SWS3022 Exam 1 review

Flashcard maker : Isabella Parker
the dimensions of the earth.
Diameter: ~8000mi, Circumference: 25000mi, SA:200million mi^2, Earths crust: 35mi
2. Understand that definitions of soil depend strongly on the concerns of those making the definitions. so who?
Agriculture, ecology/life, geology, environment, public health
the parameters related to soil composition for an idealized surface soil.
45% mineral, 5% organic, 50% pore space
basic functions of soils in the environment.
regulator of water supplies. medium for plant growth. habitat for biota. public health. storage of raw materials
4 basic processes involved in soil formation
Transformations, Translocations, Additions, losses
Transformations
Chemical or physical modifications of elements in soil.

Weathering of Rocks and Minerals – Critical to Soil Formation
Change in Size and Arrangement of Mineral Particles
Decomposition/Alteration of Primary Minerals
Synthesis of Reactive Secondary Minerals – Silicate clays, Fe/Al Oxides
Elemental Transformation (e.g. Fe3+ Fe2+)
Organic transformations: synthesis of Organic Acids, Humic materials, soluble
organic compounds

Additions
Input of organic matter from leaves, roots, organisms
Input of dust particles on the soil surface, water-deposited solids
Manure or fertilizer application
Losses
Erosion of soil materials
Decomposition of organic matter
Movement of salts, clays, O.M.
Translocations
loss of: Fe/Al oxides, Organic Matter, Iron and clay from water
the basics of weathering.
Critical to Soil Formation, Physical and Chemical Alteration and Reorganization of Rocks and Minerals.

Critical in the Creation of the Parent Material and
Alteration of Parent Material to Secondary Components

What are the 2 types of weathering?
Physical weathering; Chemical weathering
The breakdown of materials into smaller parts that allows them to be more chemically reactive is ______ weathering
physical
By ______ weathering, we alter/reorganize precursor minerals into secondary minerals.
Chemical

*most precursor minerals are aluminum + silicon

In the presence of oxygen, Fe2+
converts to Fe3+ which forms
relatively insoluble oxides of iron,
producing a “rusty” coloring. This
is an example of a ____________
transformation
Which are more reactive, precursor minerals or secondary minerals?
Secondary minerals are the seat of the chemical reactivity
Weathering of primary minerals
releases Fe2+ which is soluble
in water is also subject to
________ downward.
translocation
the 5 soil forming FACTORS and what they mean or imply.
Parent Material – original material

Climate – temperature, moisture

Organisms/biota – vegetation, macro, micro

Relief (Topography) – altitude, slope

Time – controls extent of other factors

What type of parent material dominates Florida’s soils?
Florida’s P.M. are derived from:
Sandy+ Clayey Marine & Alluvial Sediments
deposited over BEDROCK

alluvial = from streams & rivers
marine = from oceans

5 Sources of Parent Materials: (explain each)

1) Residual
2) Alluvial
3) Marine
4) Eolian
5) Glacial

1) Residual = formed in place from ROCKS & MINERALS
2) Alluvial = deposited by RIVERS & STREAMS
3) Marine = deposited by OCEANS
4) Eolian = deposited by WIND
5) Glacial = deposited by ICE
origin of the sediments that ultimately formed the parent materials for Florida’s soils.
Parent Materials Resulted from Influx of Continental Sediments
(Marine & Alluvial)
parent material
Original Material
Climate
Temperature, Moisture
Organisms/biota
Vegetation, Macro, Micro
Relief (Topography)
Altitude, Slope
Time
Controls extent of other factors
How does temperature and rainfall impact soil formation?
it ACCELERATES soil formation:

Heat increases rates of physicochemical processes

Water increases weathering rates and translocations

Why do soils in Florida tend to be more highly developed than soils in the S.W. United States?
It is due to climate: High temperatures and rainfall accelerate soil formation

Heat increases rates of physicochemical processes;
Water increases weathering rates and translocations

