Tutorial2_30177967
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School
University of Calgary *
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Course
204
Subject
Geography
Date
Dec 6, 2023
Type
Pages
3
Uploaded by AdmiralSpider605
Name:
Katie Findlay
Student ID: 30177967
Question #1
Describe the values and spatial patterns of soil erosion rates as shown in Figure 1A for the
continents given in the table below. Note that while Figure 1a is found on Page 3 of the article,
the figure caption for Figure 1a is on Page 4 of the article. Note: You do not have to provide
explanations for the values; this exercise is focused on describing the data and patterns in the
data.
Note: Answers in this table must be given in point form.
Table 1. Soil Erosion
Continent
Answers to question
North America
•
The majority of North America has very low, and low soil erosion
rates, Canada especially (dark green: approx. 85% is at 0-
2 mg ha−1
yr−1).
•
The peak of soil erosion in North America that is exceeding the
generic tolerable soil erosion is mainly in the Mid-Western States
(yellow & orange: approx. 15% is at 5-
20 mg ha−1 yr−1)
•
The peak of soil erosion in North America that is exceeding the
generic tolerable soil erosion is partially covering the South-Eastern
States (yellow: approx. 10% is at 5-
10 mg ha−1 yr−1 at peak)
South America
•
The majority of South America has very low, and low soil erosion
rates (dark green: approx. 60% is at 0-
2 mg ha−1 yr−1).
•
The peak of soil erosion in South America that is exceeding the
generic tolerable soil erosion is mainly in Peru and Brazil (yellow &
orange: peak areas in those countries are approx. 35% is at 10-50 mg
ha−1 yr−1)
•
The peak of soil erosion in Argentina is also exceeding the generic
tolerable soil erosion (yellow: approx. 20% is at 5-
10 mg ha−1 yr−1)
•
Small parts of areas around and including Chile have no data
recorded for soil erosion (grey: approx. 5% is missing data)
Africa
•
The majority of Africa with data has very low, and low soil erosion
rates (dark green: approx. 35% is at 0-
2 mg ha−1 yr−1).
•
Northern Africa for the most part has no data collected for soil
erosion (approx. 30% grey)
•
The peak of soil erosion in Africa that is exceeding the generic
tolerable soil erosion is mainly in Eastern and Western Africa (yellow
& orange: peak areas in those countries are approx. 20% 10-50 mg
ha−1 yr−1)
•
The highest peaks of soil erosion in Africa are in Ethiopia, Rwanda,
and Burundi (darker orange-light red: approx. 8% is at 20- >50 mg
ha−1 yr−1)
Asia
•
The majority of Asia has very low, and low soil erosion rates (dark
green: approx. 50% is at 0-
2 mg ha−1 yr−1).
•
Northern China and areas around and including Saudi Arabia for the
most part has no data collected for soil erosion (approx. 20% of Asia
is grey)
•
The peak of soil erosion in Asia that is exceeding the generic
tolerable soil erosion is mainly around China and India (yellow &
orange: peak areas in those countries are approx. 20% is at 10-50 mg
ha−1 yr−1)
•
The highest peaks of soil erosion in Asia are primarily in and around
China as well as North-Eastern parts of Russia (darker orange-light
red: approx. 10% is at 20-
>50 mg ha−1 yr−1)
Question #2
Table 2. Answers to questions on soil erosion video. Note: Answers in this table must be given in
point form.
Question
Answer
State the names of the 3 types of water erosion
for soils discussed in this video. Note: You do
not have to describe the processes (state only the
names).
•
Sheet
•
Rill
•
Gully
What location mentioned in the video has 80%
of water erosion of soils resulting from spring
runoff?
•
Peace River area
Question #3
Type your answer below. Please follow word limit and rules/instructions provided on the
question sheet. Your answer must be written in full sentence format (*not* point form).
Dave Montgomery is a geologist that wrote a book about soils called
Dirt: The Erosion of
Civilizations
.
He conducted research for his book by composing data of rates of soil erosion from
about 1,400 various papers from the library. He focused on the data on rates of soil erosion from
agricultural systems as well as long term natural rates of soil erosion, which is soil erosion under
natural and uncropped conditions. He compares the rates of soil erosion from agricultural fields
under standard plow-based agriculture to geologic erosion rates from alpine areas, low-gradient
cratons, and soil-mantled areas. Montgomery's graph is a comparison of the rates of soil erosion
from four kinds of data, three out of the four being geological erosion rate data. The four types of
data collected includes: agricultural, cratons, soil-mantled, and alpine. The y-axis of his graph is
demonstrating the data on erosion rate. On the left-hand side of
Montgomery’s
graph, the erosion
rate measurements begin at a ten thousandth of a millimeter a year whereas the right-hand side at
the highest measurement on this graph is at a decimeter a year. The white data symbols on the
graph represent geological erosion data: cratons, soil-mantled, and alpine. The black data
symbols on the graph represent standard plow-based agriculture. Soil-mantled and craton, which
are low-gradient terrain, are typically where people choose to farm as they have much slower
erosion rates compared to alpine areas which erode significantly faster. Erosion rates vary
significantly around the planet but conventionally plowed agricultural lands are eroding at an
unsustainable rate, the soils are not built up as much as they are being lost. The USDA defines
sustainable agriculture as a loss tolerance of soil between about 0.4 millimeters a year to 1.0
millimeters a year. In conclusion, Montgomery's graph is important because it demonstrates that
hillslope soil production and erosion evolve to balance the amount of erosion to the amount of
soil being produced, but conventional plow-based agriculture increases erosion rates to the point
of being unsustainable which results in loss of fertile land for agricultural purposes.
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