Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ENVB 210 > Hydrosphere I > Flashcards

Hydrosphere I Flashcards

1
Q

Give 5 examples of the influence of soil water on ecosystems.

A
  • Creates wetlands
  • Causes soil particles like clay to swell and shrink
  • Provides water for plants and soil organisms
  • Part of chemical reactions that release and tie up plant nutrients
  • Influences the flow of gases and solutes
  • Affects rate of organic material decomposition
  • Impacts erosion and weathering rates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the 2 major properties of water as a result of its polarity.

A

Cohesion and adhesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is water cohesion?

A

Attraction forces between the same molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is water adhesion?

A

Attraction forces between two different molecules (i.e. water and something else)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the consequence of cohesion on water movement in soil?

A

Water molecules tend to group together, and can form drops.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the consequence of adhesion on water movement in soil?

A

Since water is polar and organic matter and soil particles are negative (especially clay), water is attracted and held in soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe two features of soil that will increase water retention.

A

More clay and more organic matter due to their negative charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 main types of water found in soil?

A

Gravitational, capillary, and hygroscopic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe what hygroscopic water is.

A

It is water held in the soil by adhesion in a thin film around the particles. It is strongly attracted to the particles such that the water is not accessible to plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can hygroscopic water be removed from soil?

A

The only way is by oven-drying. It will not leave on its own or be taken up by plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe what capillary water is.

A

Capillary water is held by both adhesive and cohesive properties. It stays and moves in the soil, as the forces keeping it there outweigh gravity. It is available to plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Capillary water moves through the soil via […]

A

Capillary action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is capillary action?

A

It is the movement of a liquid through or along the surface of another material in spite of other forces, such as gravity. It depends on adhesion and cohesion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Capillary action moves water from […] areas to […] areas.

A

Wet, dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the primary force moving water through unsaturated soil?

A

Capillary action.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What two factors affect how far soil water will move via capillary action?

A

The diameter of the capillary tube (soil pore) and the total amount of water in soil (in wetter soils, gravity will be more relevant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does pore diameter affect capillary rise? Why?

A

Water will rise higher in smaller pore diameters, as the cohesive and adhesive forces in small pores have a stronger pull.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does pore diameter affect speed of capillary rise? Why?

A

Because in smaller pores, adhesion and cohesion forces are stronger, which cause more friction on the water’s up, slowing its ascent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Compare sand and clay in terms of capillary rise behaviour.

A

In sand, the water will rise faster but less high, while in clay, the water will rise slower but higher.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe what gravitational water is.

A

It is freely moving water in soil right after rain or irrigation. It is not always available to plants because it spends a short time in the soil before being drained out by gravity through macro pores.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What type og pores are most likely to support gravitational water?

A

Macropores.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain the conditions that allow for gravitational water.

A

Soil gravitational water occurs when soil particles are too far apart, such as in macropores, to support adhesion and cohesion to counteract gravity. It also occurs when pores are saturated or in large earthworm burrows or root channels

23
Q

How do soil conditions vary under poor drainage vs good drainage?

A

Water moves slower, there tends to be high surface runoff and groundwater levels, saturated conditions and lack of oxygen, and buildup of excess salts.

24
Q

Name 3 ways to improve soil drainage.

A

Build aggregates, rooting channels, and reducing compaction

25
Q

Explain how soil texture affects the movement of soil water through the soil.

A

In soils with larger pores, gravity is more dominant, so water moves downward first and foremost rather than sideways. In soils with smaller pores, capillary action is more dominant, so water will move laterally rather than downwards right away.

26
Q

What is a benefit of increase capillary action versus gravity for plants?

A

Water travelling further sideways provides plants with access to nutrients that are further away.

27
Q

Name the major critical levels of water in the soil and their consequences on plants.

A

Saturation: the soil is completely full of soil, which will cause the plant to wilt.
Field capacity: there is the perfect amount of water for growth, which will lead to healthy plant.
Wilting point: there is not enough water for growth, so the plant will wilt.

28
Q

What is plant available water with relation to critical levels of water in soil?

A

It is the amount of water between field capacity and wilting point.

29
Q

When soil is saturated, what type of water is dominant?

A

Gravitational water

30
Q

When soil is at wilting point, what type of water is dominant?

A

Hygroscopic water

31
Q

What is field capacity?

