Soils Exam 1

entisol

"baby soil" , not enough time has passed to form horizons which soil order is this

inceptisol

"toddler soil" grade about entisol, starting to see horizons, high base saturation which soil order is this

A

"top soil" is generally equivalent to which soil horizon which: B, E, C, A, D

base saturation

% of soil exchange sites occupied by bases ex: K, Mg, Ca, Na

field capacity

% of water remaining in the soil after the saturated (or satiated) soil has drained of gravitational water matric pot = (-)

redder

(Fe+3) iron (hematite) makes soil appear _____ - oxidized - dehydrated conditions

yellower

(Fe+3) iron +OH (geothite) make soil appear ____ - oxidized - hydrated conditions

parent material: Till what is the particle transport and degree of sorting

- Poorly sorted - coarse fragments randomly deposits as glacier moves

extrusive

- fine - faster cooling rate - small grain sizes

improving soil aeration

- improve peds (make more macropores with +Ca and OM) - Ca brings things together which makes more pores space - improve drainage - tillage (works in A horizon, below may be compacted)

parent material: Volcanic ash what is the particle transport and degree of sorting

- okay assortment - eruption - like glass - amorphous (no crystal structure)

general characteristics of soil to support plants

- support/ medium for growth - nutrients (recycling system for nutrients and organic waste) - water (supply) - habitat for organisms - modifier of the atmosphere

parent material: Eolian what is the particle transport and degree of sorting

- well sorted - No coarse - uniform small fragments

parent material: Alluvium what is the particle transport and degree of sorting

- well sorted - coarse fragments - high energy - small fragments - low energy

parent material: Glacial Outwash what is the particle transport and degree of sorting

- well sorted - coarse fragments - high energy - small fragments - low energy

parent material: Lacustrine what is the particle transport and degree of sorting

- well sorted - no coarse fragments

parent material: Colluvium what is the particle transport and degree of sorting

-poorly sorted -coarse fragments

clay particle

0.002 mm < plate like silicate clays, oxides (Fe, Al) has greater surface area more reactive more absorptive more plasticity

silt particle

0.05 - 0.002 mm spherical quartz, feldspars, micas

macroaggregate

0.25 - 5m

Db

1.33 Mg of solids and pore space would this classify as Db or Dp?

Dp

1.33 Mg solids (half), and half pore space would this classify as Db or Dp?

% air pores

100 - (Db/Dp *100) - (Pw *Db)

% pore space

100 - (Db/Dp x 100)

granite and basalt

2 examples of igneous rocks

sand particle

2-0.05mm spherical quartz and minor # of feldspars low plasticity low reactivity low absorptive capacity

microaggregate

2-250 nm (includes clay and OM)

soil monolith

2D - verticle section of the soil profile through all of its horizons and extending into the parent material. its extracted in the field and then mounted for displaying and teaching purposes

micropores

</= 0.08 mm ex: clay in soils

macropores

> 0.08 mm ex: granular structure

matric, gravity

A = clay B = sand what forces act in the A to move water: *water will build before moving into the next layer due to clays water holding abilities ** acts as a mechanical barrier to roots** what forces act in the B to move water:

gravity, matric

A = sand B = clay what forces act in the A to move water: what forces act in the B to move water:

soil solum

A and B horizon

greater porosity

A clay soil with strong fine granular structure is likely to have a ____ than a sandy soil which: greater porosity higher particle density lower porosity higher bulk density

angular blocky

A soil has A, B, C horizon. Structural types in the soil are granular, massive, and angular blocky. The structural type in the B horizon is likely to be ______ which: massive granular angular blocky no difference in probability among these structural types

41.3%

A soil has a Db of 1.55 gcm3 and a Dp of 2.64gcm3. what is the % pore space?

20%

A soil has a field mass of 27 grams and a dry mass of 22.5 grams. what is the Pw of this soil?

what are the 8 most abundant elements in the earths crust?

