Web Exam 2
Soil Science WEB Exam 2 --Fall 2008-- Dept. of Soil, Water and Climate
Directions 1. There is ONE BEST answer per question. 2. Place your answers on answer sheet, you only need to turn in the answers.
Name ___________________________
1.________ 2._______ 3._________ 4._______ 5.______ 6._______ 7._________ 8._______
9.______ 10._______ 11. _________ 12.________ 13.______ 14.________ 15._________
Total _____
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Soil Texture
1. The soil separate sand will have a particle size between ____ and ____ mm.
a) .05 to .100 b) .002 to .0500 c) .05 to 2.00 d) 0 to .002
2. The soil separate clay is made by ___?__.
a) the action of chemical weathering
b) the action of soil organisms decomposing organic matter.
c) the running of water to reduce particle size.
d) the grinding action of ice (glaciers) on the sand and gravel size particles.
3. When the hydrometer procedure is used for determining the soil texture the ..... .
a) silt and clay particles create greater viscosity (stickiness) that keeps the hydrometer from falling into the soil/water solution.
b) larger particles have a smaller density so they fall slower
c) hydrometer is raised above 0 by the greater density of the soil-water solution.
d) sand particles create a void after they fall out of suspension and the hydrometer fills the void and sinks.
4. In the Bouyoucos Hydrometer Method of mechanical analysis; the hydrometer is placed in the soil suspension immediately after the suspension has been stirred and a reading is taken:
a) at the end of 40 seconds this reading measures directly the amount of sand that has settled out.
b) the 40 second reading represents the amount of silt and clay in suspension.
c) the reading at 40 seconds measures the amount of clay in suspension.
d) the two hour reading measures the amount of silt in suspension.
5. Determine the amount of sand, silt and clay in a 60 gram sample of soil that had 2 hour reading of 9 and 40 second reading of 19. The temperature correction is not needed.
a) % clay is 15, b) % sand is 83, c) % silt + clay is 52, d) % silt is 15
6) The textural class name for the soil in question 5 is ____
a) Loamy Sand b) Loam c) Sandy Loam d) Sandy Clay loam
7) What is the textural class name of a soil with 25% clay, 55% silt and 20% sand?
a) loam b) sandy clay loam c) silt loam d) clay loam
8. Which textural class name is correct (or is the "real" texture name)
a) silt clay loam b) silty loam c) sandy silt loam d) silty clay sand e) sandy clay
9. A silty clay loam will have at the minimum _______% clay, while a clay loam can have a maximum of ____% clay.
a) 20.... 40; b) 35......55; c) 28 ..... 40; d) 35....40
10. The % Clay for the E and B horizons for four soils is in the following table, which soils have a textural profile.
a) soil a; b) soil b; c) soil c; d) soil c & d
|
Soil |
E % Clay |
Bt % Clay |
|
a |
13 |
12 |
|
b |
26 |
27 |
|
c |
15 |
25 |
|
d |
30 |
40 |
11. Which soil texture is described by this statement: " moderately sticky, some grit and not very smooth", makes a long ribbon and feels "sticky-gritty"
a) loam b) clay loam c) silty clay loam d) sandy loam
12. A very heavy rainfall (5 inches) event takes place in 2 hours Friday morning on a very flat landscape. The soil here has a silty clay loam surface and the soil does not have a textural profile. If there was no surface runoff you would expect to find Friday afternoon ______.
a) the surface soil saturated and standing water above the soil because the water could not quickly penetrate the surface and get into the subsoil.
b) the subsoil and below would be wet but not saturated since the water moved through the soil and through the profile and into the ground water.
c) only the subsoil would be saturated.
13. If the soil below a septic drain field is
a loam texture, the drain field for the septic tank will most likely__?_
a) percolate too slowly and the system will back up.
b) allow the water to percolate easily so the system will function normally.
c) have a rapid permeability and not clean the effluent before it reaches the water table
14. A soil ped that is 25 mm in size has a glossy, wax like coating on the surface that is 2 mm thick. The is visual evidence for ___?__.
a) slickensides or where the soil us rubbing against another ped
b) a clay film that indicates clay translocation.
c) a saturated subsoil
d) the soil not having a textural profile.
15. Select the answer that definitely ranks the soil texture classes from more clay to less clay.
a) loam -- sandy loam -- silty clay loam
b) sandy clay loam -- loam -- loamy sand
c) loamy sand -- sandy loam -- sandy clay loam
d) sandy loam -- loam -- silt loam
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