Soils Flashcards
(129 cards)
1
Q
What are the two levels of the BEC system?
What does BEC stand for?
A
*Zonal Level - Macro Climatic Conditions
*Site Level - Soil Nutrient and Moisture Status
BEC = Bioecological Classification System
2
Q
What are some of Soils Vales?
A
- Medium for Plant growth
- Plants absorb critical source of nutrients
- Serves as a habitat for millions of organisms (critical to O.M. Decomposition)
- Recycling centre for nutrients from O.M
- Serves as a water filtration and storage system
- Serves as a source of materials for road construction and other buildings needs
3
Q
Why study Soils in Forestry?
A
- Understand soil make-up and functions helps appreciate site’s tree growing potential and yield.
- Understand it’s capability to deal with abuse and its resilience to harvesting and manipulations through harvesting and other silviculture treatments
4
Q
What is all soil composed of?
A
OOMWA
- Organic Matter
- Organisms
- Mineral Matter
- Water
- Air (Pore Space)
5
Q
Define; Soil
A
The unconsolidated layer of material that sits on the surface of the earth and serves as a medium for plant growth
6
Q
Define; Solum
A
The differentiated upper portion of the soil (The A& B Horizons)
-The material from which solum develops is referred to as “parent material”
7
Q
Define; Organic Soil
A
Contains more than 17% Organic Carbon
30% O.M
8
Q
Define; Mineral Soil
A
Contains less than 17% Organic Carbon
9
Q
Define; Parent Material
A
The unconsolidated material from which solum develops
- often associated with the C horizon or the undifferentiated portion of a soil profile
- -The material from which solum develops is referred to as “parent material”
10
Q
Define; Pedon
A
The smallest 3 dimensional unit of soil that can be used to describe the soil
11
Q
What are agents of transporting soil
A
W-WIGO
- Water - Running rivers and Streams, Lakes, Wetlands
- Wind
- Ice (Continental/Mountain Glaciers)
- Gravity
- Ocean Currents
12
Q
What does a soil profile with a ‘Ae’ horizon (white in colour) and an ‘Bhf’ horizon (deep brown/red in colour) tell you about the soil?
A
The nutrients (Red = Iron and Aluminum) translocate (Eluviated) down from the A horizon to the B horizon.
13
Q
How was most the soil derived in BC and Canada?
A
Most of the soil is Glacially derived, meaning;
glaciers receded the material that was left behind is the source of our soil
14
Q
Define; Basal Till
A
Normally there are 2 separate layers of “residual” material, the lower layer (stuff next to the rock) is quite compacted and does not weather very easily or quickly, it is Basal Till
15
Q
Define; Ablation Till
A
The material that sits on top of the basal till is referred to as the ‘Ablation: till and is quite loose and easily weathered (broken down into smaller pieces)
*The material that was incorporated into the ice, not the stuff below the ice.
16
Q
What can change Solum?
A
- Climate
- Organic Matter (O.M)
- Soil Organisms
- Topography
- Time
17
Q
Which direction does solum develop?
A
From the Top Donwards
18
Q
Define; “O” horizon
A
Organic Horizon (in forest environment this layer is referred to as the LFH layer)
19
Q
Define; ‘LFH’ Layer
A
Litter, Fermentation and Humus - The Forest Floor
-Strictly Organic Material
20
Q
Define; Regosol
A
When development of solum starts, the first soil type that you have is a regosol, it is very poorly developed immature soils
21
Q
Define; Brunisol
A
Develop under relatively dry to moist warm environment. In Canadian forest, common in Nanaimo.
Ah
Bm
C
22
Q
Define; Podzols
A
Develop under cool/cold and moist to wet environment. Normally develop from coarse texture parent materials w/ high sand content. Common at higher elevations)
Ae
Bhf/Bfh
C
23
Q
Define; Luvisols
A
Develop under cool/cold and moist to wet environment. Normally develop from fine texture parent materials w/ high clay content. Common to the centeral interior forests Ah Ae Bt C
24
Q
Define; Chenozems
A
Develop in dry and warm environment such as grasslands
Ah
Bm
C
25
What the two portions mineral matter is broken down into?
