exam 1

Question 1

What are the 12 soil orders

Answer 1

lfisols
Andisols
Aridisols
Entisols
Gelisols
Histosols
Inceptisols
Mollisols
Oxisols
Spodosols
Ultisols
Vertisols

Question 2

What are the 6 roles soils have to play?

Answer 2

1) Medium for plant growth
2) Recycling system for nutrients and organic wastes
3) Habitat for soil organisms
4) Modifier of the atmosphere
5) Engineering medium
6) System for water supply and purification

Question 3

What do soils provide for plants?

Answer 3

Physical Support

Aeration for roots

moisture supply and storage

Moderation of root zone and near-ground air temperature

An environment relatively free of phytotoxins

Supplying nutrients essential for plant growth.

Question 4

What in the water cycle is affected by soils?

Answer 4

Water loss
utilization
contamination
Purification

Question 5

What is a pedosphere and how does it act as an environmental interface?

Answer 5

A pedosphere is the top layers of soils that interact with the lithosphere, atmosphere, hydrosphere, and the biosphere
The pedosphere acts as an environmental interface due to the fact it is a medium in which all can interact with one another (where they all meet)

Question 6

Give the definition of soil structure

Answer 6

Soil structure combines or arranges primary soil particles into secondary particles, units, or peds. It can be arranged in the profiles to give a distinct characteristic pattern.

Question 7

Structured Soil Structures and what horizon are they common in?

Answer 7

Granular (porous)/Crumb (Very porous) - Characteristic of the A horizons.

Plate-like (Platy) common in E horizons but can occur in any part of the profile

Block like (Angular)/(Subangular) blocky common in B horizons.

Prism Like (Rounded tops) Columnar/ (flat, angular top) Prismatic Common in B horizons’
Wedge and lenticular

Question 8

What are peds?

Answer 8

Units of soil structures are called peds. Peds are natural groups primary particles (sand, silt, clay, and humus) that occur and persist within the soil.

Question 9

Soil Organic Matter or SOM - what is it made out of and give definition

Answer 9

The part of soil made up of decomposed plants and animals is considered SOM
It makes up 5% of soils dry weight (10% organisms, 10% roots, & 80% Humus)

Question 10

Unstructured Soil Structures and what horizon are they common in?

Answer 10

Massive - Lacks visible structure, appearing as a dense, solid mass - Common in the B horizon
Single Grain

Question 11

Define soil quality

Answer 11

The ability of soil to function as part of the environment (the ability of a soil to carry out ecological functions)

Question 12

Why is water and air important for plant growth?

Answer 12

Water and air are important for plant growth because water helps plants take in nutrients and stay firm, while air provides oxygen for the roots to breathe and carbon dioxide for making food.

Question 13

What are the principle causes of soil color?

Answer 13

Organic matter (darkens soils)-Decomposed plant matter
Iron oxides
Oxidized iron (Fe+++) reds, browns, tans and yellows
Reduced iron (Fe++) grays

Carbonates (Impart whitish colors)

Question 14

Munsell Color Chart what is it?

Answer 14

A resource soil scientists use to describe a soil’s color
-various colors are shown on a card to compare to the soil sample you have

Question 15

Give the definitions of Hue value and chroma regarding the Munsell color chart.

Answer 15

Value is how light or dark a soil can be with 0 being black - On a Munsell chart the value is vertical

Chroma is how intense or bright the soil is with 0 being grey - On a Munsell chart the Chroma is horizontal

Hue is the color of the soil (red, black) - On a Munsell chart Hue is the page itself and is represented by a color code 10YR (soil is yellow or red)

Question 16

What is a Pedon

Answer 16

A three-dimensional soil body depicting the range of characteristics of a given soil.

Question 17

What are the physical properties of soils and how do they affect plant growth?

Answer 17

The physical properties of soils are the depth, texture, structure, porosity, consistency

These have a direct effect on plant growth due to the physical makeup of the soil and soil horizons

Question 18

What are the narrower classifications of sand particles? what are their sizes?

