GC 202 Exam 1
a __ indicates a bisequal designation
' (prime)
a __ is used to separate 2 master horizon letters, 2 master horizon components are recognizable in the horizon and at least 1 of the component materials is ___ by the other A/B
/; surrounded
every ___degrees celsius rise in temperature, the rate of biochemical reactions more than _____
10; doubles
how many diagnostic subsurface horizons are there
19
dominant horizon (strongest properties) listed ___, followed by subordinate horizon (AE)
1st
composition of soil 45%? 25%? 25%? 5%?
45: mineral matter (rock) inorganic 25: water (pore spaces) 25: air (pore space) 5: organic matter
how many STRs
6
how many soil moisture regimes
6
Residual parent materials are best described as _____ Select one: a. materials formed by weathering of rocks and minerals in place. b. materials formed under organic residues. c. materials more dominant in Iowa than in the Southern United States. d. materials transported from one location to another by water, ice or wind. e. materials formed exclusively from agricultural practices.
A
a master horizon consisting of organic material and mineral matter (Mineral>organic); darker colors; top soil
A horizon
a master horizon which is the zone of accumulation of clays, iron, and Al oxides, gypsum, or CaCO2; color staining; (<org)
B horizon
a master horizon that is relatively unweathered, unconsolidated parent material (some microbes and roots)
C horizon
The amount of different sizes of mineral particles in a soil defines the soil _______. Select one: a. pore space b. solution c. texture d. profile e. structure
C texture
what is the acronym for soil formation
CLORPT
The mixed angular gravel, rock, and soil found at the foot of a slope (think gravity!) is typical of what type of parent material? Select one: a. fluvial b. lacustrine c. galcial d. eolian e. colluvial
E
forest vegetation and high rainfall will form a leached __ horizon
E
a master horizon that is the leached zone; lighter color
E horizon
Depth of weathering will be greater in a soil found on a hillside when compared to a soil found in an adjacent flat area. Select one: True False
False
Soil air usually has a lower carbon dioxide content than the air in the atmosphere. Select one: True False
False
The ochric epipedon is usually soft and dark in color due to it's high abundance of organic matter. Select one: True False
False
a master horizon consisting of undecomposed or decomposing organic matter, usually at the surface of forest soils
O horizon
What are the soil master horizons in order?
O, A, E, B, C, R
Brevort sandy over loamy, mixed, nonacid, firgid Mollic Haplaquent ...soil taxonomy?
Order: ent Suborder: aqu great group: hapl subgroup: Mollic family: sandy over loamy, mixed, nonacid, frigid series: Brevort
a master horizon that is rock, parent material
R horizon
Climate influences not only the rate of weathering, but also the type of native vegetation dominant in an area. Select one: True False
True
Eluviation (leaching) of clay, iron, and other materials is the principal process responsible for the formation of an E horizon. Select one: True False
True
The number "2" is used before the master horizon letters to identify horizons that developed in a different parent material. Select one: True False
True
The perudic soil moisture regime occurs where precipitation exceeds transpiration and where water will move through soil every month of the year. Select one: True False
True
A ____________ refers to when two master horizons with the same master horizon designation (letter) develop in a profile and are separated by an unlike master horizon. Select one: a. Bisequal designation b. Transition horizon c. Translocation d. Subordinate distinction
a
The soil process that referers to redoximorphic modification of iron from the more soluble Fe(II) state to the more insoluble Fe(III) oxidized state within the B horizon is best described by which one of the following soil formation processes? Select one: a. Transformation b. Translocation c. Loss d. Addition
a
Which type of biome do you expect to have the darkest (more organic matter) and thickest A horizon? Select one: a. Grassland b. Tundra c. Steppe d. Forest
a
what is the Huangtu Geoyuan (Loess plateau)
a loess deposit in N china
soil water is not sufficient to leach in arid or semi-arid climates, so what is created?
a thick, hard crust at soil surface or concrete-like layers in subsoil
when growth of plant material exceeds the rate of decomposition, plant residues ____, sink into the ___ and slowly ____
accumulate;water;decompose
materials added to soil profile from outside sources; adds onto soil (moves down); ex, leaf litter (OM), eolian influx (dust), ground water influx via capillary action (salts, pollution)
additions
very fine particles that are suspended in the atmosphere, deposited with rainfall in small amounts
aerosolic dust
how do humans modify soil formation
agriculture, fires, habitat alteration, development
held within soil pores, very within soil; high relative humidity is common; CO2 is higher than CO2 in atmosphere
air
diagnostic surface horizon: white, under forest, light colored E
albic
deposits by action of running, channelized water (floodplains, alluvial fans, delta)
alluvial
2 new soil series added since 1975
andisol, gelisols
formed from volcanic materials
andisols
epipedon "human" mollick like but human made, irrigated agriculture or long term human residence
anthropic
SMR: soil is saturated; reducing conditions exist; gleying and mottling; artificial drainage for crops
aquic
diagnostic surface horizon: 1.2x as much clay as horizon above, B horizon, illuviation of soil clays
argillic
which climates lack effective precip
arid and semi-arid
SMR: soils are dry more than 1/2 the growing szn and moist for less than 90 consec days; arid climates; irrigation need to grow crops
aridic (torric)
Very dry soils with ochric epipedons and sometimes natric subsurface horizons
aridisols
In a given area, effective precipitation will be the greatest at which of the following locations: Select one: a. a flat area at the top of a hill b. on a flat area at the base of a hill c. on a mound d. on a steep slope.
b
The soil temperature regime where mean annual soil temperatures are between 0oC and 8oC, and where summer temperatures do not exceed 15oC is called: Select one: a. Thermic b. Cryic c. Perigelic d. Frigid e. Mesic f. Hyperthermic
b
When you detect a horizon that shares properties with the adjacent B horizon (below) and E horizon (above), where the E horizon properties are most abundant and are also surrounded by the less abundant B horizon properties. Select one: a. EB b. E/B c. BE d. B/E
b
Which type of biome do you expect the highest degrees of weathering (deepest depth) to occur? Select one: a. Savanna b. Tropical Forest c. Tundra d. Temperate Forest
b
hard, relatively un-weathered rock
bedrock
biosequence
biota
living organisms (plants and animals) in soil
biota
2 horizons may develop in a profile and have the same horizon designation but are separated by an unlike horizon
bisequal designation
where do you expect to find the deepest depths of soil development, on the slope or at the bottom? why?
bottom bc it has deeper layers, greater difference between horizons, (on the slope is thinner and weaker horizons, less developed)
what does tunneling animals do for the soil
brings materials to surface (aerate soils), adds OM, refills tunnels with new materials
Ab =
buried
In which of the following horizons has the process of illuviation (accumulation) most likely occurred? Select one: a. A b. C c. B d. E e. O
c. B
diagnostic surface horizon: B horizon, illuviation of Ca or Mg carbonates, white chalky zone
calcic
when weak acids break down rock
carbonation
smallest particles; hard clods when dry; adhere together to from a sticky mass when wet
clay
climosequence
climate
long term weather of a place
climate
most influential of the soil forming factors is
climate
what does ClORPT stand for
climate, organisms, relief, parent material, time
result from mass wasting (fall and creep) which result from downslope movement of weathering
colluvial deposits
what are 5 geomorphic processes of transported parent material
colluvial, alluvial, lacustrine, glacial and glaciofluvial, eolian
Bhs =
combo of s and h
biological activity produces acids and causes weathering
complexation
soil ___ is so important because it will not be renewable without proper management
conservation
what are organic pockets in the B horizon formed when tunnels formed by tunneling animals fill with new materials
crotovina
STR: mean annual soil temp 0-8C w/ summer temps <15C
cryic
Specific characteristics within a horizon are indicated with lowercase letters that follow the master horizon designation are called: Select one: a. Bisequal designations b. Diagnostic horizon c. Transition horizon d. Subordinate distinctions
d
The process of silt illuviation from the E to the B horizon is best described by which of the following soil formation processes? Select one: a. Addition b. Loss c. Transformation d. Translocation
d
"Topsoil" is generally equivalent to which soil horizon? Select one: a. C b. B c. E d. A e. D
d. A
unsorted, unstratified mixture of all sizes (boulders to clay) landforms are moraines, drumlins, and till plains
diamicton
when water dissolves rock material
dissolution
chemical weathering could be (4)
dissolution, carbonation, oxidation, complexation
in low lying areas, surface water flow may be impeded, creates ponds and/or wetlands
drainage
sediment of glacial origin
drift
moving hills of wind-blown fine and medium sand or formed long ago but no longer active and covered by vegetation
dune sand
diagnostic surface horizon: hard and imprevious, cemented by illuvial silica; does not dissolve in water or HCl acid
duripan
what kick started soil classification and conservation
dust bowl
amount of water percolating thru the soil profile
effective precipiation
deposits transported by wind
eolian
differentiated based on particle size, mineralogical class, cation exchange capacity, STRs
family
Oi =
fibric or litter
diagnostic surface horizon: brittle and dense, does not soften when wet; can be broken with hands
fragipan
Bx =
fragipan, firm, brittle, dense
STR: mean annual soil temp 0-8C w/ summer temps > 15C
frigid
deposits related to action of glaciers
glacial
which type of biome has a deeper and thicker A horizon grassland or forest?