- Coarse fragment - Material larger than 2.0mm
- -Gravel 2.00mm - 7.5cm
- -Cobbles 7.5cm - 25cm
- -Stones everything > 25cm
- Fine material - Matierl smaller than 2.0mm
- -Sand = 2.0mm - 0.05mm
- -Silt = 0.05mm - 0.002mm
- -Clay = anything smaller than 0.002mm
26
What does Colloidal fraction mean?
Material that is less than 1 micron (1X10-6m)
Example: Humus
*Source of most nutrients
27
Define; Ah
A humus enriched mineral soil horizon.
| Always found on the top portion of mineral layer below forest floor
28
Define; Ae
A mineral soil horizon that has lost its Clay and Humus matter (Eluviated)
Ae horizons only found below an Ah horizon
29
Define; Bm
C horizons that have been moderately modified (weathered) that results in a light to dark brown colour
30
Define; Bt
C or Bm Horizons that have been enriched w/ clay eluviated from the Ae.
They are characteristically shiny or glassed/glossy look because of addition of clay.
31
Define; Bf or Bhf or Bfh
Horizons that have been enriched with iron, aluminium and organic colloids from the weathering of the minerals in the Ae Horizon
32
Define; Nutrients
Any element or compound contributing to an organism's metabolism, growth or other functioning
33
Define; Essential Nutrients
Nutrients that can not be synthesized by the organism and therefore must be obtained from an external source (soil)
34
What elements make up 99% of all the weight that makes up all living matter
What composes less than 1% of living matter weight
CHONPS
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Phosphorus
- Sulphur
1% = Cationic nutrients such as Potassium (K+) Magnesium (Mg+2) and Calcium (Ca+2)
35
What are the 3 sources of nutrients?
PST
- Primary (Air and Rocks)
- Secondary (O.M)
- Tertiary (Internal Cycling)
36
What is the average amount of essential inorganic nutrients trees require for their growth, development and reproduction?
~16-18
37
Define; What Macronutrients include
Hydrogen, Carbon, Oxygen, and Nitrogen
*All from from the Atmosphere (Air, Water and Ammonium)
Phosphorus, Potassium, Calcium, Magnesium, and Sulphur
*All from from soil (rock forming minerals)
38
Define; What Micronutrients include
Chlorine, Boron, Iron, Manganese. Zinc, Copper, Nickel, Molybdenum
39
What are some Rock Forming Minerals that come from the weathering of Silicate?
* Feldspars -Orthoclase and Plagioclase (Abite and Anorthite)
* Muscovite
* Biotite
* Pyroxines
* Hornblende
* Olivine
40
Define; Texture
Texture is determined by the Relative Proportion of Sand, Silt and Clay found within the soil.
*It refers to the size of the individual soil particles and has nothing to do with the amount of O.M present in the soil
41
Define; Sand
- 2.0mm - 0.05mm in size
- Grainy to touch
- Individual grains or particles can been seen with the naked eye.
- Largest of the 3 soil particle classes
- Sandy soils are Coarse in Texture
- in most cases, quartz (silicone dioxide-very strongly bonded together) *does not chemically break down but allows for good drainage and trafficability
42
Define; Silt
- 0.05mm - 0.002mm
- Feels Soapy. Also feels Smooth and Slippery to touch when Wet*
- Individual particles only seen with microscope
- Primarily produced by "glacial grinding" and mechanically weathered sand
- Some is produced through chemical weathering of silicates minerals such as feldspars
- Silt doesn't produce any nutrient value but clay particles stick to silt and it is those that supply nutrients
- Problems = Drainage problems, frost heaving in cold air drainage environments. Tend to plug or block soil pore spaces (due to spherical shape)
43
Define; Clay
- 0.002mm and smaller
- Sticky and Plastic-like to handle when Wet* Floury when dry
- Individual particles are extremely small, only seen w/ electron microscope.