Answer 18

Very Coarse Sand (2.0-1.0 mm)

Coarse Sand (1.0-0.5 mm)

Medium Sand (0.5-0.25mm)

Fine Sand (0.25-0.10mm)

Very fine sand (0.10-0.05mm)

Question 19

what is aggregate stability

Answer 19

Aggregate stability is the ability of soil aggregates to resist rearrangement by various forces that may impact the especially the effects of water

Question 20

Name and describe the 5 factors that determine soil formation

Answer 20

Parent Material
Climate
Living organisms
Topography
Time

Question 21

What are residual parent materials? (be able to give examples for exam)

Answer 21

Residual parent materials are common in upland areas that have not been covered by materials transported from elsewhere
Non transported residual parent materials include
Limestone
Sandstone
Shale
Basalt
Granite
Vegetation - Wet environments (Swamps, bogs)

Question 22

What are the types transported parent material? How were they transported?

Answer 22

Loess (silt) Dunes (sand) - transported by wind-aeolian

Salt: Marine (Coastal Plain), Still: Lacustrine (Glacial Lakebed) Moving: Alluvial (floodplain) - transported by water

Colluvial (slippage on slopes) - transported by gravity

Glacial till (unsorted) - Glacial Ice

Glacial Outwash (Sorted and Stratified) - Glacial Meltwater

Question 23

What are the four major soil forming processes and give a definition for each of them

Answer 23

Additions- additions of materials such as plant residues, dust, and salts, to the soil profile from outside sources
Creates the A horizon, forest or prairie

Translocations- translocation of organic and inorganic materials from one horizon up or down to another. Results in accumulations of materials in a particular horizon. - creates the E horizon and B horzin
Transformations- transformations such as rock weathering and organic matter decomposition that destroy some soils constituents and synthesize others

Losses- losses of materials such as water eroded particles oxidized organic matter and leached slats from the soil profile - leaching

Question 24

What are the master horizons and be able to characterize them

Answer 24

O- horizons Organic horizons that form above the mineral soil.

A - horizons Top most mineral horizons, darkened somewhat by organic matter accumulation. Some finer materials have moved downward

E horizons ones of maximum leaching (eluviation) of clay and of oxides of Fe and Al, generally lighter in color than A horizon.

B horizons - ones of accumulation (illuviation) of materials such assilicate clays and oxides of Fe and Al, and sulfates and carbonates of Ca, and Mg. Materials may have formed in place or may havem oved in from other horizons.
C horizons: Material underlying the A, E, and B horizons that is generally little affected by the processes that formed the horizons above it. It may or may not be the same as the material from which the upper horizon formed.

R layers: Underlying consolidated rock. Transition horizons:

Transitional horizons between master horizons, designated by using both capital letters, the dominant horizon being listed first (e.g. AE, EB, BE, and BC).

Question 25

What are the subordinate horizon designations? (MN only)

Answer 25

ss- slickensides
e- intermediately decomposed
t- accumulation of silicate clay
i - slightly decomposed organic matter
k- accumulation of carbonates
g- strong gleying
w-weakly developed
x fragipan
w- distinctive color or structure without clay accumulation

Question 26

What are the 5 parent materials found in MN?

Answer 26

Glacial till
outwash
Lacustrine Deposits
Alluvial Deposit
Residual Soils:

Question 27

What is a pedon

Answer 27

A three-dimensional soil body depicting the range of characteristics of a given soil.

Question 28

What is a Polypedon

Answer 28

A polypedon, or individual soil, is a group of closely related pedons that conceptually approximates what in the United States is called a soil series.

Question 29

How many moisture regimes are there?

Answer 29

There are five soil moisture regimes
Aquic
Udic
Ustic
Aridic
Xeric

Question 30

What are the 7 soil orders found in MN

Answer 30

Alfisols: Fertile soils with a clay-rich horizon, commonly found in forested and agricultural areas.

Entisols: Young soils with minimal development, often found in recently disturbed or newly deposited areas.

Inceptisols: Soils with weak horizon development, are found in various landscapes, including river valleys and hills.

Mollisols: Dark, fertile soils rich in organic matter, typically found in prairie regions and very important for agriculture.

Spodosols: Acidic soils with a leached layer, usually found under coniferous forests in sandy or coarse-textured areas.

Histosols: Organic soils high in decomposed plantmaterial, commonly found in wetland areas.

Vertisols: clay-rich soils that undergo significant vertical cracking during the dry seasons. Typically forming under grassland vegetation in basin or rolling hill landscapes

Question 31

What influences spatial variability among soils

Answer 31

Climate
Parent material
l Organisms
Topography Time