A

The amount of water in soil after free drainage has removed gravitational water. It is the maximum of water held in the soil that’s available for plants.

32
Q

Explain why field capacity is ideal for plants.

A

There isn’t gravitational water, which isn’t available due to its short residence time, Also, there is optimal aeration, where micropores are filled with water but macropores are filled with air.

33
Q

Compare sand and clay in terms of plant available and unavailable water and explain why.

A

Clayey soils hold more water overall and have more plant-available water than sand. However, they also hold more plant unavailable water than sand, as the water in the micropores is often strongly held by adhesion and cohesion.

34
Q

What type of soil has the highest amount of available water?

A

Loam

35
Q

What effect does organic matter have on available water?

A

It increases it

36
Q

Explain how cover crops affect water infiltration into soils.

A

Having cover crops prevents soils from getting flooded when there’s heavy precipitation, allows them to more effectively hold water without flooding.

37
Q

Explain how an increase in no-till practices can allow for decreased summer-fallow.

A

No till leaves residues on the soil surface, which keeps the soil covered. This increases water content in the soil. On the other hand, summer fallow increases erosion and leaves the soil vulnerable to flooding, as it is bare. So, no till eliminates the need for summer fallow, whose primary goal is to increase soil water for the next round of crops.

38
Q

What is the formula for soil water storage?

A

(Precipitation + irrigation) - (runoff + evapotranspiration + percolation)

39
Q

Why isn’t infiltration considered an input for soil water storage?

A

Because percolation is the movement of this water through the soil. Infiltration is just the rate at which this water enters, and is not itself an input.

40
Q

Describe the relationship between rainfall, infiltration, and flooding when rainfall is less than or equal to infiltration.

A

When rainfall is less than or equal to infiltration capacity, there is no runoff. The infiltration rate will be the same as the rainfall rate.

41
Q

Describe the relationship between rainfall, infiltration, and flooding when rainfall is greater than infiltration.

A

When rainfall is greater than the infiltration capacity, the infiltration rate is equal to the infiltration capacity and any excess rainfall will be converted to runoff.

42
Q

Describe how prairie potholes interplay with water infiltration rates and percolation.

A

When rain falls faster than infiltration capacity, water can pond on the soil surface and stay in depressions. If the rate of infiltration is very low, the water can remain in depressions for a long time.

43
Q

Name 4 consequences of runoff.

A
  1. Contributes to non-point pollution if runoff contains contaminants
  2. Erodes soil and landscapes
  3. Flooding
  4. Rapidly increases river flow
44
Q

Describe a solution to runoff and its contribution to pollution.

A

By having a vegetated buffer zone along which runoff can flow, the plants can uptake some of the excess nutrients in the water to lessen their impact on the rest of the environment.

45
Q

Give 2 examples of urban solutions to decreasing runoff.

A

Using permeable pavers or redirect runoff from parking lots into rain gardens.

46
Q

Name 2 examples of farming solutions to decreasing runoff and increasing soil retention.

A
  1. Planting buffer strips at the edge of a field to reduce runoff and catch nutrients
  2. Leaving last year’s crop residue on the surface to protect the soil from water erosion and increase OM, which improves water infiltration by encouraging soil aggregation.
47
Q

How do soil fauna affect soil water retention and infiltration?

A

They improve it by creating tunnels, thus increasing the amount of water soil.

48
Q

Name and describe the 3 steps of soil erosion by water.

A
  1. Detachment: raindrop impact destroys soil aggregates and detaches soil particles
  2. Transport: particles are transported downslope by water
  3. Deposition
49
Q

What are the 3 types of water erosion?

A

Splash, sheet, rill and gully.

50
Q

What is splash erosion?

A

Splash erosion is the displacement of soil particles due to the impact of raindrops.

51
Q

What is sheet erosion?

A

It is the movement of water downslope, weathering the soil as it goes.

52
Q

What is rill and gully erosion?

A

It is when erosion causes grooves in the soil along which water can move. These can end up as permanent features if they are not managed. Rills becomes larger gulleys.

53
Q

What is the impact of the presence of roots and grasses on runoff and erosion?

A

It will decrease the amount of erosion from runoff, as the soil will be held in place by the plants.

54
Q

What is contour farming and what is its purpose?

A

Creates contours, which are perpendicular to the slope, help retain water in a field and slow its movement down a slope.

ENVB 210 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions