NRES 255 Exam 1
Given the Munsell color notation, 10 YR 5/3:
10 YR is the hue, 5 is the value, and 3 is the chroma
% pore space formula
100 - (bd/pd x 100)
Given the Munsell color notation, 10 YR 5/2:
10YR is the hue, 5 is the value, and 2 is the chroma
Given the Munsell color notation, 10 YR 5/4:
10YR is the hue, 5 is the value, and 4 is the chroma
Which class of land in the Land Capability Class System describes a soil that has moderate limitations or may require moderate conservation practices but is still suitable for row crops such as corn and soybeans?
2 (II)
go over question 25 in fall 2019
A
Assume that you have an ideal silt loam soil. What are the soil components that makeup A-D assuming the pie chart below is representative of their relative fractions? (a&b are 25%, D is like 45% and C is about 5%)
A and B = air and water C = organic matter D = mineral particles
How do you determine whether the soil is oxidized or reduced based off of the color description?
A chroma value of 2 or less means reduced and greater than 2 is oxidized. Think that since 2 is a low number, its reduced (or think of 2% reduced fat milk)
Catena
A sequence of different soil profiles down a slope. Climate doesn't change, but topography can change from one end of the catena to the other.
What are the two most common soils in Indiana?
Alfisols and Mollisols
The youngest soils in Indiana are found in which area?
Along the river floodplains
A soil horizon with clay accumulation is called a/an
Argillic horizon
Ultisols (ult)
Argillic or Kandic horizon, low base saturation. Light colored A horizon and clayey B horizon
Heavy vehicle traffic on wet soils may cause soil
Bulk density to increase and a platy structure to appear in the A horizon
Land capability classes
Class I - Heavy Cropping Class II - Moderately Heavy Cropping Class III - Moderate Cropping Class IV - Occasional Cropping Class V - Pasture Land Class VI - Pasture Land Class VII - Woodland Class VIII - Recreational, Natural Parks, etc. NOTE: No tillage or cropping after Class IV
What kind of soil texture has the highest water holding capacity?
Clay
______ describes soil particles which have formed into vertical pillars with rounded tops and high sodium, separated by miniature, but definite, vertical cracks in the B horizon.
Columnar
Which of these soils would likely have the lowest bulk density?
Cryofolists
Glacial Outwash
Described as having a stratified coarse and gravelly coarse texture. It is carried by water
Aridisols (id)
Dry soil, subsurface horizons usually have free salt accumulation
Of the following (Argiudox, Hapludid, Umbriorthel, Dystrochrept), which would you most expect to find in Central Indiana?
Dystrochrept
The taxonomic class of the Eastport soil series is a Mixed, frigic Spodic Udipsamments. What is the soil order of this series?
Entisol
The taxonomic class of the Westport soil series is a Mixed, frigid Spodic Udipsamments. What is the soil order of this series?
Entisol
Rank the following soil orders Alfisol, Entisol, Inceptisol, Oxisol, Ultisol, from youngest (least weathered) to the oldest (most weathered):
Entisol, Inceptisol, Alfisol, Ultisol, Oxisol
Diagnostic horizons are inherited from the parent materials
FALSE
What kind of iron is reduced?
Fe2+, also known as ferrous iron. The soil appears to be a dully gray color
What kind of iron is oxidized?
Fe3+, also known as ferric iron. The sol appears to be a bright (yellow, browns, reds) color.
Andisols (and)
From volcanic ash, minimal horizon development and known for shrinking and causing cracks the first time it dries
The kind of structure that would best promote root penetration and development is:
Granular
Given these 4 great groups (Halpaquand, Haplocalcid, Hapludalf, and Haplorthox), which of these soils is most likely to have a Ck horizon?
Haplocalcid
A somewhat poorly drained soil is one that:
Has grey mottles above 18" in a mostly brown background
Inceptisols (ept)
Has ochric or umbric epipedon and a cambic horizon (endopedon). Has a Bw horizon and is usually forest vegetation.
