Unit 1, 2, 3 Flashcards
(146 cards)
1
Q
What is the pedogenic process?
A
process of soil genesis by the effects of environment (glaciers)
2
Q
What is parent material?
A
fragmented bedrock or superficial deposit
3
Q
What is eluviation?
A
Removal of materials. (think E for exit). downward process. (ex Ae)
4
Q
What is illuviation?
A
Deposition of materials from an upper horizon. (Ex Bt)
5
Q
What does the horizon suffix ‘h’ tell us?
A
humus (enrichment of organic matter)
6
Q
What does the horizon suffix ‘p’ tell us?
A
People. Disturbed by man, such as through cultivation, logging, and habitation
7
Q
What does the horizon suffix ‘m’ tell us?
A
Change in colour or structure, or both. Compared to C horizon.
8
Q
What soil structure does Bm horizon generally have?
A
Blocky or prismatic.
9
Q
What does the horizon name Bmk tell us?
A
has partial removal of carbonates
10
Q
What does the horizon suffix ‘k’ tell us?
A
Presence of primary carbonates. No visible white spots
11
Q
How large is a soil pedon control section?
A
1m wide x 1m depth
12
Q
What is leaching?
A
Removal of ions in solution (nutrients, salts dissolved in water) washed out below root zone
13
Q
What is soil enrichment?
A
addition of material to soil body, like the addition of organic matter.
14
Q
What is decalcification?
A
Acid reaction that removes carbonates from one or more horizons.
15
Q
What is calcification?
A
Deposition of carbonates transported down from an upper horizon. (ex Cca)
16
Q
What is salinization?
A
Accumulation of soluble salts. (ex Csa)
17
Q
Describe eolian PM
A
Deposited by wind. Medium to fine sand. Little to no clay. No coarse fragments.
18
Q
Describe glacial till PM.
A
Transported directly by glaciers. The glaciers tilled the land. Hummocky, rolling and undulating. Coarse fragments. LOAMY. Medium textured: loam, sandy clay loam, clay loam.
19
Q
Describe Glacio-Fluvial PM.
A
Transported by flowing glacial melt water. High sand content (loamy sand, sandy loam). LOTS of coarse fragments - drop stones. Gravel layers often in soil profile.
20
Q
Describe glacio-lacustrine.
A
Deposited by stagnant glacial melt water/lakes. Undulating, flat or level surface expression. Usually fills lows between hill tops. Clay, silty clay, sandy clay, clay loam, silty clay loam textural classes. Rarely coarse fragments are found.
21
Q
Describe colluvium PM.
A
deposited by gravity. Found at coulee bottoms or base of hills in mountainous areas. Unsorted PM.
22
Q
“landscapes characterized by non-linear round tops and depressions, random distribution of knolls and kettles. Slope gradients vary from 9%-70%”
A
Hummocky
23
Q
“landscapes characterized by wave-like pattern having moderate to strong slopes and gradients greater than 5%, slope is often 1.6km or greater”
A
Rolling
24
Q
What is the difference between “rolling” and “undulating” landscapes?
A
Rolling have moderate to strong slope gradients greater than 5%, whereas undulating are gentler slope gradientts between 2%-5%
25
What is the difference between "inclined" and "steep" landscapes?
Inclined slopes are 2%-70%. Steep are erosional slopes with gradients greater than 70%.
26
What is lithological discontinuity?
A clear, abrupt change in particle size distribution. NOT caused by pedogenic process.
27
Why is clay more fertile than sand?
The negative charge in clay attracts plant nutrients that have a positive charge. (Ex. Ca+ or Mg+)
28
What causes soils in the prairies to have an alkaline pH >7.5?
Natural presence of finely ground limestone. AKA free lime. Which has carbonates
29
What is the main source of free lime in prairie soil?
CaCO3. Calcium carbonate. (Also magnesium carbonate but in smaller amounts)
30
What is an advantage of soils formed in free lime rich PM?
Ca, and Mg fertilizers are hardly ever needed. Gives prairies an economic advantage.
31
What is a disadvantage of soils formed in free lime rich PM?
At this pH range, phosphate fertilizers react with Ca+ and become less available to plant uptake. And metal micronutrients also become less available to plant uptake.
32
Nitrogen is the only plant nutrient not provided by PM. How is nitrogen released for plant use?
Nitrogen is released when organic matter is decomposed. Plants use the nitrogen from the atmosphere NH4+ and NO3-
33
Increase in temperature causes the rate of soil formation to _______
increase
34
The prairie ecosystem includes which 4 soil zones?
Brown
Dark brown
Black
Dark gray
35
Define chernozemic.
Soil region in the Canadian prairies/ grasslands.
36
Define luvisolic.
Gray wooded soils in forested areas
37
Why do lower slopes have thicker profiles?
Receives soil material which has eroded from upper slopes.
38
What is lithological discontinuity caused by?
Depositional processes. Wind or water erosion. Illuviation or eluviation.
39
When reading the Munsell soil colour chart remember the acronym HVAC, which refers to?