Al, Fe, Ca, Na, K, Mg, O, Si

glacial till

An unsorted, transported parent material would most likely be identified as _____ which: loess lacustrine glacial till alluvium glacial outwash

Mg, Ca, Na, K

Bases in the soil include: which: Fe, Mg, Ca, Na Mg, Ca, Na, Si Mg, Ca, Na, Al Mg, Ca, Na, K

of the 8 most abundant elements in the earths crust, which are bases -Al -Fe -Ca -Na -K -Mg -O -Si

Ca, Mg, K, Na

Na and K

Effects of Cations: ___ and ___ push away - soils dry into hard clods making it difficult to till - low water penetration - puddles when wet

Mg and Ca

Effects of Cations: ___ and ____ soils are generally friable - easy to till water penetrates easily no puddling when wet

gray, blue, green

Fe+2 (reduced iron) makes soil appear _____

of the 8 most abundant elements in the earths crust, which are hydrous oxides of aluminum or iron

Fe, Al, O

false

Flocculation is the process by which certain chemicals in the soil stabilize large soil aggregates true or false

true

For any soil, bulk density is always lower than particle density true or false

quartz pebble

For what substance would particle density be equal to the bulk density which: organic soil a well aggregated surface soil a quartz pebble a wet soil a soil clod

rocks formed when molten magma solidifies

Igneous rock can best be characterized as ____ which: -rocks formed when molten magma solidifies -rocks found primarily near volcanoes -rocks containing both feldspars and micas - rocks containing both a mixture of primary & secondary minerals - rocks formed from the recrystallization of sedimentary materials

5

In a load of 10 cubic meters of topsoils, approximately how many cubic meters of the volume would be solid material which: 5 2.5 1 7.5 Not enough evidence

true

In aeolian settings, silt sized particles can travel greater distances than sand sized particles true or false

eolian

Loess belongs to what parent material

material B

Material A contains 15% Al2O3 and 3% CaCO3 on an elemental basis and material B contains 25% Al2O3 and 0.2% CaCO3. ______ is most likely the soil material, if the other material is the rock which: material B material A

calcite dolomite and gypsum

Name 2 minerals that are comparatively soluble in soil solution, making them easily weathered

true

No tillage = low soil temps tillage = high soil temps mulch + tillage = moderate soil temps mulch = protects soil water - helps with weed control and preventing erosion - helps keep soil temps lower but not too low - in the summer the mulch is cooler than the air - helps keep temps perfect for crops -- too low = no seed germination -- too high = no moisture in soil for seeds

true

OM increases = water field capacity increases (Om has alot of surface area) Om increases = increase in holding of hygroscopic water

granular

Percolation of water through a soil profile is dependent on a number of factors that included soil peds. Of aggregates listed, which would have the highest percolation rate? massive granular subangular blocky plate like water moves through each of these at the same rate

% water by volume

Pw * Db

particle density (Dp)

SOIL SOLIDS mass per particle per volume weight of solids/volume of soil *assume 2.65 when not given

of the 8 most abundant elements in the earths crust, which are made of silicon

Si, O

soil pedon

The smallest unit or volume of soil that contains all the soil horizons of a particular soil type - 3D

Aridisol

This soil order can be found from San Antonio westward and generally has little to no horizonation hint: little rain occurs - dry which: Aquasol Entisol Aridisol

Vertisol

This soil order has high shrink swell capacity and can form large cracks when dry which: Mollisol Vertisol Ultisol

silt loam

USING SOIL TEXTURE TRIANGLE if a soil is 20% clay and 20% sand, what is the soil texture?

rocks have more bases that soil does in soils, bases get withered away easily (Al and Fe remain in old soils)

When given the elemental composition of rock and a soil formed from it, distinguish between the two

valence state

Which of the following is not considered one of the five major factors influencing soil formation which: Topography Native parent materials climate living organisms valance state

clay

____ has the largest capillary movement out of the soil textures

Hardness

____ is a frequently used property for helping to distinguish among mineral in hand specimens which: texture consistence hardness structure

Calcite (CaCO3)

____ is the principle mineral in limestone which: gypsum quartz calcite feldspar silicate clay

feldspar

____ weathers to form silicate clay minerals which: feldspar hematite apatite quartz geothite

O

_____ horizon is above mineral surface of the soil

hard

_____ is word to describe the consistence of a soil which: malleable slick mushy packed hard

Db

_____ predicts total porosity

soil temperature

______ is important because it affects the rates of physical, chemical, and biological processes - too high or low microbes and plants may be affected because it limits the release of nutrients (4 deg C is biological 0) - winter soil is warmer than atmosphere - summer soil is cooler than atmosphere - ____ to high = dry soils and increase rate of reactions