- High clay content soil is very Fine in Texture
- Clay is the end product of the chemical weathering of rock forming minerals
44
Define; Loam
- Another soil texture classification class
- Loamy soil contains considerable amounts of sand, silt, and clay.
- Preferred texture for horticulture because of its ease of workability.
- Relatively well drained and produces a lot of nutrients
45
Define; Difference between Qualitative and Quantitative Examples of Soil
Qualitative: Using Adjectives to define something, doesn't include numeric values, it describes how the soil feels
Quantitative: Soil sample is brought into a lab and broken down (% of sand, silt, clay = 100%)
*Solution density using a hydrometer, Mechanical Sieving, Pipet Method
46
What differentiates material layers in soil?
- Additions - Material such as o.m from the 'o' horizon into the profile
- Losses - By wind/surface erosion, Leeching
- Transformations
- Translocation - Material moving through the soil, can move up or down the soil (ex. Temp draws moisture out) Example of translocation = a slope with finer textured material at the base and coarser material at the top because of translocation!)
47
Define; Illuviated
An 'A' layer or top mineral horizon (below the humus or forest floor) is enriched with o.m (Ex.Ah)
48
Define; Eluviated
The 'A' layer or top mineral horizon (below the humus or forest floor) was enriched with o.m and clay and it has been leached out of this layer causing the layer to be a Ae layer
49
Define; 'B' Horizon
- Differentiated "C" material (Parent Material) and lies between the "A" and the "C" Horizons
- Can be significantly or moderately modified and usually has been enriched w/ materials from above (usually o.m and clay)
50
Define; "C" Horizon
The undifferentiated Parent Material
51
What are the two ways Horizon boundaries are differentiated?
* Distinctiveness
- Abrupt (15cm)
* Form
- Smooth, Wavy, Irregular, Broken
52
Define; Particle Density (D(sm)P) (g/cm3)
Defines the mass of a unit of volume of oven dry soil, pore space EXCLUDED
-sandy soils tend to have higher DP than fine textured soils because of their high silicate RFM content that are high in iron and other metals
53
Define; Bulk Density? (D(sm)b)(g/cm3)
Defines the mass of a unit volume of soil, Pore Space INCLUDED
-Sandy soils usually have a high Db but have low Pore Space. Fine Textured clay and/or silty soils, however, tend to have a low Db but have a high Pore Space due to the development of "peds" or secondary particles with internal pore space
54
What is the Equation used to discover Bulk Density of soil?
Bulk Density = Weight of Oven Dry Soil / Total Volume of Soil (Solids + Pores)
55
What is the Equation used to discover Solid Particle Density of Soil?
Solid Particle Density = Oven dry soil mass(g) / Volume of Soil particles (cm3)
56
What is Pore Space critical to?
A-D-R
- Aeration
- Drainage
- Root Growth and Development
57
Which has higher Soil Porosity;
| Fine Textured soils or Coarse Textured soils?
Fine Textured Soils tend to have higher soil Porosity
58
What additions are added to develop soil structure?
OOSA
- Organic Matter
- Supplemental Clays
- Oxides of Iron and Aluminium
- And other Cementing agents such as Salts
* Expansion and Contraction of high clay soils as a result of wetting/drying also contributes to structure development
59
What are 'Peds?'