Alfisols (alf)
Have an A horizon, well developed B horizon with clay accumulation. Argillic, natric or kandic horizon (this is why it's so similar to Ultisols).
What does the base saturation say about the weathering and pH of the soil?
High % Base Saturation = higher soil pH, less weathering Low % Base Saturation = lower soil pH, more weathering
You are considering buying a parcel of land and notice that the color of the soil is 10 YR 3/1. The Land Capability class of this soil is likely:
IIw
Which class of land in the Land Capability Class system is the last class suitable for cultivated crops, but usually cannot be considered suitable to row crops such as corn and soybeans?
IV
How do you correct temperature for hydrometer readings?
If the temperature is above 20 degrees celsius, add 0.4 for every degree. If it is below 20 degrees celsius, subtract 0.4 for every degree it is below 20.
Cold temperatures (35 degrees F):
Increase organic matter accumulation
How does a more compacted soil affect the bulk density?
Increases it
Under the heading for each type of parent material are listed various transporting agents. Select the letter of the answer which correctly indicated the correct set of transporting agents for all parent materials
Lacustrine = water Alluvium = water Till = glaciers Colluvium = gravity Aeolian = wind
soil temperature and time graph (the top line is A, then B, then C). Which line most likely represents the poorly drained (wet) silt loam with straw mulch?
Line C
Entisols (ent)
Little profile development, ochric epipedon is common, no B horizon development
Given these 4 great groups (Melanaquand, Haploboroll, Orthohaplel, Petrocalcid), which of these soils is likely to have a low bulk density and is high in silicates, organic matter, iron, aluminum and other metals.
Melanaquand
Assuming you have an ideal silt loan, what soil component typically makes up the largest/fraction of the soil?
Mineral
Mollisols (oll)
Mollic epipedon, high base saturation, dark soils, some with argillic or natric horizons. Poor drainage and high in organic matter
All of these soil orders are found in well drained forest soils except:
Mollisols
What can be added to the soil to cool the temperature?
Mulch and plant residues
The ____ is the unmixed surface soil horizon where partially decomposed material (e.g., leaf litter) accumulates
O horizon
Oxisols (ox)
Oldest most highly weathered, high concentration of iron and aluminum oxides, has an oxic horizon
A soil containing predominantly ferrous iron throughout the upper 40 inches of the soil profile would be:
Poorly drained
What is the major physical difference between Prairie and Forest soils?
Prairie soils are typically deep and dark, while forest soils are lighter and more brown.
You have a soil that has hard bedrock (e.g., sandstone) as the parent material. What is the most appropriate master horizon to describe this parent material?
R horizon
A soil particle measures 0.07mm, it is:
Sand
Which soil texture has the lowest water holding (storage) capacity?
Sand
Given the textural triangle below, what is the soil texture for a soil containing 60% sand, 10% silt, and 30% clay?
Sandy Clay Loam
Vertisols (ert)
Shrink-swell clays and has 45 degree angle slickensides in the B horizon
A soil particle measures 0.009mm, it is:
Silt
Loess is a common parent material for Midwestern soils. The most common surface texture from loess is:
Silt Loam
The oldest soils in Indiana are found in which area?
South central
Spodosols (od)
Spodic horizon commonly with Fe, Al oxides and humus accumulation. Horizons are identified by Bs, Bh, or Bhs
What horizon undergoes Iluvial processes? And what is it described as?
The B Horizon undergoes this, and it's when iron and clay go INTO the B Horizon. Elluviation and Illuviation are part of a process called Translocation.
Stokes Law
The Boyoucous Hydrometer is influenced by this law. It describes speed at which particles of sediment drops based on radius and density; bigger particles drop faster. After 40 seconds, the sand settles, and after two hours, the clay can be measured
What horizon undergoes Eluvial processes? And what is it described as?
The E Horizon undergoes this, and it's when iron and clay EXIT the A and E horizons.