high Db

__________ low porosity and soil compaction

well aerated

a __________ soil have movement of gases sufficient to meet biotic requirements

soil

a dynamic natural body composed of mineral and organic solids, gases, liquids, and living organisms which can serve as a medium for plant growth

soil

a dynamic natural body having properties due to the combined influences of climate and biota as modified by topography acting on parent material over time

less

a grainy surface has ___ water

soil horizon

a layer of soil that is generally parallel to the soil surface. it is differentiated based on properties and characteristics of layers adjacent to it what is this

clod

a lump or clump of soil is often referred to as a

prismatic

a soil researcher has determined that a soils profile includes an A and B horizon. Of the structures listed, which would be found in the B horizon? which: plate-like prismatic spheroidal All of the above

clay

a sticky, putty-like feel indicates a high percentage of which soil separate? which: none sand humus silt clay

soil profile

a vertical section of the soil through all its horizons and extending into the parent material. 2D what is this

Soil profile

a vertical section through a soil showing its succession of horizons and the underlying parent material

what kind of parent material is found in the pan-handle of texas

aeolian

secondary particles

aggregates or peds

plant available water

amount of water released between field capacity and permanent wilting point ____ = field capacity - PWP

phosphates

apatite belongs to what mineral group

mollisol

areas of grassland, lots of organic matter, dark soils, high base saturation which soil order is this

aridisol

areas where there isn't a lot of rain (arid regions) - can have horizons what type soil order is this

clay

at a given potential ___ soils hold more water and at a given moisture content the water is held more strongly than other soils silt next then sand is the lowest

soil water energy

based on differences in the energy level from one site or condition to another - dictates where water goes and the rate of movement in plants and soils - water moves from wetter to drier soils water moves from higher to lower energy sites

matric potential

baseline is pure, free water = 0 water with low energy (neg potential) is tightly bound with little ability to move adhesion to surfaces makes it difficult for water to move = low energy state - measure in bars

complexation/ chelation

binding of cations by organic anions K2[Si6Al2]Al4O20(OH)4 + 6C2O4H2 + 8H2O <-> 2K +8OJ +6C2O4Al+ 6Si(OH)4 (solid) + acid <- complexation -> solution * K would break off and become a nutrient

weathering of rocks

biochemical process in which there is destruction and synthesis - physical - biochemical

how is glacial till deposited in the environment

by ice

how is colluvium deposited in the environment

by movement of materials from upslope due to GRAVITY (sometimes water)

how is glacial outwash deposited in the environment

by water

how is alluvium deposited in the environment

by water - STREAMS and rivers

how is eolian deposited in the environment

by wind

true

carbonates like, calcite and dolomite are some what soluble true or false

true

clays hold more water but it is harder to get ahold of in sands, hold less water but its somewhat easier to get ahold of

active soil formation factors

climate and biota (animal and plant life)

intrusive

coarse grains - slow cooling rate - large grain sizes

What kind of parent material will you find in East Texas, along the coast

coastal plain sedimentation

subsoil

compact soil below the surface soil, generally poor in nutrients and OM, less fertile that surface soils, particularly weathered

has no effect on

compaction of soils ______ particle density and increase in bulk density which: has no effect on decreases increases

igneous rock

cooling of magma

value

dark to light (soil) 2(dark) to 8(light) *influenced by OM more OM = darker

sedimentary rock

deposition of sediments and evaporation of water and then consolidation

residual parent material

develops in place from weathering of underlying rock

biochemical weathering of rocks

dissolution/decomposition of minerals results in synthesis of secondary minerals

A horizon

dominated by mineral particles but have been darkened by the accumulation of organic matter - top soil - less compacted - more sand and silt - smaller aggregates

percolation

downward movement of water through the soil profile - different based on pore sizes

osmotic potential

due to solutes in soil solution solutes = solids water around a solute has little freedom to move = lower energy potential *** only works if there is permeable barriers that bars the movement of solutes

chroma

dull to bright soil 0 (dull) to 8 (bright)

soil

dynamic natural body having properties due to the combined influences of climate and biota as modified by topography acting on parent material over time

soil consistence

ease which a soil can be reshaped or ruptured - depends on mositure -- dry, moist, wet ( plasticity, stickiness)

permeability

ease which gases, liquids, or plant roots penetrate or pass through the bulk mass of soil or layer of soil "how easily it can be moved through the soil"

parent material

effects on _______ _________ on soil properties are modified by the combination of influences of climate, biotic activities, topography, and time

flocculation

effects soil aggregates coming together - freeze/ thaw - physical activity - wetting / drying - roots/ animals - decaying OM / microbes - absorbed cations - tillage

stabilization

effects soil aggregates coming together as a group & cemented together - Organic glues (fungi) - Fe- Oxides - organic carbon - clay

