PLS 366 EXAM 2 QUESTIONS & ANSWERS
3 primary properties used by soil scientists to delineate soil horizons - Answers -Color
Texture
Structure
Soil represents approximately this percentage of a loam soil at field capacity - Answers
-~ 50% (Minerals + OM)
An accumulation of silicate clays in this horizon is labeled with a subscript "t" - Answers
-B
Ions freely available for absorption by plant roots are found in this fraction - Answers -
soil solution fraction
Key functions of soil in an ecosystem - Answers -Medium for plant growth
Regulates water
Recycles nutrients
modifies atmosphere
habitat for organisms
engineering medium
The degradation of OM from plant residues is considered this type of soil profile
development process. - Answers -Transformation
The top horizon of a soil developed under a forest is called this - Answers -O or
Organic horizons
Limestone parent material weathers into this bivalent cation which is an example of
what kind of weathering? - Answers -Ca2+
Chemical
Name the 5 soil forming factors - Answers -Parent Material
Time
Topography
Climate
Biota
This type of parent material was long ago transported by water and deposited in a lake
from which soils were then formed - Answers -Lacustrine
Soils in the Sonoma Desert would likely be classified within what Soil Order? - Answers
-Aridisols
3 primary properties used by soil scientists to delineate soil horizons - Answers -Color
Texture
Structure
Soil represents approximately this percentage of a loam soil at field capacity - Answers
-~ 50% (Minerals + OM)
An accumulation of silicate clays in this horizon is labeled with a subscript "t" - Answers
-B
Ions freely available for absorption by plant roots are found in this fraction - Answers -
soil solution fraction
Key functions of soil in an ecosystem - Answers -Medium for plant growth
Regulates water
Recycles nutrients
modifies atmosphere
habitat for organisms
engineering medium
The degradation of OM from plant residues is considered this type of soil profile
development process. - Answers -Transformation
The top horizon of a soil developed under a forest is called this - Answers -O or
Organic horizons
Limestone parent material weathers into this bivalent cation which is an example of
what kind of weathering? - Answers -Ca2+
Chemical
Name the 5 soil forming factors - Answers -Parent Material
Time
Topography
Climate
Biota
This type of parent material was long ago transported by water and deposited in a lake
from which soils were then formed - Answers -Lacustrine
Soils in the Sonoma Desert would likely be classified within what Soil Order? - Answers
-Aridisols