grassland because lots of organic matter added to them due to root systems of grassland plants
coarse fragments that are NOT used to determine texture are (3)
gravel, cobble, rock
3rd layer (1st listed) of formative elements used as root words ex: HAPLaquent
great group
____the temp, ___the biochemical reaction rates
greater; greater
____ the depth of water infiltration, ___ the depth of weathering and soil development
greater;greater
Oa =
hemic or fermentation
sedges, reeds, cattails, etc
herbaceous peat
epipedon "tissue", peat or muck, form in wetlands
histic
Peat or muck with greater than 20% organic matter content
histosols
leaching carries soluble and suspended material from upper to lower profiles (E to B) in this climate
humid
STR: mean annual soil temp > 22C
hyperthermic
3 common subordinate distinctions for O
i, a ,e
Bh =
illuvial accumulation of OM
Bk=
illuvial carbonate enriched
Bt =
illuvial clay enriched
Bs =
illuvial iron and aluminum oxide rich
prefix used with frigid, mesic, thermic and hyperthermic, if the difference between the mean summer and winter temps is less than 5C
iso
deposits laid down by large bodies of water (marine/ocean, freshwater or saline lakes)
lacustrine
conifers recycle ___ nutrients so they have a ___ soil acidity and ___ leaching
less; high; more
boundary between soil and continuous coherent material (rock) that is very hard
lithic contact
what are the soil sequences surrounding the eben ice caves
lithosequence and toposequence
deposits of wind-blown silt
loess
removal of material from soil profile; moves down ex, ground water leaching, surface erosion, fires
losses
epipedon that is a mineral horizon that is very black, v light weight and fluffy, derived from volcanic ash pm
melanic
STR: mean annual soil temp 8-15C
mesic
use iso for ___,___,___, and ___ if the difference between the mean summer and winter temps is less than __C
mesic;frigid;thermic;hypothermic;5
inorganic material derived from weathering and erosion of rock
mineral
epipedon that is thick, soft, high OM, dark, under prairies and grasslands
mollic
what are the 7 epipedons
mollic, umbric, ochric, melanic, histic, anthropic, plaggen
Very fertile (high base saturation) soils, common under prairie grasslands, with dark A horizons
mollisols
the more water, the ___ weathering
more
S facing slopes in N Hemi receive ____ direct sunlight = ___, ____, more ____, vegetation is _____, ___well developed soils
more,drier, warmer, more, sparse, less
deciduous trees recycle ___ nutrients so they have a ___ soil acidity and ___ leaching
more; lower; less
from mosses (like sphagnum), acidic, holds a lot of water
moss peat
plant fibers are unrecognizable in this organic deposit
muck (sapric)
epipedon that has a mineral horizon that is thinner, lighter, or too low in OM to be mollic or umbric; hard and dense when dry
ochric
indicated by presence/absence of major diagnostic soil horizons and other properties
order
soil taxonomy order from highest (broadest) to lowest (most specific)
order; suborder; great group; subgroup; family; series
how is effect of time different for organic soil than for mineral soil formation?
organic accumulates from parent material, mineral is formed by weathering of parent material
living or dead organisms and other organic compounds
organic matter
deposited by glacial meltwater; layered deposits of sand and gravel; form on the margins of retreating glaciers; landforms are eskers, movlin kames, kame terraces, and kettles
outwash
diagnostic surface horizon: highly weathered, wet tropical and subtropical areas, v high in Fe and Al oxides
oxic
water and air destabilize metallic minerals
oxidation
highly weathered soils common in tropical climates
oxisols
2 common subordinate distinctions for A
p, b
stream valleys may expose a variety of? (rock river, silver creek canyon near eben jct.)