TDR (Time-Domain Reflectometer)

electronic device gives indication of %water based on electric current - showing the flow of liquid helps determine matric potential

infiltration

entry of water into soil - only A horizon

low

fine textured soil = ______ Db than sand ex: clay and silt

Factors that influence soil aggregates:

flocculation and stabilization

metamorphic rock

from pre existing rock and high temp and pressure

hue

general spectral color of soil ex: 10Y 5YR

what happens to liquid movement when it encounters small pores that are dry ex: (top) sand loam/ clay (bottom)

gravity plays a role until it reaches the clay then capillary forces take over

Gravitational potential

gravity pulls water towards the center of the earth - higher in the profile = higher energy than lower in the profile gravity x height

aggregates or peds

group of soil particles that bind to eachother more strongly than other particles near

sulfates

gypsum belongs to what mineral group - relatively soluble

halides

halite and sylvite belong to what mineral group - very soluble

alfisol

horizons starting to form, located in areas with more rain, high-medium base saturation ex: pan handle which soil order is this

50%

how much of soil is solid material

dissolution

hydration of anions and cations until they dissociate ex: think of it as a salt CaSO4 + 2H2O + 2H2O <-> Ca SO4 + 4H2O (gypsum solid) <-> solution + water

6 biogeochemical weathering processes

hydration, hydrolysis, dissolution, acid reactions, oxidation-reduction, complexation/chelation

basic and fine

igneous rock - basalt is hint: formed extrusive acidic or basic fine or coarse

acidic and coarse

igneous rock- granite is hint: formed intrusive acidic or basic fine or coarse

slow and laterally

in a soil thats 2 meters deep, water will move _____ and _____ through a clay loam * capillary forces at work for the second blank

quickly

in a soil thats 2 meters deep, water will move _______ through sandy loam compared to clay loam

Gleysol

in a wetland area between the A and B horizon, might see an area that more red whats happening is the water table moves up and down, when it goes down oxidation occurs turning it red what soil order is this: hint its a german one

false

in general, colluvium would be better than sorted than alluvium true or false

how is lacustrine deposited in the environment

in lakes - silt and clay sized particles

20 to 30%

in soil, of the pore space how much is generally air? (same goes for water)

true

in the winter mulch acts as a blanket keeping the heat in winter : remember the time lag

hydration

intact water molecules bind to a mineral 5Fe2O3 +9H2O -> Fe10O14 + 9H2O (hematite +water = ferrihydrite +water)

the relationship between particle size and reactivity

largest particle = sand then silt smallest particle = clay surface area per volume increases as you move to smaller particles surface area, plasticity and reactivity all increase as size decreases sand and silt are spherical shape clay is plate like shape (even more surface area due to shape)

C horizon

least weathered

of the 8 most abundant elements in the earths crust: arrange them according to solubility over normal range of SOIL pH

least: -Ca, K, Na, Mg -O, Si -Al, Fe

true

limestone is a carbonate true or false

Fe, Ca, Mg, K

list 4 plant essential metallic elements that are most abundant in rock and minerals

thermal conductivity

looking at the way heat moves through the soil * think of them as atoms compact dry soil = good at transferring heat to surrounding particles - loses heat more easily (high K) loose soil = good thermal insulator (low K)

Soil Om

low in sand (high OM turnover rate) high in clay (clay protects OM (aerobic condition))

satiated

macro and micropores are filled with water matric potential = 0

saturated

macropores are filled with water matric potential = 0

regolith

made up of A to C horizons, the C horizon isnt really effected by climate/biota

solum

made up of only A and B horizons, is acted on by climate and biota

high Dp

magnetite and garnet have a __________ of 3.0g cm3

clay

make ups of particles: more secondary silicate minerals other secondary minerals little quartz some primary silicate minerals little to no primary minerals

sand

make ups of particles: mostly quartz some primary silicate minerals little secondary minerals

