The Solid Earth - Chapter 2: Soil Flashcards
____ and other processes create soil
Weathering
What carry out the intermediary role of assimilating the necessary elements and making them available to animals and people to support life?
Plants
The earth’s land surface is covered by ___, the layer of rock and mineral fragments produced by weathering
Regolith
Soil is a combination of ____ and ____ matter, matter, and air
Mineral
Organic
About ____ percent of the total volume of a good quality surface soil is a mixture of disintegrated and decomposed rock and humus
50
The decayed remains of animal and plant life (organic matter)
humus
The remaining half (not rock and humus) consists of ___ spaces for air and water to circulate
Pore
Humus enhances the soil’s ability to ___ ____.
Retain water
Soil water is a complex solution containing many ___ nutrients
soluble
This refers to the relative portions of different particle sizes in a soil
Soil texture
What do sandy soils do too rapidly?
Drain
The pore spaces of clay-rich soils might be too small for adequate ___
drainage
This type of soil is 10 percent silt, 40 percent clay, and 50 percent sand
Sandy clay
What are soils called that have no single particle size predominating?
Loam
Which type of soils are best suited to support plant life?
Loam
Soil particles often form clumps called
peds
Name four basic soil structures:
platy
prismatic
blocky
spheroidal
Prismatic and blocky peds usually allow for moderate ___ ____
water infiltration
Platy and spheroidal structures are characterized by slower ____ ____
infiltration rates
The source of the weathered mineral matter from which soils develop is called the ___ ___ and is a major factor influencing a newly forming soil
Parent material
When the parent material is bedrock, the soils are termed
residual
Soils developed on unconsolidated sediment are called
transported
transported soils form __ ___
in place
Transported soils form in place on parent materials that have been carried from elsewhere and ___ by gravity, water, wind, or, ice.
deposited
True or false: the parent material of the soil affects how it weathers.
True
Can the parent mineral influence the rate of chemical weathering?
yes
The chemical makeup of the parent material will affect the ___ of the soil
fertility
Name a factor that is more important than parent material in determining characteristics of a soil
climate
True or false: Regardless of time, a parent material will always have the same strong effect on soil
False
The longer a soil has been forming, the ___ it becomes and the less it resembles the parent material from which it formed
thicker
____ is considered to be the most influential control of soil formation
Climate
The chief function of plants and animals is to supply ____ _____ to the soil
organic matter
When organic matter is decomposed, it supplies important nutrients for plants, as well as food for the animals and _______ living in the soil
microorganisms
The decay of plant and animal remains causes various organic ___ to form
acids
Complex acids (quicken/slow) the weathering process
quicken
On steep slopes, soils are often ____ developed
poorly