Lab 1 Flashcards
Characteristics of 1st soil surveys
- 1899
2. simple/limited
3 cons about soil surveys?
- time consuming
- expensive
- difficult to carry out
Soil surveys are a starting point towards what?
intelligent land use decisions
What is the 3 most important objective of a soil survey?
- predict adaptability of soils to various crops, grasses, trees
- predict behaviour/productivity under different management systems
- predict yields of adapted crops under defined sets of management principles
How many soil series are there in CAD?
3000 +
Scale of soil surveys is often too large for ________.
farm fields
what are the 2 parts of soil surveys?
- repot
2. map
In a soil survey, the soil shown in any one area consists of how many kinds of soils? What is this soil shown called?
- 1 + small inclusions of others
2. mapping unit
What is the difference between a map scale of 1:5,000 and 1:50,000 (area contained in 1 cm^2 on map)
1: 5,000
- large scale
- large ratio
- small area
- detailed
- 2,500 M^2
- 1/4 ha
1: 50,000
- small scale
- small ratio
- large area
- generalized
- 250,000 M^2
- 25 ha
The products of mineral and rock weathering are generally divided into what 2 groups?
- sedentary or residual
2. transported
What are sedentary products?
Those derived from the weathering of solid rocks in place
What are transported materials?
Those moved from the point where the parent rock out cropped
origin of sedentary material
single lithology
origin of transported material
several different lithologic units
Are nutrient deficiencies more likely to occur in soils developed in place (sedentary) or or in soils developed from transported material?
sedentary
Transported groups - materials moved by water: (3)
- alluvial (rivers) - vary in particle size
- lacustrine (lake basins)
- marine (ocean basins)
Transported groups - materials moved by wind: (2)
- loess
2. dune sand
Transported groups - materials moved by ice: (2)
- till
2. glacial fluvial
Transported groups - materials moved by gravity: (1)
colluvial
Rapidly moving streams deposit what type of material?
coarse gravel and sand
Slowly moving streams deposit what type of material?
silt
Characteristic of alluvial deposits
stratified & well sorted
What 2 type of soils are usually of lacustrine origin?
clay and silt
Layer type - lacustrine
varying layers due to regular seasonal accumulation of silt and clay
Lacustrine: sediment texture near shore vs sediment texture away from shore?
Coarse near shore, finer farther out
Marine deposits contain high amounts of what?
quartz & other resistant materials
Characteristics of Marine deposits?
- low in nutrient elements
- stratification + shells
- Well sorted
Loess is very high in _____ content
silt. + some clay and minor sand content
uniform in composition
sand dunes
poor soils
What is glacial till?
material that has been picked up, ground up, and deposited directly by glacial ice.
What are tills composed of?
rocks and their products of weathering
Characteristics of till
- random assortment
- extremely compact
- many different sources
- may have traveled really long distances
What is glacial fluvial material? Also called?
Also called outwash
materials of glacial origin carried and deposited by flowing streams
3 characteristics of glacial fluvial drift material?
- stratified
- sorted
- extremely variable
- nutrient poor
How does glacial fluvial material differ from glacial till in terms of soil composition?
more silt
What are colluvial deposits?
accumulations of rock detritus commonly recognized as talus and cliff debris or material transported by avalanches and landslides
What is the main driving force of colluvial deposits? What else helps it move?
Gravity - water and ice also help a bit
What term is used to describe the accumulation of organic material in swamps, lakes or ponds?
Cumulose deposit
Are Cumulose deposits transported?
No, occur in situ