silt

make ups of particles: some primary minerals some secondary silicate minerals some other secondary minerals good amount of quartz

white

makes soil appear _____ uncoated quartz, calcite, gypsum, soluble salts

true

matric potential and tension are the same: to remove water it requires work mp = negative tension = positive

lateral

mechanical impedence: clay pan or compacted are or water table limits root growth cause root to go down and then to the side

thickening

mechanical impedence: root can still get through thickens before passing through the dense layer

corkscrew

mechanical impedence: root cant go anywhere else so it curls into or around itself

contortion

mechanical impedence: root grows lateral and then finds a place to go down through the dense layer

the disintegration of rocks due to differential expansion of minerals

mechanical weathering processes result in ____ which: -the hydrolysis of minerals through frost action -the oxidation of iron & manganese compounds -the decomposition of primary minerals -the disintegration of rocks due to differential expansion of minerals

sedimentary rock, limestone

metamorphic rock: marble is made up of

sedimentary rock, shale turns to phylitte which turns into ____

metamorphic rock: schist is made up of

sedimentary rock, shale

metamorphic rock: slate is made up of

biochemical weathering of rocks

microbes in plants are making acids and breaking down/ weathering rock plays the biggest role at the end of it all

mottled

mixed color due to oxidation and reduction described by the amount, size, contrast, and color - cause by high water table

% water (Pw)

moist soil weight / dry soil weight * 100

water and air

moist surface soils contain approximately equal parts by volume of _____ which: water & air OM & air mineral & organic matter mineral matter & water solids % air

stickiness

moisture content at which the soil adheres to the fingers and thumb - nonsticky - slightly sticky - sticky - very sticky * wet the soil (more clay = more stick)

Permanent Wilting Point (PWP)

moisture content of the soil at which plants wilt and fail to regain turgor overnight matric pot = (-) as plants loose water they wilt during the day, at night they recover the lost soil

plasticity

moldability of soil - non plastic - slightly plastic - plastic - very plastic * lots of sand little clay = lack of moldability

B horizon

more clay than the ___ horizon because it likes to travel

A horizon

more sand than the other horizons

capillarity

movement of water due to forces (adhesion and cohesion) h = 0.15 / radius - smaller radius = more water can be pulled up - larger radius = harder to pull more water up can be vertical and horizontal

Quartz

name 3 primary silicate minerals that are resistant to weathering and dominates the sand and silt fractions of most soils

Water holding capacity

not enough water, plants will die ex: want a soil with clay over sand

10%

of just the soil solids, what percent is OM?

true

of the incoming solar radiation: - some reflected by cloud and some is scattered by particles in atmosphere - some is absorbed by atmosphere (half makes it the the ground) what made it the the surface - only small % of the heat is absorbed by the soil during the DAY at NIGHT - soil loses heat

muck (sapric)

organic deposits: ____ : little fiber remain due to decomposition

peat (fibric)

organic deposits: ____ allows plant fibers to be identified

O

organic layer of soil is which horizon

organic deposits

organic material that accumulates in wet areas or really cold areas places where plant growth exceeds that rate of residual decomposition due to the lack of O2

oxidation reduction

oxidation : loss of e reduction : gain of e *end product are things we see in older soils 3MgFeSiO4 + 2H2O <-> H4Mg3Si2O9 + SiO2 + 3FeO (olivine solid) -> serpentine solid + solution + Fe(2) oxide ferrous iron ((hydrolysis) 4FeO + O2 + 2H2O <-> 4FeOOH (Fe(II) oxide ferrous iron) = goethite Fe(III) oxyhydroxide ferrous iron ferric iron (( -> oxidation )) (( <- hydrolysis))

which mineral group is most resistant to weathering

oxides made of Fe and Al - geothite - hematite - gibbsite

passive soil forming factor

parent material

five soil forming factors

parent material climate biota topography time

lacustrine

parent material deposited in lakes

true

plants have to exert the most energy to get water from clays (increase clay content = more neg matric potential) in loams they dont require as much energy to get water in sands they require the least amount of energy to get water

water

polar - reason it sticks to things - reason it has a high specific heat - connect to each other through H bonds

properties of water

polar h bonds cohesion adhesion

major components of a typical, moist surface soil

pore space (40 - 60%) - air (20-30%) - water (20-30%) soil solids (50%) - mineral (45%) - OM (5%)