What is pedogensis?
The process of soil formation as the result of the
combination of soil forming FACTORS and PROCESSES
What are soil horizons?
Roughly parallel layers in the soil
with varying composition and properties
6 master horizons discussed and be able to identify/recognize features of each.
O A E B C R

the
Octopus
Ate
Emily
Because the
Crabs
Ran (free)

O horizon
ORGANIC
Organic horizon formed above the mineral soil.
Derived from decomposition of plant and animal residues
At least 20% organic
Range in thickness from absent to meters thick.
A Horizon
ABOVE
Topmost mineral horizon (topsoil)
Subject to significant weathering
Accumulates organic material
Often darker than soil below.
High in plant roots, biotic activity
Zone of gas and water exchange
E Horizon
EXIT
Zone of Eluviation, E = Elluviation = exit,
Maximum Losses by Translocation:
(Organic matter, Clays, Carbonates, Fe, Al oxides) Generally LIGHT colored (contains resistant primary minerals)
B Horizon
BUILD UP ZONE (accumulation zone)

Accumulates material lost from above, or forms in place.
(translocation, transformation)

Usually a Zone of Illuviation (additions, translocation).
Clay, O.M., Fe/Al, salts
Soil structure
Potential color development
Potentially HIGH reactivity
(concentration of secondary minerals/O.M.)

C Horizon
COPY CAT zone – (copies parent material)

Closely resembles parent material
Unconsolidated
Little or no evidence of Alteration or development

R Horizon
RESTING in bed zone

bedrock

Subordinate Distinctions of the O horizon:

Explain Oa, Oe, Oi:

Oa-HIGHLY decomposed organic material (sapric)

Oe-Moderately decomposed organic material (hemic)

Oi-Slightly decomposed organic material (fibric)

A horizon subordinate distinctions:
p = disturbed, plowed
Subordinate Distinctions
of the B Master Horizon:

Explain: Bt, Bh, Bw, Bg

Bt=accumulation of silicate clays
Bh=illuvial accumulation of organic matter
Bw=”Weak” development of color or structure
Bg=Gleying – wet, low oxygen
Accumulation of silicate clays is what B subordinate horizon?
Bt
Illuvial accumulation of organic matter is what B subordinate horizon?
Bh (dark colored bc lots of O.M. and many Bh horizons are called spodic horizons)
What is the basic relationship between time and the extent or degree of soil development?
Longer time => greater development
What is Vertical horizon subdivisions vs Transitional horizons?
Vertical: Characterized by similar master and/or subordinate properties separated by “degree”.
(ex. Bt1, Bt2, Bt3 increasing clay content —>)

Transitional Horizons: layers BETWEEN master horizons-in between subordinate and dominant
(ex: A—> AE—> and then E)
(the first letter listed is the dominant character)

What color would we expect soil to be with:

a) Organic matter

b) Iron oxides

c) Removal of materials

a) Grey to Black- Organic Matter

b) Orange to Red- Iron oxides

c) Light Colors- Removal of materials

What are the 3 components to soil color?
HVC: Hue, value, chroma
What soil color component is the dominant spectral color; related to the wavelength
of light?
Hue

(Related to the
proportions of red to yellow. so 10YR has both yellow and red)

What soil color component is related to total
amount of light reflected? (aka how light/dark the color is)
Value
What is the measure of the strength
of spectral color?
Chroma
10YR 6/3
Hue: 10 YR
Value: 6
Chroma: 3
When it comes to value ( going up/down the chart), what value would you expect a LIGHT soil color to have?
High value = light color

Low value = dark color

What are the 3 particle size separates?
Sand
Silt
Clay
Which particles size separate has a size range of:
(2.0 – 0.05)
(0.05 – 0.002)
(<0.002)
Sand (2.0 – 0.05)
Silt (0.05 – 0.002)
Clay (<0.002)
What are the dominant minerals in:

(a) Sand
(b) Silt
(c) Clay

(a) Sand = Quartz
(b) Silt = Quartz/Feldspar
(c) Clay = Secondary minerals
(T/F)
Sand and silt fractions are dominated by secondary minerals
The clay fraction is dominated by reactive primary minerals
FALSE:
Sand and silt fractions are dominated by primary minerals
The clay fraction is dominated by reactive secondary minerals
____ _______ refers to the relative
amounts of three distinct particle
size separates comprising the
mineral component of soils.
soil texture
What indicates the maximum volume
of water and gases a soil can hold?
Total porosity
How does texture generally affect overall porosity?
All else being equal, finer-textured soils have
GREATER overall porosity than coarse-textured soils.