```
Peds are secondary soil structures made up of primary soil particles;
Sand, Silt and Clay
Including binding agents such as;
-Organic Matter
-Salts
-Oxides
```
60
Define; Granular
A soil Structure Classification common in the Upper soil profile where Organic Matter accumulates
61
Define; Prismatic
A soil Structure Classification common in Clay soils that experience annual wetting and drying
62
Define; Blocky
A soil Structure Classification common in Coarse textured sandy soils that have been cemented with oxides of Iron and Aluminium
63
Define; Platy
A soil Structure Classification common in Compacted soils such as Local Basal tills
64
Define; Single Grains
A soil Structure Classification common in Sandy Soils that have been recently developed from beach deposits
65
Define; Massive
A soil Structure Classification about soil that has no visible structure, is hard to break apart and appears in very large clods
66
Define; Columnar
A soil Structure Classification of soil that develops in dry environments where a great deal of evapotranspiration occurs such as in the Bunch Grass BGCZ in Southern Interior of BC around alkali lakes. The columns are capped with salt
67
What does Soil Structure tell us?
Suggests conditions of development and/or states of the environment
68
What can Soil Colour tell you about soil?
- How well the soil allows gases and water to flow
- The extent of chemical weathering that goes on
- The soils overall productivity
- Describe many soil chemical/mechanical processes
- -Oxidation/Reduction, Poor Aeration, additions and losses
69
What are some factors that change Soil Colour?
- P-PAE
- Parent Material Type
- Percent of Organic Matter Content
- Amount of Eluviation and/or illuviation that has occurred
- Extent of Oxidation and/or Reduction that has taken place, and the amount of Oxides accumulation in the soil
70
What does the colour Red tell you about the soil?
- Presence of ferrous compounds Fe++
- It is well aerated
- Lots of Organic Humus
- Cheliation - process of moving organic material, iron and aluminum oxides down from A horizon to B. Ligans (Organic Humus Compounds) attaches with Iron and Al and translocates down to B horizon where they detach (producing Cheliates) - Enhance amount of O.material (humus) in the soil
71
What does the colour Yellow tell you about the soil?
Intermediate Aeration
72
What does the colour Blue and Grey tell you about the soil?
-Poor Aeration
-Presence of Ferric Compounds Fe+++
(Fe+++ produced by bacterial respiration in Anaerobic Enviornments
73
What is Oxidation?
Loss of Electron
74
What is Reduction?
Gain of Electron
75
What are Mottles?
Spots of Blotches that are different from the background colour - they are usually red to orange and result from reducing conditions - poor aeration usually due to flooding or saturated conditions
-Blotchy Colour Conidtion
76
What is used to ensure that colour definition is consistent?
The Munsell Colour Notation
-Broke down colour into 3 parameters;
Hue, Value and Chroma
77
Define; Hues
The 5 dominant colours with 5 additional "half-way" colours such as yellow-red.
The Dominant Spectral Colour
78
Define; Value
Describes the Brightness of the colour from Black (0) to White (10) and 5 being neutral Grey
79
Define; Chroma
Measures of Purity or Strength of the colour on a scale from 0 (weak) to 12 (Very strong)
-Although the later only applies to some colours
80
What is the order (hue,chroma, and value) of a colour code
Hue -> Value -> Chroma
81
What are mottles defined in terms of?
- Abundance
- Size
- Colour
- Colour contrast to the matrix
82
What is Gleying?
- Extreme Case of Mottling!
- Result of Reduction by Anaerobic Bacterium
- Bacterium carry out electron transfer respiration - they use electrons from ferrous iron for energy and create ferric iron in the process resulting in a blue grey colour
83
What are Soil Physical Characteristics?
THC - PPDD'S
- Texture - including coarse fragment content
- Horizon Configuration
- Colour
- Porosity
- Plant Rooting Patterns
- Density - Particle and Bulk
- Drainage
- Structure and Consistency
84
Define; Soil Texture
Refers to the relative amount of sand, silt, clay in the soil. Each as a % of the total volume
*Refers to only the mineral fraction and does not include the organic fraction
85
What are most rocks composed of?
Rock Forming Minerals
- the most common are the silicates such as hornblendes, quartz, micas, and feldspars.
* When these are chemically weathered, nutrients such as phosphorus, potassium, and calcium are released from the molecule to the soil
86
What is left when a RFM is completely weathered?
The residual end product is either a silicon tetrahedron or an aluminum octahedron.