what happens to liquid movement when it encounters large pores that are dry ex: clay loam (top) / sand (bottom)

pores have to be filled before water will make its way down

negative matric potiential

positive or negative matric potential water is absorbed so tightly to the particle its not a liquid any more the amount of work to be applied is so high = negative potential to remove the water (if is it easy to remove the water/ free water = 0)

acid reactions

presence of acids accelerates weathering processes with increase H ion activity in water CO2 + H2O <-> H2CO3 (carbonic weak acid) H2CO3 + CaCO3 <-> Ca + 2HCO3 (carbonic acid) + (calcite acid) = solution

what soil properties affect infiltration rates

rain events (slow rain = good infiltration) (lots of rain = flows over land with some infiltration) previous soil moisture

soil consistency

resistance to penetration by an object - measure of how much resistance is there when you try to penetrate the soil

physical weathering of rocks

results in the reduction of grain size ex: freeze, thaw ex: temperature, moisture, abrasion by wind/ice/water, animal and plant root pressures

importance of O2 in soil

root respiration aerobic respiration to decompose OM oxidation reactions (think about Fe) - roots get wet they will die due to lack of O2

drainage rate

sand = high clay = low (water likes to stick to clay due to the charge)

compactability

sand = large pores, when wet it compacts but doesnt stay clay = really plastic

eolian

sand dunes are an example of deposition of which parent material

leaching potential

sand has large pores to higher potential clay has smaller pores so lower potential

what kind of parent material is found in the northern part of texas near the pan handle

sandstone, siltstone, shales

gravity

saturated flow: movement of water when the soill is saturated or satiated - all pores are filled - movement via _____ and small capillarity

calcite and dolomine

sedimentary rock: limestone is made of ______ and ______

quartz

sedimentary rock: sandstone is made of

silicate clay minerals

sedmentary rock: shale is made of

hydrostatic potential

seen ONLY in saturated zones below the water table

volcanic ash particle sizes

silt and sand

clay

smallest of the particles, hard to see even under a microscope

diffusion

soil aeration: movement due to differences in partial pressures (more common) ex: CO2 wants to move from high concentration (soil) to low concentration (atmosphere) same goes for O2 but from atmosphere to soil

mass flow

soil aeration: movement due to differential total pressures (rare)

soft soil consistence

soil consistence crumble under slight force

hard soil consistence

soil consistence: can be compressed in hand

time

soil is finite during the human lifetime because it takes thousands of years to form. which soil forming factor is this

false

soil is interfaced with lithosphere through gases emissions and energy transfer true or false

ultisol

soil is no longer fertile, red in color, low base saturation which soil order is this

soil consistency

soil resistance to penetration by an object is the definition of

bulk density (Db)

soil soilds and pore space mass of total soil per volume weight of dry soil/ volume of soil * how compacted the soil might be *

parent material

soils is a dynamic natural body having properties due to the combined effects and biotic activity as modified by relief acting on _____ over time which: parent material pedon profile solum regolith

transported parent material

soils moved from location and deposited in another ex: colluvial, alluvial, coastal/marine sedimentation, glacial ice/melt waters, aeolian, lacustrine, volcanic ash

plate like

structure: - A and E horizon *mainly E

Prism-like (Columnar)

structure: - never want in a soil - soils have Na caps Na disperses soil particles creating gaps letting smaller particles fall through and water - B horizon - puddling of water due to gathering

prism like (prismatic)

structure: - striations occur - B horizon - length > width - they have clay, if there isnt enough clay it can form subangular blocky

grade

structure: 0, weak, moderate, strong how well it stays together when passed from hand to hand

spheriodal

structure: EXCLUSIVELY A ONLY - space between peds - water/ air movement = good - OM acts as a glue

angular blocky

structure: common in B horizon higher amounts of clay humid regions sharper edges