(this is due to greater surface area in fine soils!!)

How does texture generally affects pore size distribution?
Large Particles Yield Large Pores

Fine particles yield small pores

How does texture affect water and gas movement in Coarse- textured soils?
Large Pore Spaces
Rapid Water Movement
Poor Water Retention
Gas Exchange Facilitated
How does texture affect water and gas movement in fine- textured soils?
Pores are small and convoluted
Clay-Air and Water Movement is Very Slow
Water Retention is High (holds H20 well!!)
Be able to use the soil textural triangle:

(a) 70% Sand, 20% Silt, 10% clay would be what kind of soil?

(b) 25% sand, 45% silt, 30% clay

(a) Sandy Loam
(b) Clay Loam
How many textural classes are there?
Depending on the relative proportions of these
three particle size fractions, soils are assigned
12 different soil textural classes.
What is relationship between soil texture and specific surface area; why is it important?
Water Movement and
Potential Reactivity
What does Stokes’ Law indicate and how can it is used in the hydrometer method to assess soil texture?
Stokes’ Law allows determination of the
time required for different particle size
separates to settle from a suspension.

Determination of the amount of
materials settled –> yields texture
1 minute = Sand settles out
6 hours = Silt settles out

What is the equation for Stoke’s Law:
V = K D^2

K (constant)= 11,241 cm-1,sec-1
D= Diameter of particle size

Sand with a diameter (D) =1 mm will settle how fast ?
D= 1 mm -> convert to cm D= 0.1 cm
V= (11,241)* (.1)^2 = 112.4 cm/sec
Explain the hydrometer method and how to calculate % sand, silt, and clay given appropriate measurements.
As particles settle out, the suspension becomes less dense.
The hydrometer measures the density of the suspension.
The units are g/L.
In dense suspensions, the hydrometer floats higher in less dense suspensions it sinks.
is calibrated to read zero in pure water at 20 degrees.
hydrometer method
Add __ g soil to 1 liter of water
1 min, difference in g is sand settled. 6hrs is clay. put each __g over full __g amount *100%= measurements
If you add 40g of soil to 1 L of water and at t= 1 min density = 10g/L. What is the percent of sand?
Sand settled= 40g- 10g = 30 g
Sand % = 30g sand/ 40 g soil x 100= 75%
Using the initial 40g of soil added to 1 L of water: At t= 6 hours density = 4 g/L; what percent is silt? clay?
Clay content = 4 g/L

% Clay: 4g/ 40 g X100 = 10%
%Silt: 100 – (75+10)= 15%

What numerical value for soil particle density.
2.65 g/cm3
T/F: For finer-textured soils there is a lower specific surface area thus decreasing reactivity
False:
Fine-textured soils = greater Specific surface area therefore are exposed to more and are reactive!
How is soil bulk density computed? and what it is.
BD = (mass O.D. soil)/ (volume solids + pores)

Density of soil INCLUDING the
particles and the pore spaces.

Based on the Number of Particles Packed into a Given Volume
B.D. ranges between 1.0 and 1.6 g/cm3
(for mineral soil with 1 – 5% organic matter)

How texture, organic matter, aggregation, compaction, and depth in profile affect porosity
and bulk density.
Organic matter increases porosity, decreases BD
Aggregation increases porosity, decreases BD
Depth in profile decreases porosity, increases BD
Compaction decreases porosity, increases BD
Factors which increase porosity, ______ density
decrease
Know the range in bulk densities for a typical mineral soil containing approximately 1-5% organic matter.
BD of typical mineral soils = 1.0 – 1.6g/cm^3
If BD is high then porosity is ?
If BD is low then porosity is?
Bulk density high – porosity low
Bulk density low – porosity high

Factors which increase porosity, decrease density.

