Soils Flashcards
1
Q
What is soil?
A
an open system composed of weathered rock material and organic material (50%) and air and water (50%)
2
Q
What are the five factors of soil formation?
A
- parent material: the material the soil is derived from
- climate: temperature and moisture characteristics
- biological activity: vegetation, root systems, animals, microorganisms, etc.
- topography and slope orientation: level slopes have thicker soil; steep slopes have thinner soil
- time: the rate of soil development varies by parent material and climate
3
Q
How does agriculture impact soil?
A
soil building is a very slow process and poor farming practices can inhibit that process
4
Q
What are two sustainable farming techniques?
A
- contour plowing: farmers plow perpendicular to the slope of the hill to decrease runoff
- no-till agriculture: farmers leave crop stubble to reduce moisture loss and decrease soil erosion
5
Q
What problems does soil experience in dry environments (3)?
A
- desertification: the increasing expansion of desert territory, frequently caused by poor agricultural techniques
- salinization: build up of salt in the soil
- global climate change
6
Q
What is a soil profile?
A
a vertical section of soil from the surface down to the deepest roots
7
Q
What is a pedon?
A
the smallest unit of soil that contains all of the characteristics used in soil classification
8
Q
What are the six soil horizons?
A
- O: predominance of organic material; humus
- A: “topsoil;” much organic material
- E: sand/silt; leach-resistant materials
- B: accumulation of leach materials
- C: primarily weathered bedrock and parent material
- R: rock
9
Q
What are the six physical properties of soil?
A
- color: determined by chemical makeup of soil
- texture: the proportion of different particles of different sizes in the soil
- structure: the size and shape of different particles in the soil
- consistence: the cohesion of the soil
- porosity: the space between the soil particles which control the flow of air and water in the soil
- moisture: how much moisture the soil can contain