Hue
Value
Chroma
(ex. 10YR 5/2)
40
What is the typical grassland soil hue as used in the munsell soil charts?
10YR
41
Gley hues are used to describe which kinds of soils?
Waterlogged
42
Define peds
structural unit of soil
43
Which kind of horizon is a platy soil structure commonly found?
Occurs naturally in eluviated horizons. (ex. Ae)
44
Which horizon is granular soil structure commonly found?
Surface horizons with high organic matter. (ex. Ah)
45
Describe blocky soil structure.
cube like. found in B horizons under forest (ex. Bt horizon). May also be found in Ah horizons.
46
Describe columnar soil structure.
prism like with round or flat top. Found in B horizons high in sodium (Na) content. (ex. Bn or Bnt horizon)
47
What does the suffix 'n' tell us?
high in sodium content
48
Describe prismatic soil structure.
Prism like with a spike like top. Typical of B horizons of grassland soils. (Ex. Bm horizon)
49
How does granular differ from structureless?
Granular is spheroidal structural units, referred to as crumb like. Like the aggregates when you turn sod over.
Structureless is single grain, like a sandy beach.
50
How is soil consistence described when wet?
Sticky/non sticky. Plastic
51
What does plasticity refer to?
Ability of soil to form a ribbon when wet.
52
What terms are used to describe soil consistence when moist.
Loose, friable, firm
53
What does friable mean?
Soil mass crushes easily
54
What terms are used to describe soil consistence when dry?
loose, soft, hard, very hard, extremely hard
55
How do the suffixes 'ca' and 'k' differ?
Both have carbonates.
ca has secondary carbonates(coatings): VISIBLE SPOTS.
k has primary carbonates. NOT VISIBLE SPOTS.
56
What is a horizon boundary?
The area between two adjacent horizons
57
What factor has the greatest impact on colour of A horizon?
organic matter
58
What soil structure is typical of compacted soil zones?
platy
59
How much organic matter does a horizon need to have to be considered an organic horizon?
17% organic C. 30% organic matter by weight
60
What is the main factor causing soil variability in the prairies?
the type of parent material the soil developed from
61
What is the oven dry weight of an acre-furrow slice?
2,000,000 lbs/ac.
62
What type of soil sampling is using in surveying?
Horizon depth sampling
63
What is horizon depth sampling?
One separate sample is obtained from each distinct horizon. Dig a survey style pit first (30cm diameter x 50cm deep). Continue sampling with a Dutch auger to depth of 1m from soil surface.
64
What is fixed depth sampling?
Recommended sampling depth intervals are
0-15cm, 15-30cm, 30-60cm.
Used in agriculture
65
What is fixed depth sampling commonly used for?
Agriculture for fertilizer recommendations and for assessing contamination.
66
Why are nitrate and sulfate recommended at 3 interval depths?
Because they are mobile; very soluble in water and move easily with soil water
67
What depth are potassium and phosphorus tested at? Why?
0-15cm. Because they are relatively immobile
68
What is a composite sample?
Combine several subsamples mixing them thoroughly into one sample and taking 500g to send for lab analysis
69
How to prevent cross contamination with soil samples?
Start by collecting control sample
When using an auger use a clean sharp knife to cut off the inside portion
Clean core and auger samplers between uses
70
Shallow top soil
Lower som
Higher erosion
Higher pH
Lower salinity risk
Lower fertility.
Is this characteristic of upper or lower slope
Knoll/upper-slope
71
What does summerfallow mean?
The practice of not planting a crop during growing season
72
What is 'subsoil' defined as?
lower part of the active soil, often B plus upper part of C. Less active than top soil but plant roots still have access to water and some nutrients
73
What is 'topsoil' defined as?
often A horizon. Enriched with organic matter. most fertile soil zone
74
What is solum?
A & B horizons
75
What is parent material?
superficial deposit / bedrock. Relatively thick. Range from 1m to 30m in Lethbridge area.
76
What is a horizon?
distant layers in a vertical section of soil
77
What are the main properties used to differentiate soil horizons?
colour, structure, texture, consistence and presence of carbonates
78
What is the main way you can tell you are in the C horizon?
no structural development
79
O, L, F, H are classified as which type of horizons?
organic, composed mainly of organic material
80
What does loam mean?
nearly equal parts sand silt and clay
81
Granular soil structure is consistent with which horizon?
Ah - horizons high in organic matter
82
What is the typical horizon sequence ID for the Lethbridge area?
Ah, Bm, Ck
83
What does the horizon suffix m tell us?
altered by oxidation, removal of carbonates
84
What are the major characteristics of L-F-H horizons?
8cm depth. very dark brown, black, partially decomposed leaf and grass litter. fibrous, fine and medium roots.
85
black, dark grayish. sandy clay loam; moderate medium to coarse. friable. wavy boundary
Ah horizon
86
Which area around Lethbridge is most susceptible to wind erosion? why?
Taber due to the sandy soils and low precipitation
87
Which horizon is related to eluviation?
