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Soils > Unit 1, 2, 3 > Flashcards

Unit 1, 2, 3 Flashcards

1
Q

What is the pedogenic process?

A

process of soil genesis by the effects of environment (glaciers)

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2
Q

What is parent material?

A

fragmented bedrock or superficial deposit

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3
Q

What is eluviation?

A

Removal of materials. (think E for exit). downward process. (ex Ae)

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4
Q

What is illuviation?

A

Deposition of materials from an upper horizon. (Ex Bt)

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5
Q

What does the horizon suffix ‘h’ tell us?

A

humus (enrichment of organic matter)

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6
Q

What does the horizon suffix ‘p’ tell us?

A

People. Disturbed by man, such as through cultivation, logging, and habitation

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7
Q

What does the horizon suffix ‘m’ tell us?

A

Change in colour or structure, or both. Compared to C horizon.

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8
Q

What soil structure does Bm horizon generally have?

A

Blocky or prismatic.

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9
Q

What does the horizon name Bmk tell us?

A

has partial removal of carbonates

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10
Q

What does the horizon suffix ‘k’ tell us?

A

Presence of primary carbonates. No visible white spots

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11
Q

How large is a soil pedon control section?

A

1m wide x 1m depth

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12
Q

What is leaching?

A

Removal of ions in solution (nutrients, salts dissolved in water) washed out below root zone

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13
Q

What is soil enrichment?

A

addition of material to soil body, like the addition of organic matter.

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14
Q

What is decalcification?

A

Acid reaction that removes carbonates from one or more horizons.

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15
Q

What is calcification?

A

Deposition of carbonates transported down from an upper horizon. (ex Cca)

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16
Q

What is salinization?

A

Accumulation of soluble salts. (ex Csa)

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17
Q

Describe eolian PM

A

Deposited by wind. Medium to fine sand. Little to no clay. No coarse fragments.

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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.

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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.

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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.

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21
Q

Describe colluvium PM.

A

deposited by gravity. Found at coulee bottoms or base of hills in mountainous areas. Unsorted PM.

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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

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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

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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%

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25
Q

What is the difference between “inclined” and “steep” landscapes?

A

Inclined slopes are 2%-70%. Steep are erosional slopes with gradients greater than 70%.

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26
Q

What is lithological discontinuity?

A

A clear, abrupt change in particle size distribution. NOT caused by pedogenic process.

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27
Q

Why is clay more fertile than sand?

A

The negative charge in clay attracts plant nutrients that have a positive charge. (Ex. Ca+ or Mg+)

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28
Q

What causes soils in the prairies to have an alkaline pH >7.5?

A

Natural presence of finely ground limestone. AKA free lime. Which has carbonates

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29
Q

What is the main source of free lime in prairie soil?

A

CaCO3. Calcium carbonate. (Also magnesium carbonate but in smaller amounts)

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30
Q

What is an advantage of soils formed in free lime rich PM?

A

Ca, and Mg fertilizers are hardly ever needed. Gives prairies an economic advantage.

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31
Q

What is a disadvantage of soils formed in free lime rich PM?

A

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.

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32
Q

Nitrogen is the only plant nutrient not provided by PM. How is nitrogen released for plant use?

A

Nitrogen is released when organic matter is decomposed. Plants use the nitrogen from the atmosphere NH4+ and NO3-

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33
Q

Increase in temperature causes the rate of soil formation to _______

A

increase

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34
Q

The prairie ecosystem includes which 4 soil zones?

A

Brown
Dark brown
Black
Dark gray

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35
Q

Define chernozemic.

A

Soil region in the Canadian prairies/ grasslands.

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36
Q

Define luvisolic.

A

Gray wooded soils in forested areas

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37
Q

Why do lower slopes have thicker profiles?

A

Receives soil material which has eroded from upper slopes.

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38
Q

What is lithological discontinuity caused by?

A

Depositional processes. Wind or water erosion. Illuviation or eluviation.

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39
Q

When reading the Munsell soil colour chart remember the acronym HVAC, which refers to?

A

Hue
Value
Chroma
(ex. 10YR 5/2)

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40
Q

What is the typical grassland soil hue as used in the munsell soil charts?

A

10YR

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41
Q

Gley hues are used to describe which kinds of soils?

A

Waterlogged

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42
Q

Define peds

A

structural unit of soil

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43
Q

Which kind of horizon is a platy soil structure commonly found?

A

Occurs naturally in eluviated horizons. (ex. Ae)

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44
Q

Which horizon is granular soil structure commonly found?

A

Surface horizons with high organic matter. (ex. Ah)

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45
Q

Describe blocky soil structure.

A

cube like. found in B horizons under forest (ex. Bt horizon). May also be found in Ah horizons.

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46
Q

Describe columnar soil structure.

A

prism like with round or flat top. Found in B horizons high in sodium (Na) content. (ex. Bn or Bnt horizon)

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47
Q

What does the suffix ‘n’ tell us?

