Unit 2 Flashcards
Out of all the water on earth…how much is Fresh Water?
2.59%
What is in a soil survey?
Describes characteristics of soil
- classifies the soils
- makes predictions about the behavior of soils
what is in the atmosphere and how much of it?
78% N2 21% O2 0.03% CO2
What does N2 stand for?
Nitrogen gas
What are the only forms of Nitrogen that plants recognize?
NO3- and NH4+
(Amonium and Nitrate)
Soil air has ________ CO2 and _______O2 than the atmosphere.
Higher , Lower
Define Diffusion:
A substance moving from an area of high concentration to an area of low concentration.
What is relative humidity?
Amount of moisture that is in the air.
Relative humidity in the soil air is ?
98 - 100% —95% at the lowest
Organic means it contains_________.
Carbon
Define Humus:
The stable end product of decomposition.
What size does a piece of material need to be for it to be considered a Mineral?
2mm in size
Sand size is :
0.05 - 2mm
How big is sand?
0.05 - 2mm
How big is Silt?
0.002 - 0.05mm
How big is Clay?
smaller than 0.002
how can you observe a sand particle?
Naked Eye
How can you observe a silt particle?
Microscope
How can you observe a clay particle?
Electron Microscope
Nutrient holding ability for Sand:
Very Low
Nutrient holding ability for Silt:
Low
The three soil particles that you use to determine the soil texture are what? What is another way to describe them?
Sand, Silt and Clay (Soil Separates)
Organic Matter is one of the soil separates. T or F
False
Different combinations of soil seperates are also refered to as Soil __________?
Texture
Fine Texture soil has a majority of what Soil?
Clay
Course Texture soil has majority of what Soil?
Sand
Define what Coarse Fragments are:
Coarse fragments are materials that are larger than 2mm in diameter.
How many textural classes are possible?
12
Where are Sand, Silt and Clay located on the Soil Triangle?
Define what Loam is:
Soils having a moderate amount of sand, silt and clay.
Sandy Loam has a soil texture somewhat ___________than Loam.
Coarser
A Loamy Sand has a soil texture somewhat _______than sand.
Finer
No Pore Space in soil =
Bad gas and water exchange
Define Soil Structure:
the arrangement of soil particles into secondary units called Aggrogates.
What components form Aggregates?
What do agregates do?
Soil Seperates and O.M.
They create Pore Space
Soil aggregates can be charecterized by their ______, _______ and _______.
shape, size and distinctness
The natural development of Soil Structure is enhanced by what?
Abiotic (physical and chemical) processes such as wetting/drying or freeze/thaw
Biotic processes such as soil compression by roots, burrowing activities of earthworms,
**(Essentially the development can be enhanced by both nonliving and living processes) **
What are the different ways to describe the shape of an aggregate?
Granular
Blocky
Prismatic
Platey
What horizon would you find Granular aggregates?
A Horizon
What horizon would you find Blocky aggregates?
B Horizon
What horizon would you find Prismatic aggregates?
B horizon
Aggregates are destroyed by what?
- Cultivation when it’s too wet
- Falling Rain Drops (soil forms a crust)
- Compaction
Agregation is promoted by what?
- Root Growth
- Addition of O.M.
- Cultivation
describe what aggrogates influence in the soil:
Bulk Density
Porosity
Pore Size
Define: Porosity
Total volume of pores
The type of pore space and the amount of pore space is determined by what?
Parent Material and Aggregates
What are Macropores?
What do they do?
What is their size?
Are there plant roots present?
- the pore space located between the aggrogates
- Transmission of water and air (MOSTLY AIR)
- greater than 6mm
- Yes
What are Micropores?
What do they do?
What size are they?
Are there plant roots present?
- pores that are within the aggrogates
- Water retention
- Less than 6mm
- No
Soil Air vs Atmosphere:
In the Soil there is ________CO2 and _______O2 than the atmosphere.
Higher, Lower