parent material
what is the building block of soil
parent material
when a # FOLLOWS the master horizon letter, it means variation other than _____ (subtle change in __ or __)
parent material; color; structure
plant fibers can be identified in this organic deposit
peat (fibric)
3D structure (Minimum 1 m2 surface up to 10 m2) that contains all the properties of the studied soil
pedon
smallest sampling unit to display full range of properties characteristic of particular soil; 3D unit; range from 1-10 m2
pedon
burrowing mammals (gophers, moles, prairie dogs) cause soil mixing aka
pedoturbation
STR: mean annual soil temp <0C
pergelic
SMR: precip exceeds evapotranspiration; water will move thru soil every month; harvesting and curing crop difficult bc xs rainfall
perudic
not official within series, denoting slope, surface textures, or presence of rocks
phases
new series added
picture rocks grandsable series
epipedon "sod" human-induced, years of manure additions
plaggen
Ap =
plowed
lithosequence
pm
soil formation begins with fresh ___
pm
when a # PROCEEDS master horizon letter, it means either change in ___ or a ___ discontinuity
pm; textural
group of similar pedons, forms a discreet geographic unit or landscape component
polypedon
Ew =
poorly developed but noticable leached zone
C subordinate
r
scarcity of soil water causes discontinuous vegetation cover in some arid and semi-arid ___
rangelands
soil formation is ____ in warm, wet climates
rapid
unconsolidated material containing weathered rock and soil material
regolith
parent material formed in place from the weathering of rock
residual
3 main types of parent material
residual, transported, organic
subordinates for B
s, h, hs, t, x, k
large enough to be seen by naked eye; gritty when rubbed
sand
smaller particles that are used to determine soil texture are (3)
sand, silt, clay
Oe =
sapric or humified
remains of aquatic plants (algae) and from fecal material from aquatic animals, beginning of wetland succession
sedimentary peat
subdivisions of families; names based on geographic place; mappable units
series
too small to see without microscope; feels smooth but not sticky
silt
polished, grooved surfaces that occur along shear planes within soil, result from shrink-swell action of clays
slickensides
soil formation is ___ in cool, dry climates
slower
the colder the soil, the ___the decomp of the om
slower
the wetter the soil, the ___ the decomposition of the organic material
slower
topography influences (5)
soil loss, water inflitration, drainage, local climate, parent material
based on estimates of depths to which a known amount of water will wet in a certain amount of time and under certain tempearture restrictions
soil moisture regimes
vertical section exposing layers of horizons of a soil
soil profile (solum)
similar soil individuals that share a certain range of properties and characteristics as recognized by the NRCS soils division
soil series
each soil has temperature characteristics that can be measured over the course of several years to obtain mean annual and mean summer temp and the diff between the mean summer and winter temps
soil temperature regime
size of particles that make up soil
soil texture
diagnostic surface horizon: dark om rich, illuviation of humus
sombric
diagnostic surface horizon: wood ash, under albic, illuviation accumulation of free Fe and Al sesquioxides, humid continental climates
spodic
reddish brown and accumulated diagnostic subsurface horizon
spodic
designated using numbers to indicate variations within a master horizon
subdivisions
names used as adjectives that modify great group names ex: TYPIC haplorthod
subgroup
a formative element (or word root) used in naming, but it is in conjunction with the order's root (also formative element) ex: haplAQUent
suborder
based on soil properties that reflect major environmental controls on current soil forming processes
suborder
used to indicate specific characteristics within a master horizon
subordinate distinctions
physical weathering could be (3)
temperature, water, plants
STR: mean annual soil temp 15-22C
thermic
the slower the decomposition rate, the ____the O layer
thicker
full blown profiles with B horizons take ____ years to form
thousands
deposited by glaciers
till
through ___, soil forming factors interact with each other and create soils
time
chronosequence
time an development
configuration of the land surface in terms of elevation differences, slope, and landscape position
topography
toposequence
topography
4 major processes of soil genesis
transformation, translocation, addition, losses
soil constituents are modified or destroyed and others synthesized (physical or chemical); moves horizontally within a horizon ex, mineral weathering, organic matter breakdown
transformations
horizons with properties of the adjacent horizon, indicated using master horizon letters in combination together
transition horizons
other materials are ___to deeper zones of the soil
translocated
mvmts of inorganic and organic materials from one horizon to another, either up or down, usually by water ex, leaching, animal activity
translocations
deposits that result from erosion and mass wasting of sediment
transported
put in order from deepest to shallowest (tundra, boreal forest, steppe, desert, savanna,tropical forest)
tropical forest, boreal forest, savanna, steppe, desert, tundra
SMR: soil moisture sufficiently high in most years to meet the needs of plant growth; humid climates; adequate moisture to grow crops at any time soil temps allow
udic
epipedon that is similar to mollic and has low soil feritility
umbric
as materials are added to the ____ part of the profile, the soils begin to differentiate
upper
SMR: soils dry for 90 or more consec days; intermediate between udic and aridic; 1 or 2 rain fed crops per year may be grown but lack moisture part of year
ustic
climate will strongly influence natural ___
vegetation
High swelling in clays with deep cracks
vertisols
pyroclastic material ranging from cinder chunks to fine ash
volcanic ash
only subordinate for E
w
held within soil pores, contains dissolved organic and inorganic substances; pH is critical
water
combination of what is key for soils?
water and temperature
Cr =
weathered rocks inclusions
woody remains of trees and shrubs, end stages of wetland succession
woody peat
4 types of peat
woody, moss, herbaceous, sedimentary
SMR: dry in all parts more than 45 consec days; moist in all parts greater than 45 consec; found only in mediterranean climates (dry summer, moist winter); crops grow in spring
xeric