-These join together to form clay sheets that carry a net negative charge to which nutrients and other molecules adhere and are stored where they can be picked up by plants
87
What is Clays function in soil?
It stores nutrients and carries nutrients throughout the soil because of the clays structure with negative outter shells
88
What is an ion?
A molecule with an negative or positive charge
89
What can cause "long term reduction in site productivity"
- Use of inappropriate harvesting methods o sensitive sites = Soil Compaction, Puddling, Erosion (Wind), and Forest Floor Displacement
- Reforestation with wrong species
- Significantly changing the micro environment of a site by aggressive harvesting
90
What is Site Degradation?
The long term reduction of site productivity. Can be caused by abusing the soil and also caused by planting the wrong species
91
What is Soil Compaction?
The reduction of soil pore space and the increase of soil bulk density or mass.
Common in soils with high silt and clay content and can occur regardless of soil moisture content
*Result is a reduction in:
-Water Percolation through the soil
-Air movement through the soil
-Root penetration ability and therefore growing space
92
What is Soil Puddling?
- Worst type of site degradation
- Combination of Compaction and re-orientation of the clay fraction to a horizontal plane resulting in significantly reduced water infiltration capacity and increased bulk density.
- Common in wet, high clay content soils
93
What are CFC's values and shortfalls?
- CFC's are a long term nutrient source
- High CFC can withstand physical abuse
- High CFC tends to drain more easily
- High CFC are more difficult to plant in
94
Why is it important to recognize parent material?
For what they can offer as it is important to recognize the productive capacity of a soil
95
What does 'in-situ' mean?
Weathering of bedrock producing "residual or saprolitic" soils from which solum develop
96
Where is rock produced?
Rock is produced from the re-cycling of Material (mostly rock) within the Lithosphere - the upper mantel and crust
97
How can you identify the parent material types?
By Characteristics such as;
- Presence or absence of Coarse Fragments
- Shape of its Coarse Fragments
- Whether the CFC is Stratified or Homogenous
- Texture of the soil
* And their macro surficial characteristics
- the landscape type such as flat, sloped, undulating and broken
98
How are Materials transported or deposited by or in water?
| And other Forces?
- Rivers and Streams = Fluvial (Alluvium)
- Lakes = Lacustrine
- Oceans = Marine
- Ice (Glaciers) = tills; ^outwash, lacustrine, fluvial, marine
* Wind = Eolian (Loess)
* Gravity = Colluvium
* In-Situ Weathered Bedrock = Saprolitic
99
Define; Colluvial
-Material is coarse, angular, and somewhat stratified.
-Most cases, the slope of this type of deposit is ~80% - the natural angle of repose
Ex. The Hope Slide
100
Define; Colluvium
- Generally considered unstable and harvesting and road building should be limited or carefully planed.
- Well drained, productivity varies depending on the moisture received and the texture of the soil
101
Define; Fluvial (Alluvium)
- Produced from flowing water in rivers
- Generally composed of coarse gravels, cobbles, stones, and sand and is sorted or stratified
- Terrain is generally flat
- Deposits are generally found near to or adjacent to streams and rivers
- Site is pore usually because of low % of clay, and ability to retain moisture and organic colloids
* Great sites for road building, high trafficability potential
102
Define; Glacial Fluvial
- Generally found at higher elevations
| - Tend to be much coarser than post glacial fluvial and not as well stratified
103
Define; Basal Tills
- Very common in mountainous country
- Left behind by moving glaciers and are very strongly compacted
- Texture of most tills on island = loamy to sandy loam with a relatively high CF that are homogeneously distributed across the profile
- Solid P.M on which to build and generally dont cause road stability problems
104
Define; Glacio-Marine
- Unique deposits generally found near coastal areas produced by "calving" ice melt
- Generally fine textured with some homogeneously distributed CF
105
Define; Glacio-luacustine
- Formed during glacial wasting behind ice dams that form in river valleys
- Paired terraces are created by the "dam" breaking
106
Define; Loess or Eolian
-Wind blown deposits of fine sands and silts (
107
Define; Saprolites or Residual
-"On-site" weathered materials, including bedrock, are found in many parts of the world - mostly in areas that have not been glaciated in recent geological history
108
Define; Volcanics
- Deep deposits of ash and debris on the landscape from which solum has developed
- Material is quite coarse and often stratified from repeated eruptions
- Solum profile is poorly developed - due to their relative youth
109
Why do Clays have such a high specific surface area?