Spheriodal

structure: granular and crumb belong to ____ ped

structure less conditions

structure: massive: lots of clay makes a big clump -soils are important - low permeability once pores are full puddles form

structure less

structure: nothing is going on, all single grains

subangular blocky

structure: rounded edges - humid regions - A, E, B horizons - B = little to moderate clay content

blocky

structure: subangular and angular belong to which ped

size or class

structure: very fine, fine, medium, coarse, very coarse the more coarse the decrease in ability to hold nutrients

false

subsoil is roughly equivalent to the O horizon true or false

B horizon

subsoil; silicate clays, iron, and aluminium oxides, gypsum, calcium carbonate - plant roots - more clay - more compacted - larger aggregates - LESS OM

true

surface soil heats up and cools down during the summer - greater differences in temperature the deeper you go there is "lag time" it takes a while for the heat to make its way down there and it loses energy along the way - less differences in temperature

more porous

surface soils are more _____ than subsoils which: lighter in color more compact more porous more dense more clayey

soil structure

the arrangement of sand, silt, clay, and OM in soils plays a large role in how air and water flow through a system

soil

the collection of natural bodies occupying parts of the Earths surface that is capable of supporting plant growth and that has properties resulting from the integrated effects of climate and living organisms acting upon parent material, as conditioned by topography over periods of time

texture

the distribution of sand, silt, and clay particles determines a soils which: structure texture suture tester

Calcite (CaCO3)

the mineral is the most soluble and easily weathered in wet climate which: Calcite Quartz Hematite Feldspar apatite

matrix color

the most common color of the soil horizon in mottled soils is called

biochemical + physical

the order in which rocks are weathered is: which: physical -> biochemical biochemical + physical biochemical -> physical

silt and sand

the percentages of which soil components represent the MINIMUM information necessary to determine the textural class of a soil? which: sand, silt, clay sand and silt clay, water & air clay and OM gravel and sand

hydrolysis

the reaction below is an example of ______ 2HAISi3O8 + 11h2o <--> Al2O3 + 6H4SiO4 which: acid reaction hydration hydrolysis dissolution

feldspar

the silicate mineral is prone to weathering due to bases which: feldspar quartz goethite gibbsite calcite

pedon

the smallest volume that can be called a soil is ... hint: 3D

surface & subsurface soil

the solum consist of ____ which: surface & subsurface soil surface soil only A, B, & C horizons

true

the state soil of Texas is Houston black and is a Vertisol true or false

medium

the structural size of a horizon having a moderate, medium columnar structure is ____ which: moderate moderate, medium columnar moderate, medium columnar medium

0.002

the upper limit in equivalent spherical diameter for clay particles, according to the USDA system, is ____ mm which: 0.2 0.02 2 0.0002 0.002

transported and residual

there are 2 broad classifications of parent materials what are they

preferential flow paths

these are 2 types of : open to surface closed to surface - capillarity forces - gravity takes over ones its under ground * water wants to take the path of least resistance = open to surface

aggregates

these are types of ______ : granular prismatic subangular blocky platy

clay

this describes what particle : high water holding capacity poor aeration very slow drainage rate high to medium soil OM high compactability less(unless cracked) leaching potential

sand

this describes what particle : low water holding capacity good aeration high drainage rate low soil OM low compactability high leaching potential

A

this horizon: - less compacted (lower Db) - more sand and silt - smaller aggregates - darker due to OM

B

this horizon: - more compacted (higher Db) - more clay - larger aggregates - less OM

transported

this is an example of what kind of parent material: bring sand home with you from the beach

residual

this is an example of what kind of parent material: limestone isnt going to move, stuff is going to build and form soils on top of it or dead OM in swamps - creates Histosol - gets layered on top of one another

sand

this particle can be seen with the naked eye

silt

this particle size is similar to flour, cant be seen without a microscope

osmotic potential

this potential has little influence on the movement of water in soils but it does affect plant- soil water relationships ex: water wants to move from the root -> out due to there being more negative charges outside of the root

vertisol

this soil has lots of clay, found in areas with few trees, shrink-swell clays. particularly fertile- hangs on to & absorbs plant nutrients ex: SA which soil order is this

true

true or false Al and Fe are a small portion of rock but a larger portion of the soil large ratio: ex: 1.87, 3.42

true

true or false Dp > Db usually

true

true or false K and Ca are being lost from the soil small ratio: ex: 0.21, 0.14

true

true or false a soil to rock ratio that is larger than 1, something is being gained from the soil

true

true or false always have to mention moist or dry when writing soil color

false - reduction

true or false blue in soil - oxidation occuring

true

true or false clay hold more water due to reactive surfaces Om holds more water due to increase surface area

true

true or false deep soil = pulls more water up shallow soil = pulls less water up in example: the bottom of the tray where the water is being added has high energy the soil has low energy