How does topography affect soil?
The steeper the slope the thinner the soil, and it controls the runoff of water
What do diagnostic horizons do?
They help determine soil order and are not determined by parent material
Two Indiana soils, one a residuum and one an alluvium would likely differ in which soil forming factors?
Time and parent material
______ is the soil forming factor that causes soils to differ within the same catena
Topography
Colluvial
Transported by gravity and is common in mountain areas
Aeolian
Transported by wind and makes up Loess and Dune Sand.
The Hobbit silt loam is a fine silty, mixed mesic Typic Fragiudalf. What is the subgroup?
Typic Fragiudalf
The Hobbit silt loam is a fine silty, mixed mesic Typic Fragiudalf. What is the suborder?
Udalf
Which of the following would you least expect to find in Indiana?
Umbriorthel
Which class of land in the Land Capability system describes a soil that has severe limitations and would likely only be suitable for recreation, wildlife, or aesthetics is?
VIII
What area has Gelisols?
Very cold climates and typically contain permafrost
How does climate affect soil?
Water and rain will promote weathering of the soil. Warmer conditions allow chemical and biological reactions to occur, which causes the parent material to become soil.
What was the name of the most recent glacial advance (glaciation) that impacted the Purdue campus (and much of Indiana)?
Wisconsian
Histosols (ist)
almost entirely organic matter
As soils are weathered, they do all of the following except:
become more basic (base saturation increases)
What does the lowercase k mean?
calcareous
What does the lowercase t mean?
clay accumulation
A soil which will form a strong ribbon and feels gritty (but less than 50% sand) would most likely be a:
clay loam
Which of these are soil forming factors?
climate, topography, parent material, time, and vegetation/biotic
As % pore space increases, bulk density:
decreases
As soils are weathered, they:
develop more horizons
bulk density formula
dry weight / volume
land capability subclasses
e = risks of erosion w = wetness, drainage, or flooding s = solum - root-zone limitations (e.g., acidity, density, shallowness, stoney, sandy) c = climate limitations (e.g., short growing season)
What does the lowercase x mean?
fragipan
Lacustrine
from lake deposits and are formed by strata (layers) of silt and clay. It is transported by water.
What does the lowercase g mean?
gleyed
Given blocky, granular, massive, and platy, in what order would you expect to find these structures in a well-drained forest soil profile (from top to bottom)?
granular, platy, blocky, massive
What does hs mean?
humus and iron accumulation
As % pore space decreases, bulk density:
increases
What does the lowercase s mean?
iron accumulation
The tan/brown/red color in a mineral soils is caused by the
iron content
How do you determine order, suborder, great group and subgroup from the given name?
last two or three letters indicate order, then the next 4 or 5 to the left tell suborder, then the entire second word is the great group, and finally, the first and second word is the subgroup.
A soil which will form a weak ribbon and feels gritty (but less than 50% sand) would most likely be a:
loam
In the spring and summer when it is warm and humid:
organic matter breakdown increases
How does pH differ in young and old soils?
pH is lower in old soils, meaning old soils are more acidic
what does the lowercase p in the sub horizon mean?
plowed
What causes poor soil aeration?
poor soil drainage
You measure the diameter of a soil particle and find that it measures 0.02mm. This particle is most likely a:
silt particle
You measure the diameter of a soil particle and find that it measures 0.03mm. This particle is most likely a:
silt particle
Given the textural triangle, what is the soil texture for a soil containing 10% sand, 60% silt, and 30% clay?
silty clay loam
Which soil texture has the highest water holding capacity?
silty clay loam
Classifying a soil by physical and chemical properties is an example of:
soil taxonomy
Massive and single grain structureless are most likely found in:
the C horizon
pore density
typically calculated as 2.6 gr/cm3
What does the lowercase w mean?
weakly developed (this is for horizon description)
A soil containing only ferric iron throughout the upper 40 inches of the soil profile would be:
well drained (key word is ferric)
