Web Exam 2
Soil Science WEB Exam 2 --Fall 2009-- 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 silt 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 silt 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. The reason a hydrometer will work for determining the percent sand, silt and clay in a soil is because ........
a) the density of the water solution is greater when silt and clay are in suspension.
b) larger particles have a smaller density
c) silt and clay particles create greater viscosity that keeps the hydrometer from falling into 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 sand in suspension.
c) the reading at 40 seconds measures the amount of clay in suspension.
d) the two hour reading measures the amount of clay in suspension.
5. Determine the amount of sand, silt and clay in a 60 gram sample of soil that had 2 hour reading of 6 and 40 second reading of 16. The temperature correction is not needed.
a) % clay is 20, b) % sand is 73, c) % silt and clay is 44, d) % silt is 10
6) The textural class name for the soil in question 5 is ____
a) Sandy Loam b) Loam c) Loamy Sand d) Sandy Clay loam
7) What is the textural class name of a soil with 25% clay, 25% silt and 50% sand?
a) loam b) sandy clay loam c) silt loam d) clay loam
8. Which textural class name is incorrect (or is not a "real" texture name)
a) silty clay loam b) silt loam c) sandy loam d) silty clay sand e) sandy clay
9. A sandy clay loam will have at the minimum _______% clay, while a clay loam can have a maximum of ____% clay.
a) 20.... 28; b) 35......55; c) 20 ..... 40; d) 35....40
10. The % Clay for the E and B horizons for four soils is in the following table, which ones have a textural profile .
a) soil a; b) soil b; c) soil c; d) soil a & d
|
Soil |
E % Clay |
Bt % Clay |
|
a |
11 |
19 |
|
b |
26 |
26 |
|
c |
15 |
5 |
|
d |
30 |
40 |
11. Which soil texture is described by this statement: " moderately sticky, smooth and silky with no grit", makes a medium ribbon and feels very smooth"
a) loam b) clay loam c) silty clay loam d) silt loam
12. A very heavy rainfall (5 inches) event takes place in 2 hours on a very flat landscape. The soil here has a sandy surface and does not have a textural profile. If all the water entered the surface soil (there was no runoff) you would expect to find in a few days ______.
a) The surface soil saturated because the water could not quickly penetrate the subsoil.
b) The subsoil and below would be wet but not saturated since the water moved through the sand and through the profile and into the ground water.
c) only the subsoil would be saturated.
13. If a soil below the septic drain field is a clay 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. The soil ped from the subsoil is showing evidence of clay translocation into the subsoil horizon. The visual evidence for this would be___?__.
a) a glossy coating that is shiny and somewhat darker than the surrounding soil
b) a silky coating that is redder than the surrounding soil
c) a dark gray splotch surrounding by red color
d) shiny side to the ped that looks like it has been smeared
15. Select the answer that definitely ranks the soil texture classes from less clay to more clay.
a) loam -- sandy loam -- silty clay loam
b) sandy clay loam -- loamy sand -- silt loam
c) loamy sand -- sandy loam -- sandy clay loam
d) sandy loam -- loam -- silt loam
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