true

true or false greatest to least porosity crumb granular subangular blocky angular blocky prismatic plate like structureless (massive)

true

true or false iron in soil - oxidation occuring

true

true or false lots of OM = low Dp Dp = 0.9 - 1.4 gcm3 OM makes it light and fluffy

true

true or false low fertility due to : low CEC (cation exchange capacity) low OM leaching (low water holding capacity) WHC sand soils are basically neutral, due to these things

true

true or false soil temp depends on the amount of heat energy absorbed - light soil = less than darker soils lots of water in soils = longer to heat little water = fast heat - sunlight can evaporate the water but it wont have enough energy to heat the soil

false- they do

true or false texture Om and structure DONT influence field capacity

true

true or false the more OM present in aggregates the greater ability the ped will hold shape when wetted

true

true or false the parent material, alluvium, is deposited in the coastal plains and is an example of coastal/ marine sedimentation

gravity

true or false water moves by capillary action (matric potential) EXCEPT when large pores are full then ______ takes over

true

true or false structure description: - grade, size, structure type ex: weak, coarse, subangular blocky

true

true or false soil texture greatly influences PWP

true

true or false weatherability of silicates: order olivine pyroxenes amphiboles Fe-mica feldspars Al-mica (clays) Quartz

Regolith

unconsolidated debris overlaying hard unweathered rock

capillarity

unsaturated flow: movement of water in soil when some of the pores (large) do not contain water - movement of water via ______

surface soil

uppermost loose layer, has OM, completely unweathered, dark brown color

enchanted rock is made of what kind of parent material - its located in south, central texas

volcanic

true

water has a high specific heat dry soil has a low specific heat when a soil is wet it doesnt heat or cool down quickly soil will maintain a higher temp when moist (wet soils store more heat during the fall months) wet soils require more energy to heat during the spring

hygroscopic water

water held so tightly that its considered "non-liquid" - will not move via capillary action once PWP is reached water is held so tightly to particle it is unable to be reached by plant

gravitational water

water in the largest pores will move due to gravity

hydrolysis

water molecules split into H and OH components H = replaces cation in mineral structure (water disappears) KAlSi3O8 + H2O -> HAlSi3O8 + K OH (solid) = solids + solution

high(0) to low(-)

water movement due to matric potential: from _____ to _____ potential

true

water moves from sites of high matric potential to low OR (low tension sites to high tension sites) true or false

adhesion

water sticking to a surface ex: solute in solution (NaCl)

surface tension

water wants to stick together which creates _____ reason bugs can float on water

cohesion

water wants to sticking to another water molecule

most

weatherability of silicates: basic or mafic minerals are _____ weatherable

least

weatherability of silicates: acidic or siliceous minerals are ____ weatherable

feldspars, amphiboles, pyroxenes, and micas

what are the 3 primary minerals that weather to form clay in soils

climate and biota

what are the active soil forming factors

air, water, minerals, OM

what are the four components of soil

parent material

what are the passive soil forming factors

any material of glacial origin

what is glacial drift

topography

what is the modifying factor when soil is forming?

limestone

what is the parent material for san antonio

volcanic

what kind of parent material is found in the western part of texas

Vertisol

what kind of soil order is considered a "shrink-swell clay"

OM and mineral matter

what makes up soil solid material

loose soil consistence

what soil consistence: cant break/ rupture easily

subsurface flow

when water hits a clay pan it cant get through so it flows under the surface what is this called

structure

when you read "arrangement" think of sand silt and clay

texture

when you read "distribution" think of sand silt and clay

true

when you remove whole trees you can expect warmer soil temps there when you leave the stems : less warm when you remove stems and soil is compacted = coolest trees act as mulch layer in a way

Blackland Prairie region of Texas

where is Houston Black soil found

A

which horizon is typically the darkest

B

which is greater? Both are 1 cubic meter A = 1.33Mg (solids and pore space) B = 1.33Mg (solids) which makes up half, the other half is pore space.

all of the above

which of the following are functions of soil? Medium for plant growth Regulates water flow Habitat for soil organisms Recycler of raw materials Modifier of the atmosphere engineering medium All of the Above

10

which of the following pH values represents the most alkaline condition which: 10 7.0 6.0 5.0

true

wilting coefficient (PWP) increases as texture becomes finer

eolian (loess)

wind carried silt size particles - can be a factor of glaciation