What indicates the SIZE / diameter of pores?
Pore size distribution-

Macro, Meso and Micropores.
macropores > 0.08 mm in diameter
large, freely draining
sands, inter-aggregate pores
large enough to accommodate roots

Mesopores Moderate Size 0.08 – 0.03 mm
Retain water well against drainage
Accommodate fungi and root hairs

Micropores < 0.03 mm in diameter small, storage of water Accommodate Bacteria clays, intra-aggregate pores

What indicates the fraction of a total soil volume that is pore space/ indicates the maximum volume
of water and gases a soil can hold?
Total Porosity
What is the reactivity for:

Fine-Textured Soils
Compacted/Uncompacted Soils
High / Low Density Soils
High Organic Matter Soils

Fine/compacted/high density = Small pores slow water and gas movement, but increase contact between soil solution and soil particles, INCREASING reactivity (think: this is why clay is so reactive.. bc very fine textured!)
(T/F): High organic matter content decreases bulk density
True: High organic matter increases porosity, decreases BD
What soil structure is and how it affects soil porosity and pore size distribution?
it affects:
the movement of water into and through soil;
the degree of aeration;
the ability of crop roots to grow through the soil profile; and
the ability of the soil to resist soil erosion.

Large pores drain freely, small pores store water effectively
Poor soil structure can
inhibit infiltration of
water, water movement,
growth of roots.

what type, class, and grade indicate relative to soil structure. Know the structural types
types( shapes):
Granular,Platy,Block-like, Prism-like
class(size), grade (strength)
How texture, density, and structure impact water and gas movement and potential reactivity:

Fine textured: would react with gas/ H20 slower and therefore be more reactive

Course textured- would react with gas/H20 quickly; lower reactivity

High density: the higher the density the slower the H20/gas movement

There is _____ movement between aggregates and ____ movement around aggregates?

Spheriodal soils have a granular structure. The aggregates are 1- 10 mm (1/25- 2/5 in.) in diameter with rounded corners. This structure is usually seen in the A horizon or the upper layer of fine or medium-textured soils. Granular structure in the seed or transplant zone is important for good contact and early establishment.
Blocky soil aggregates are often larger in size (5- 50 mm or 1/5- 2 in. in diameter) and form irregular-shaped or cube-like blocks. This structure promotes good drainage, aeration and root penetration. Usually these structures are found in the B horizon or just below the colour change in many soils. Blocky structures greater than 50 mm (2 in.) in diameter are often an indication of compaction or soil management problems.
Platy soils form thin layers or horizontal planes. This type of structure can be found in both surface and subsurface soil horizons. It is commonly seen in undisturbed or no-till soils. Platy structures in sandy soils often indicate compaction problems.
Fine textured: would react with gas/ H20 _______ and therefore be more reactive
Course textured- would react with gas/H20 quickly; ______ reactivity
High density: the higher the density the _______ the H20/gas movement
There is _____ movement between aggregates and ____ movement around aggregates?
(a) – slower
(b) – decrease
(c) – slower
(d) slow movement between aggregates but fast movement AROUND aggregates
Small pores = Intra-aggregate pores ( within )
Large pores= Inter-aggregate pores ( between)
T/F: Large pores drain freely, small pores store water effectively
TRUE
What is the boiling and freezing point of water?
The freezing point of water, of course, is 0 degrees Celsius and the

Boiling point is 100 degrees Celsius, giving us a liquid range of 100 degrees.

How hydrogen and oxygen are bonded within a single water molecule? Know the name of
the bond.
The bonding of hydrogen and oxygen in a water molecule is covalent.

