and pressure. For example, marble is a metamorphic rock produced
from limestone, gneiss is produced from granite and slate is produced from shale.
Understand the statement "Weathering combines the processes of destruction and
synthesis"
Weathering is a biochemical process that involves both destruction and synthesis. The original
rocks and minerals are destroyed by both physical disintegration and chemical decomposition.
Without appreciably affecting their composition, physical disintegration breaks down rock into
smaller rocks and eventually into sand and silt particles that are commonly made up of individual
minerals. Simultaneously, the minerals decompose chemically, releasing soluble materials and
, synthesizing new minerals, some of which are resistant end products. New minerals form either
by minor chemical alterations or by complete chemical breakdown of the original mineral and
resynthesis of new minerals.
How is water involved in chemical weathering reactions?
Hydration: Intact water molecules may bind to a mineral by a process called hydration. For
instance if you combine Hermatite with water you get Ferrihydrite.
Hydrolisis: In hydrolysis reactions, water molecules split into their hydrogen and hydroxyl
components and the hydrogen often replaces a cation from the mineral structure. For example:
The potassium released is soluble and is subject to adsorption by soil colloids, uptake by plants,
and removal in the drainage water.
Dissolution: Water is capable of dissolving many minerals by hydrating the cations and anions
until they become dissociated from each other and surrounded by water molecules. Gypsum
dissolved in water provides an example.
Acid Reactions: Weathering is accelerated by the presence of acids, which increase the activity
of hydrogen ions in water. For example, when carbon dioxide dissolves in water the carbonic
acid produced hastens the chemical dissolution of calcite in limestone or marble.
Oxidation-Reduction: Minerals that contain iron, manganese, or sulfur are especially susceptible
to oxidation - reduction reactions. When rocks containing such minerals are exposed to air and
water during soil formation, the iron is easily oxidized and becomes trivalent Fe(III) (ferric).
Complexation: Soils biological processes produce organic acids such as oxalic, citric, and tartaric
acids. The acids mix with water to disintegrate the
What are the 5 factors of soil formation and how they affect soil formation?
Five factors that affect soil formation are: CLORPT
Cl - Climate - precipitation and temperature
