Assignment 9 Soils
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School
University of Texas, El Paso *
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Course
MISC
Subject
Geography
Date
Feb 20, 2024
Type
Pages
4
Uploaded by DeaconPrairieDog3792
Exercise 27 Problems
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Part I Using Figure 27-1, the standard soil texture triangle, answer the following questions. 1)
Determine the soil texture for the following combinations of sand, silt, and clay. a)
Sand 20 percent; Silt 20 percent; Clay 60 percent: Silt Loam b)
Sand 60 percent; Silt 30 percent; Clay 10 percent: Sandy Loam c)
Sand 50 percent; Silt 10 percent; Clay 40 percent: Sandy Clay 2)
Determine a representative combination of sand, silt, and clay for the following soil textures. a)
Silty Clay: Sand 50%; Silt 50%; Clay 50% b)
Silty Loam: Sand 30%; Silt 70%; Clay 10% c)
Loam: Sand 60%; Silt 40%; Clay 20% 3)
A) Will soil composed of a combination of sand 90 percent, silt 5 percent, and clay 5 percent tend to have high or low porosity? It will have low porosity. B) Will this soil tend to have high or low permeability? High permeability. c. Is such soil likely to dry out quickly? Yes, it will dry out quickly. d. Why? The sand has coarse grains, the chance of flow of water is high. 4) a. Will soil composed of a combination of sand 10 percent, silt 20 percent, and clay 70 percent tend to have high or low porosity? High porosity. b. Will this soil tend to have high or low permeability? Low permeability. c. Is such soil likely to allow the rapid infiltration of water from the surface? It will not. d. Why? The high clay content will prevent water from infiltrating quickly from the surface. 5) In terms of porosity and permeability, why is loam often considered the ideal soil texture for agriculture? The loam soil will have both high porosities to hold water and moderately high permeability from drying out too quickly.
Exercise 27 Problems
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Part II
1)
Using a colored pencil, draw in lines marking the approximate boundaries between the three most obvious soil horizons in this profile. 2)
Based on their general appearance and position, name the most likely soil horizons visible in this profile. a.
Top zone: A horizon b.
Middle zone: E horizon c.
Bottom zone: C horizon 3)
What suggests that eluviation has taken place within the middle horizon? Eluviation zone will be called a light-colored zone at the lower part of A horizon or below A horizon. 4)
a. Is unaltered parent material (the R horizon) visible in this soil profile? The lower region of the soil suggests the presence of the R horizon. The depth of the horizon is nearly 40 inches. b. Is this soil more likely to have developed in a flat area or on a steep slope? The soil has developed into a flat area with a gentle slope. c. How do you know? The eluvial deposit in the eluviation zone is horizontal, suggesting the area slope is gentle. Exercise 27 Problems
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Part III
1)
a. Climate: Tropical humid climates b. Biome: Tropical rainforest c. Likely pedogenic regime: Most likely regime would involve intense weathering and leaching. d. What makes this the most likely pedogenic regime? Due to high temperatures, heavy rainfall, and dense vegetation. 2)
a. Climate: Hot Dry b. Biome: Desert c. Likely pedogenic regime: Most likely regime is often dominated by salts and calcium carbonate as well as limited moisture d. What makes this the most likely pedogenic regime? Limited moisture in the air slows down chemical weathering 3)
a. Climate Mild midlatitude climate b. Biome: Mediterranean shrublands c. Likely pedogenic regime: Influenced by moderate temperatures, moderate to high precipitation, and vegetation. d. What makes this the most likely pedogenic regime? High precipitation and moderate temperatures support the breakdown of minerals through weathering. 4)
a. Climate: Severe midlatitude b. Biome: Boreal forests c. Likely pedogenic regime: Cryoturbation and accumulation of organic matter in the soil due to slower decomposition rates because of the cold temperature. d. What makes this the most likely pedogenic regime? The cold temperature and seasonal freezing can lead to distinctive soil features like permafrost. 5)
a. Climate: polar climate b. Biome: Tundra c. Likely pedogenic regime: Heavily influenced by permafrost and cryoturbation. Chemical weathering rates are slow due to cold temps. d. What makes this the most likely pedogenic regime? Permafrost plays a role in polar soils. Exercise 28 Problems
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Part I
1)
What is the contour interval? 50 Feet 2)
What is the elevation of Point A? 770 feet 3)
What is the elevation of Point B? 675 Ft 4)
What is the elevation of Point C? 570 ft 5)
Which lettered point has the highest elevation? E 6)
Which lettered point has the lowest elevation? C 7)
a. Where is the highest elevation shown in this landscape? At Rock Hill b. What is the elevation of this highest location? 1120 Ft 8)
a. Where is the lowest elevation shown in this landscape? Around Rush creek b. What is the elevation of this lowest location? 420 ft 9)
What is the “local relief” of this landscape?
700 ft 10)
Which lettered point is most clearly on a spur or ridge running down the side of a hill? F 11)
Is it possible to see D from F? No 12)
Is it possible to see D from B? Yes 13)
What is the elevation at the bottom of the depression southwest of Pine Hill? 525 Ft 14)
How deep is the depression? Lip is 600 ft. Bottom of depression is below 550 ft. Depth of depression is close to 75 ft. 15)
What is the horizontal distance from C to B? 5,800 ft
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16)
In which direction does Rush Creek flow? From North to South 17)
Draw a 1 cm diameter circle around the steepest slope on the map. 18)
Draw in three more streams as indicated by the contour patter.