The hydrogen atoms share their single electron with oxygen thereby completing its valence shell, while oxygen, in turn, shares one of its lone electrons with each hydrogen completing their valence shells.

How is water made polar?
Oxygen is highly electronegative, in a chemical bond, electrons tend to be drawn toward oxygen, and away from other atoms to which it is bonded.

The electrons tend to cluster near the oxygen
The overall electrical charge on the molecule is zero, There is a slight partial negative
charge near the oxygen atom, and
a slight partial positive charge near
the hydrogen atoms in the molecule

Polarity and how it impacts bonding between water molecules in the liquid and solid.
So, in liquid as well as solid water or ice, water molecules are linked together electrostatically which imparts unusual stability and strength. This accounts, for example, for water’s unusually HIGH boiling point compared to other liquids.

H20 is a polar molecule, the bonds between O and H are shared mutually but NOT equally. So any H2O molecules near by will orient themselves to H-bond with each other.

(Tends to keep water in the liquid phase at higher temperatures than compositionally similar liquids like hydrogen sulfide. So, evaporation requires far less energy resulting in a much lower boiling point.)

What is the name of the bond that exists between water molecules in the liquid and solid state?
Hydrogen bond.

(An electrostatic bond is established between the water molecules; transitory, but extensive, occurring between each water molecule and an average of between 3 and 4 neighboring molecules at any given time.)

Which is more dense: solid water or liquid water?
Solid water = less dense (less molecules in ice)
Liquid water = more dense (more molecules)

As water cools, it becomes more dense until it reaches a temp of about 4 degrees C.
Hydrogen bonding gives water great stability!!
And results in a number of unusual properties
Cohesion – attraction between water molecules

What is the definition of heat capacity?
And the value for water?? (Note the units)
heat capacity = The amount of heat input required to raise the temperature of 1 g of a substance by 1oC.
(cal/g· C)

1.0 for water

What is heat of vaporization?
It is the amount of heat input required to VAPORIZE water (turn from liquid to a gas)

Water = HIGH heat of vaporization.

Why does water have such a HIGH heat capacity relative to other common liquids like alcohol?
Because of extensive H-bonding in water!

When heat is added to water, the molecules speed up or vibrate more freely. This disturbs hydrogen bonds, but causes only a small change in temperature, because much of the heat energy is used to break or disrupt the hydrogen bonds

heat capacity = 1.0 for water

Why is water SLOW to evaporate compared to other common liquids?
Because of H-bonding !! for H20 to evaporate, all the strong H-bonds must broken so it takes awhile.

Also has a HIGH heat of vaporization -> meaning that will take a lot of energy input to turn it to a gas.

How heat capacity impacts body temperature.
Extensive Hydrogen Bonding Allows Water
to exist as a Liquid at Normal Temperatures
And across a wide range in temperatures

(your body ca

How heat capacity impacts soil temperature.
It is very difficult to evaporate water (alot of energy required), which is good because it keeps soils moist.

Soil temperature largely
is controlled by moisture
(soil water content)
Heat energy is required to break hydrogen bonds between water molecules, and heat is released when hydrogen bonds are formed.

Why is water relatively SLOW to evaporate?
The addition of heat to water causes a relatively small change in the temperature of the water, because much of the heat energy is used to disrupt the hydrogen bonds.
How can we calculate water content on a WEIGHT basis?
Weight=( Moist-Dry weight) /(dry soil weight) X 100%
You collect a 200 cm3 soil sample. Its moist weight is
150 g. After drying, the dry weight is 100 g.
What is the gravimetric water content?
Grav. water content = (150g- 100g) / (100g) x 100% = 50%
How can we calculate water content on a VOLUME basis?
Volume= Vwater/Vsoil x 100% (1cm^3=1 g)
You collect a 200 cm3 soil sample. Its moist weight is
150 g. After drying, the dry weight is 100 g.
What is the volumetric water content?
Vol. water content = volume water/ volume soil x100% =
50 cm3 / 200cm3 = 25%
(T/F): The soil water content depends on the amount of pore space filled.
True
At saturation the volumetric water content = ?
total porosity

So if soils are completely saturated with a volumetric water content of 75%, what is the total porosity?