Clay particles or microcells create multitudes or interior surfaces (Sheets connected to sheets) and contributes to very large specific surface area.
110
What is the equation used to determine the % Porosity of a soil sample?
% Porosity = Volume of soil Pores (cm3) / Total Volume of the soil (cm3)
*100 - (Db/Dp X 100)
111
Which soil textural fraction will settle most rapidly to the bottom of a lake?
Sand is distributed throughout the creeks and rivers before it gets to the lake. The silt is heavier than clay. Then silts then clays
112
Which soil textural fraction contributes most to water turbidity?
Clay
113
What is the difference between Soil consistence and consistency?
More or less the same thing. Consistence is a term used by pedologists, while soil engineers prefer the term consistency
114
Define; Consistence/Consistency
The degree of resistance to deformation or rupture exhibited by a soil when subjected to externally applied mechanical stresses
* Manifestation of the combined forces of adhesion and cohesion between soil particles that contribute to;
1. The attraction between soil particles and pore water
2. The attraction of soil particles to one another
115
What influences Consistence/Consistencey
POCSSS
- Particle size distribution
- Organic Matter Content
- Clay Mineralogy (Types of clay and their properties)
- Soil Solution Chemistry (Adsorbed cations)
- Soil Structure
- Sample Pretreatment - how the soil is handled
116
Who is Atterberg and what is he known for?
-Swedish Scientist proposed series of tests for defining the properties of cohesive soils
-Strength Decreases as Water Content Increases
*There are 4 basic states for soil:
Solid, Semisolid, Plastic, and Liquid
117
Define Liquid Limit (LL)
The moisture content at which soil begins to behave as a liquid material and begins to flow
118
Define Shrinkage Limit (SL)
The moisture content at which no further volume change occurs with further reduction in moisture content
119
Define Plastic Limit (PL)
The moisture content at which soil begins
120
Define Soil Plasticity Index
The Plasticity index (PI) is the difference between the liquid limit and the plastic limit of a soil
PI = LL - PL
121
How is a Qualitative Rating used in classifying soil
```
Very Soft
Soft
Stiff
Very Stiff
Hard
*Determined by discovering the soil's resistance to penetration by a blunt object
```
122
Define Chesion
The attraction of one water molecule to another resulting from hydrogen bonding
123
Define; Adehsion
The attractive forces of the water molecules to non-water molecules such as soil particles
124
Define Newton (N)
The Force required to accelerate a mass of one kilogram at a rate of one meter per second square
125
What does soil structure describe?
The arrangement of the solid parts of the soil and of the pore space located between them, the aggregation of soil primary particles
126
What is Soil Structure Dependent on?
- Parent Material Type
- Environmental conditions under which the soil formed - local climate
- The amount and Type of Clay present
- The Organic Materials present
- The recent history of management of the site and soil
127
What is the classification of soil structure based on?
Grade, Form, and Size Particles
Grade; Structureless, Weak, Moderate, Strong
Form; Granular, Platy, Columnar
Size; Very Fine, Fine, Medium, Coarse, Very Coarse
128
What is a Solonetzic Soil?
Develop in very arid environments where (Na, K, Mg) salts accumulate in the surface horizons resulting in the development of pronounced "prismatic" structure
129
What is a Vertisol Soil?
Develop in soils with a high smectite clay content that has a very high swell-shrink potential creating strong wedged "columnar" structure