A

high in sodium content

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48
Q

Describe prismatic soil structure.

A

Prism like with a spike like top. Typical of B horizons of grassland soils. (Ex. Bm horizon)

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49
Q

How does granular differ from structureless?

A

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.

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50
Q

How is soil consistence described when wet?

A

Sticky/non sticky. Plastic

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51
Q

What does plasticity refer to?

A

Ability of soil to form a ribbon when wet.

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52
Q

What terms are used to describe soil consistence when moist.

A

Loose, friable, firm

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53
Q

What does friable mean?

A

Soil mass crushes easily

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54
Q

What terms are used to describe soil consistence when dry?

A

loose, soft, hard, very hard, extremely hard

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55
Q

How do the suffixes ‘ca’ and ‘k’ differ?

A

Both have carbonates.
ca has secondary carbonates(coatings): VISIBLE SPOTS.
k has primary carbonates. NOT VISIBLE SPOTS.

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56
Q

What is a horizon boundary?

A

The area between two adjacent horizons

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57
Q

What factor has the greatest impact on colour of A horizon?

A

organic matter

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58
Q

What soil structure is typical of compacted soil zones?

A

platy

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59
Q

How much organic matter does a horizon need to have to be considered an organic horizon?

A

17% organic C. 30% organic matter by weight

60
Q

What is the main factor causing soil variability in the prairies?

A

the type of parent material the soil developed from

61
Q

What is the oven dry weight of an acre-furrow slice?

A

2,000,000 lbs/ac.

62
Q

What type of soil sampling is using in surveying?

A

Horizon depth sampling

63
Q

What is horizon depth sampling?

A

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
Q

What is fixed depth sampling?

A

Recommended sampling depth intervals are
0-15cm, 15-30cm, 30-60cm.

Used in agriculture

65
Q

What is fixed depth sampling commonly used for?

A

Agriculture for fertilizer recommendations and for assessing contamination.

66
Q

Why are nitrate and sulfate recommended at 3 interval depths?

A

Because they are mobile; very soluble in water and move easily with soil water

67
Q

What depth are potassium and phosphorus tested at? Why?

A

0-15cm. Because they are relatively immobile

68
Q

What is a composite sample?

A

Combine several subsamples mixing them thoroughly into one sample and taking 500g to send for lab analysis

69
Q

How to prevent cross contamination with soil samples?

A

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
Q

Shallow top soil
Lower som
Higher erosion
Higher pH
Lower salinity risk
Lower fertility.

Is this characteristic of upper or lower slope

A

Knoll/upper-slope

71
Q

What does summerfallow mean?

A

The practice of not planting a crop during growing season

72
Q

What is ‘subsoil’ defined as?

A

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
Q

What is ‘topsoil’ defined as?

A

often A horizon. Enriched with organic matter. most fertile soil zone

74
Q

What is solum?

A

A & B horizons

75
Q

What is parent material?

A

superficial deposit / bedrock. Relatively thick. Range from 1m to 30m in Lethbridge area.

76
Q

What is a horizon?

A

distant layers in a vertical section of soil

77
Q

What are the main properties used to differentiate soil horizons?

A

colour, structure, texture, consistence and presence of carbonates

78
Q

What is the main way you can tell you are in the C horizon?

A

no structural development

79
Q

O, L, F, H are classified as which type of horizons?

A

organic, composed mainly of organic material

80
Q

What does loam mean?

A

nearly equal parts sand silt and clay

81
Q

Granular soil structure is consistent with which horizon?

A

Ah - horizons high in organic matter

82
Q

What is the typical horizon sequence ID for the Lethbridge area?

A

Ah, Bm, Ck

83
Q

What does the horizon suffix m tell us?

A

altered by oxidation, removal of carbonates

84
Q

What are the major characteristics of L-F-H horizons?

A

8cm depth. very dark brown, black, partially decomposed leaf and grass litter. fibrous, fine and medium roots.

85
Q

black, dark grayish. sandy clay loam; moderate medium to coarse. friable. wavy boundary

A

Ah horizon

86
Q

Which area around Lethbridge is most susceptible to wind erosion? why?

A

Taber due to the sandy soils and low precipitation

87
Q

Which horizon is related to eluviation?

A

Ae (e - exit)

88
Q

Which horizon is related to illuviation?

A

Bt (texture)

89
Q

What are the 5 pedogenic factors (factors of soil formation directly affected by PM)

A

texture
pH
fertility
salinity
topography

90
Q

What is the difference between residual vs transported mineral PM?

A

residual PM is found in unglaciated areas (ex cypress hills)
Transported PM is a result of glaciers

91
Q

What is soil salinity?

A

PM high in soluble salts

92
Q

What is the direct cause of soil salinity in the prairies?

A

marine shale

93
Q

Advantages of free lime rich soil?

A

Ca and Mg fertilizers are rarely needed
Ca binds to OM & clay which helps with structure creation

94
Q

Which cation is best at forming aggregates?