Tp = 75% also!!!

Vol. water content = Total porosity @ saturation !!!!

What are the 2 forces that are responsible for water movement in soils?
Gravity

Capillarity

What 2 forces make up Capillarity?

(spontaneous movement of water into /thru pore spaces in soil without the aid of gravity)

Adhesion: attraction of water molecules to a surface
(they ADHERE to a surface)

Cohesion: attraction of water molecules to each other
(they all “hold hands”)

How do adhesion and cohesion work together to create capillarity in soils?
There is Adhesion to the tube or pore wall
and there is Cohesion between water molecules
T/F: Capillarity (and gravity) move water in saturated soils
FALSE: Capillary and gravity move water in UNSATURATED soils (bc saturated soils can’t hold any more water)
If a pore radius decreases, how will this impact capillary forces?
pore radius decrease, capillarity increase

If pores shrink; capillarity forces become stronger

1) Describe the capillary forces in a loose, sandy soil:

2 ) what dominates: capillary forces or gravity?

3) Where will water move?

Loose sand = large pores spaces

Capillary forces will be weak,

gravity dominates

Water will move mostly downward

1) Describe the capillarity forces in a compacted clayey soil:

2) what dominates: capillarity forces or gravity?

3) Where will water move?

1) compacted clay = small pore radius = strong capillary forces

2) capillarity forces dominate

3) Water will move multi-directionally

What are the capillarity strength’s for: Particle/pore size = Large, medium, small
Large particle/pore = weak capillarity
Medium = moderate capillarity
Small = strong capillarity
Macropores would have ______ capillarity forces
weak
(not much water being sucked through large area)
T/F: Any factor that shrinks pore diameter, tends
to increase the strength of capillary forces
which will increase the overall influence of
Capillary forces relative to Gravity
TRUE
how porosity differences due to structure would exert different capillary forces on water.
Macropores = weak capillarity / Micropores = strong capillarity
At saturation, all the water movement will be by ________
At saturation, all the pores are filled
and capillary forces are satisfied.

All water movement will be by GRAVITY

As water content in a soil decreases,_____ pores
empty first and the size of the pores
still holding water also decreases
large
As water content in a soil decreases, what happens to the capillary forces?
Thus, capillary forces become STRONGER
and begin to control water movement
Gravity dominates flow at ____ water contents
Capillarity dominates flow at _____ water contents
high

low

Energy waiting to be used or exploited
potential energy
The greater the height, the _______ the gravitational potential energy.
GREATER

Gravitational potential energy is
due only to the height of an object
(water) above a reference point.
The higher the elevation the greater
the energy.

What are the units of gravitational potential energy?
Units are Cm of height above
a chosen reference level.
The choice of a reference point for gravitational potential is arbitrary. T/F
True

(Know that the choice of a reference point for determining gravitational potential up to you.)

Is gravitational potential energy independent or dependent on soil properties?
gravitational potential energy is NOT impacted by soil properties; just by height from the reference level.

so it is independent of soil properties

Capillary potential energy applies to what types of soils?
(sat / unsat
Matric/Suction Potential Energy

Applies to unsaturated soils

In a saturated soil, this quantity would be zero, since all the pores are filled. Therefore, quantification of matric potential energy will apply to unsaturated soils.

In saturated soils the capillary potential energy would be :
What “Relates to the ability or potential of soils to move water into pores without gravity” ?
Capillary Potential Energy
The matric/capillary
potential energy of
an unsaturated soil
is always _______
NEGATIVE

more negative = stronger capillary forces

Which would have the stronger, more negative, capillary forces: Clay or sand?
Clay = small pores = STRONG capillary forces
(would have a highly negative potential)

Sand = large pores = WEAK capillary forces

Is Pressure potential energy positive or negative when strong?
Positive

In soils, submergence potential is measured based on the depth below a water table. The soil in this case is saturated and will exert a pressure downward, forcing water through the pore spaces below resulting in flow. In this case the pressure is positive rather than negative as is the case for matric potential which is operating in the capillary fringe, drawing water above the water table.