Ae (e - exit)
88
Which horizon is related to illuviation?
Bt (texture)
89
What are the 5 pedogenic factors (factors of soil formation directly affected by PM)
texture
pH
fertility
salinity
topography
90
What is the difference between residual vs transported mineral PM?
residual PM is found in unglaciated areas (ex cypress hills)
Transported PM is a result of glaciers
91
What is soil salinity?
PM high in soluble salts
92
What is the direct cause of soil salinity in the prairies?
marine shale
93
Advantages of free lime rich soil?
Ca and Mg fertilizers are rarely needed
Ca binds to OM & clay which helps with structure creation
94
Which cation is best at forming aggregates?
Ca++
95
Disadvantages of free lime rich soil?
high pH. Phosphate fertilizers react with Ca and become less available to plant uptake. Metal micronutrients also become less available to plants.
96
What is free-lime defined as?
CaCO3. lime that can easily be broken apart. ex. Ca + CO
97
Can soils form in the absence of biotic activity?
no
98
What are the two major components of climate?
temperature
precipitation
99
What property of clay particles causes an increased risk of compaction?
platelike shape
100
What cation is most likely to cause clay dispersion?
Na++
101
What is chernozemic soil?
brown grassland soil
102
What is luvisolic soil?
gray wooded forested soil
103
Would vegetation grow better on a SW facing slope or NE?
NE, because it gets more shade
104
What is one of the most important properties that comes from PM?
soil texture
105
Which soil composition is best for plant growth?
44% mineral, 6% OM, 25% water, 25% air
106
Which type of soil causes a hard crust at soil surface?
high clay content and low OM content
107
What is the most significant effect of suspension-type wind erosion?
removes clay and SOM reducing soil fertility
108
What type of erosion is greater on soils with level topography?
wind erosion
109
What is the difference between nutrient adsorption and nutrient absorption?
absorption is when ions dissolved in water are taken into plant roots
adsorption is when ions are attached to surface of charged particles
110
What is nutrient adsorption?
when nutrients are attracted to surface of clay in a way they become loosely held to these particles.
111
Which soil zone is most at risk for erosion?
brown
112
Which agricultural management method has been crucial in reducing wind erosion?
adopting no till
113
What is the main factor that affects clod size?
soil texture
114
Which process is responsible for most wind erosion?
saltation. accounts for 50-90% of wind erosion.
115
What is negative erosion?
removal of soil or rock by wind or water
116
What is positive erosion?
deposition in another place
117
What is accelerated erosion?
due to human activity. can be 10,000 times as destructive as geological (natural) erosion
118
What are the 3 types of wind erosion?
creep, saltation, suspension
119
What is "creep" erosion?
rolling of aggregates of about 1mm. coarse sand. fills in furrows, resulting in a level surface. accounts for 5-25% of wind erosion.
120
What is 'saltation' erosion?
medium to fine sand aggregates 'jump' and break up larger particles moving more aggregates
121
What is 'suspension' erosion?
moves soil particles less than 1mm. results in dust clouds. greatly affects soil fertility. can move soil hundreds of km. accounts for 15% of wind erosion
122
Which type of wind erosion affects soil fertility?
suspension
123
Which texture of soil have the greatest risk for wind erosion on the prairies?
coarse textured soils. sand, sandy loam, loamy sand
124
What is the effect of SOM on increasing soils resistance to wind erosion?
it helps forming and keeping aggregates together
125
What is fine earth fraction vs coarse fragments?
fine earth fraction is sand silt and clay <2mm
coarse fragments are boulders stones cobbles and gravel
126
As particle size decreases, specific surface area _______?
increases
127
A handful of clay has what surface area?
5 acres
128
A handful of sand has what surface area?
1 acrea
129
Why do clay particles behave like colloids?
because of their extremely small size
130
What is a plow pan?
Hard compacted area just below soil surface
131
What property does a penetrometer measure that is also an indicator of soil compaction?
Soil strength
132
When using a penetrometer what does a reading of > 300 psi mean?
Too compacted for root growth
133
Methods for plow pan correction?
Subsoiling - ripping
Tillage radish
Moldboard - old technique that digs up and turns soil over. Not used much anymore
134
Which varies more bulk density or particle density?
Bulk density
135
Which horizon / suffix is used for the presence of secondary carbonates?
Cca
White spots are visible
136
What horizon is is used when there are primary carbonates (non visible)?
Ck
137
Which soil structure is associated with soil high in sodium?
Columnar
138
What soil structure is associated with eluviated horizons?
Platy (Ae)
139
What is a representative soil sample?
One taken following proper procedures
140
What is a control sample?
Non contaminated sample
141
What is the expected depth of tillage?
6 inches
142
Which nutrients are already found in western Canadian soils due to free lime rich parent material?
Ca and Mg
143
What is a moldboard?
Curved iron plates attached to tractor
144
What should soil moisture be when using a penetrometer?
100% capacity
145
What is clay dispersion?
Caused by sodium. Clay particles separated from each other
146
What are clods?
Management induced aggregates