A

Ca++

95
Q

Disadvantages of free lime rich soil?

A

high pH. Phosphate fertilizers react with Ca and become less available to plant uptake. Metal micronutrients also become less available to plants.

96
Q

What is free-lime defined as?

A

CaCO3. lime that can easily be broken apart. ex. Ca + CO

97
Q

Can soils form in the absence of biotic activity?

A

no

98
Q

What are the two major components of climate?

A

temperature
precipitation

99
Q

What property of clay particles causes an increased risk of compaction?

A

platelike shape

100
Q

What cation is most likely to cause clay dispersion?

A

Na++

101
Q

What is chernozemic soil?

A

brown grassland soil

102
Q

What is luvisolic soil?

A

gray wooded forested soil

103
Q

Would vegetation grow better on a SW facing slope or NE?

A

NE, because it gets more shade

104
Q

What is one of the most important properties that comes from PM?

A

soil texture

105
Q

Which soil composition is best for plant growth?

A

44% mineral, 6% OM, 25% water, 25% air

106
Q

Which type of soil causes a hard crust at soil surface?

A

high clay content and low OM content

107
Q

What is the most significant effect of suspension-type wind erosion?

A

removes clay and SOM reducing soil fertility

108
Q

What type of erosion is greater on soils with level topography?

A

wind erosion

109
Q

What is the difference between nutrient adsorption and nutrient absorption?

A

absorption is when ions dissolved in water are taken into plant roots
adsorption is when ions are attached to surface of charged particles

110
Q

What is nutrient adsorption?

A

when nutrients are attracted to surface of clay in a way they become loosely held to these particles.

111
Q

Which soil zone is most at risk for erosion?

A

brown

112
Q

Which agricultural management method has been crucial in reducing wind erosion?

A

adopting no till

113
Q

What is the main factor that affects clod size?

A

soil texture

114
Q

Which process is responsible for most wind erosion?

A

saltation. accounts for 50-90% of wind erosion.

115
Q

What is negative erosion?

A

removal of soil or rock by wind or water

116
Q

What is positive erosion?

A

deposition in another place

117
Q

What is accelerated erosion?

A

due to human activity. can be 10,000 times as destructive as geological (natural) erosion

118
Q

What are the 3 types of wind erosion?

A

creep, saltation, suspension

119
Q

What is “creep” erosion?

A

rolling of aggregates of about 1mm. coarse sand. fills in furrows, resulting in a level surface. accounts for 5-25% of wind erosion.

120
Q

What is ‘saltation’ erosion?

A

medium to fine sand aggregates ‘jump’ and break up larger particles moving more aggregates

121
Q

What is ‘suspension’ erosion?

A

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
Q

Which type of wind erosion affects soil fertility?

A

suspension

123
Q

Which texture of soil have the greatest risk for wind erosion on the prairies?

A

coarse textured soils. sand, sandy loam, loamy sand

124
Q

What is the effect of SOM on increasing soils resistance to wind erosion?

A

it helps forming and keeping aggregates together

125
Q

What is fine earth fraction vs coarse fragments?

A

fine earth fraction is sand silt and clay <2mm
coarse fragments are boulders stones cobbles and gravel

126
Q

As particle size decreases, specific surface area _______?

A

increases

127
Q

A handful of clay has what surface area?

A

5 acres

128
Q

A handful of sand has what surface area?

A

1 acrea

129
Q

Why do clay particles behave like colloids?

A

because of their extremely small size

130
Q

What is a plow pan?

A

Hard compacted area just below soil surface

131
Q

What property does a penetrometer measure that is also an indicator of soil compaction?

A

Soil strength

132
Q

When using a penetrometer what does a reading of > 300 psi mean?

A

Too compacted for root growth

133
Q

Methods for plow pan correction?

A

Subsoiling - ripping
Tillage radish
Moldboard - old technique that digs up and turns soil over. Not used much anymore

134
Q

Which varies more bulk density or particle density?

A

Bulk density

135
Q

Which horizon / suffix is used for the presence of secondary carbonates?

A

Cca
White spots are visible

136
Q

What horizon is is used when there are primary carbonates (non visible)?

A

Ck

137
Q

Which soil structure is associated with soil high in sodium?

A

Columnar

138
Q

What soil structure is associated with eluviated horizons?

A

Platy (Ae)

139
Q

What is a representative soil sample?

A

One taken following proper procedures

140
Q

What is a control sample?

A

Non contaminated sample

141
Q

What is the expected depth of tillage?

A

6 inches

142
Q

Which nutrients are already found in western Canadian soils due to free lime rich parent material?

A

Ca and Mg

143
Q

What is a moldboard?

A

Curved iron plates attached to tractor

144
Q

What should soil moisture be when using a penetrometer?

A

100% capacity

145
Q

What is clay dispersion?

A

Caused by sodium. Clay particles separated from each other

146
Q

What are clods?

A

Management induced aggregates

Soils (3 decks)

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