Equal to the distance below a free water surface =
Pressure potential
Which would have the stronger, more negative, capillary forces: Dry or moist soil?
Dry = Stronger (the urge to suck any available water is high)

Moist = weaker

T/F: Pressure potential only occurs under saturated conditions.
True
Calculate TOTAL potential energy at a given point in a soil given the appropriate parameters.
Total Potential Energy=Ψg +Ψm + Ψp
What is plant available water?
Plant Available Water = Field Capacity – Permanent Wilting Point

(Water left in previously saturated soil after its been drained by gravity) – (water that plants can’t access)

Know how to determine if water will flow between two points in a soil and the direction of flow.
Water will always flow from areas of
high total potential to low total potential.
to do this:

Sum the individual potentials at each point
Determine if there is a difference in potential between points

How can we calculate gradient?
(The driving force for water flow)
Gradient = (TpA- TpB ) / (dist. b/t A & B)
Know that the greater the gradient, the _______ the driving force for water movement.
stronger
T/F: Water moves in response to capillary potential energy only.
FALSE:

Water moves in response to differences in TOTAL potential, not just one potential

The ease with which water moves through soils is:
Hydraulic conductivity
(a) Texture – small particles = small pores = ______ conductivity

(b) Density – high density suggests _____ porosity and small pores

(c) Structure – inter-aggregate macropores ______ conductivity
(Between Aggregates)

(a) poor

(b) low

(c) improve

How do we combine hydraulic conductivity and the gradient to determine overall Flow of water in soils?

Note the units of flow.

Hydraulic conductivity
is determined by measuring
the volume of flow through
a cross sectional area of
soil per unit time

Darcy’s Equation: Q = K * gradient
in cm/hr

10YR 5/10
hvc, color in middle of hue yellow-red, 5 medium value(lightness), chroma of 10
gravitational potential energy
independent of soil properties
due only to the height of an object
(water) above a reference point.
The higher the elevation the greater
the energy.
Units are centimeters of height above
a chosen reference level.
Capillary Potential Energy
Applies to unsaturated soils
Relates to the ability or potential of soils to move water into pores
matric and Suction Potential
capillary pot energy in saturated soils
. In a saturated soil, this quantity would be zero, since all the pores are filled
Soil Texture and Matric Potential
Fine-textured soils generally exert stronger capillary forces than do coarse-textured soils because pore sizes are smaller.
total potential engergy
Total Potential is the Sum of the Gravitational,
Matric, and Pressure Potentials
Water moves in response to differences
in total potential energy between two points
units of potnetial
cm of water
What are the 7 existing orders in Florida?
Entisols
Ultisols
Inceptisols
Alfisols
Mollisols
Spodosols
T/F Ultisols are “young soils” weakly developed sandy or clayey
FALSE: Entisols = young soils/ weakly developed!!
T/F Bt soil means that there is an accumulation of silica clay
TRUE
Bt soil is REQUIRED for Alfisols and _____
Ultisols
Which is associated with ACIDIC vegetation and is formed under wet conditions? Also it is often very poorly drained and contains Pine Flatwoods?
Spodosols
T/F Spodosols are the #1 soil in state of FL
TRUE

State soil: Myakka Fine Sand

“p” applies to which horizon?
A

p – plowed / disturbed

(T/F) Stokes’ Law determines the density of a soil suspension.
False – hydrometer measures the density of a suspension
(T/F) Water has exceptionally high electronegativity.
True
(T/F) Water’s POLARITY is directly responsible for many of its unusual properties.
True
(T/F) The strength of capillary forces is inversely related to the radius of the pore space.
True
(T/F) The high heat capacity of water makes it a good coolent to use in condensers to keep from over heating.
True- because water can absorb alot of heat and not increase temperature that much

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