factors of soil formation Flashcards
what are the 5 factors that cause soils to be different from one location to another
parent material, climate, topography, time, organisms
what does parent material influence
soil texture
soil mineralogy
where does soil formation begin
raw geologic (rocks, sediments) and organic materials (peat)
how is parent material classified
residual (or sedentary)-developed in place
transported-material moved from one location and deposited
what is an example of residual soils
organic soils developed in wetlands: or mechanical weathering of rocks
what is transported soils
materials moved from one location and deposited to another by gravity, water, wind, glaciers
what breaks down parent material
mechanical and biological weathering
how was most parent material transported
glaciers
what is glacial advanced
Glaciers ground-up rock into sand, silts, and clays, and transported and mixed the materials
what is glacial retreat
glaciers left behind unsorted sediments as they melted
and reworked (sorted) by wind and water(from melting glaciers more recently)
what is glacial till parent materials
it is raw material that glaciers left behind. it is a heterogeneous mixture of particle sizes (boulders, stones, sand, silt, and clay). it is the most common parent material in the Canadian prairies. results in kettle topography (hummocky)
what is hummocky
is a non‐genetic, descriptive term applied to landscapes with irregular hills and depressions
what happens to glacial lacustrine parent material
- silt and clay deposited in a glacial lake
- creates flat topography
- gives rise to the most productive soils
what are glacial fluvial parent material
soil formed from fast-flowing water. and it would carry gravels and coarse sand
what are the different names of recent (post glacial) parent material
aeolian parent material, alluvium, peat
what is aeolian parent material
wind deposited material
forms sand dunes
what is alluvium
- mixture of sand, silt, and clay deposited by rivers and streams
- it is young fertile soils which are great for agriculture
what is peat
- it is organic parent material
- sphagnum and or sedges accumulate in peat deposits in a very wet boggy area
- peat areas can be very productive if they can be properly drained
what effects does climate have on soil formation
soils produced from the same parent materials will differ under different climates
climate governs the rate and type of soil formation and it is also the main determinant of vegetation distribution
what are the two components of soil climate
moisture (precipitation)
temperature (influences evaporation)
what happens when precipitation exceeds evaporation
leaching of materials (clay, nutrients, SOM) from the soil profile will occur
what do precipitation and temperature control the rate of
weathering
what effects does a hot, humid climate have on soil
- fast soil development
- faster weathering and leaching of nutrients and organic matter
what effects does a cool, dry climate have on soil
slower soil development higher fertility (limited leaching of nutrients, clay, and organic matter
what things play a role in organisms effect on soil
plants
roots
microorganisms
how do plants influence soil development
the nature of the SOM is determined by the vegetation cover and resultant litter inputs
how do roots influence soil development
they contribute dead roots to the soil, bind soil particles together, and affect soil structure
how do microorganisms such as bacteria and fungi affect soil development
assist in the decomposition of plant litter. it is mixed into the soil by microfaunae (soil animals) such as worms and beetles
what effect does burrowing animals have on the soil
make soil horizon is less distinct
what is topography
the lay of the land or the arrangement of the natural and artificial physical features of an area
what effects does topography have
- modifies the effect of climate
- slope affects water runoff
- aspects affect temperatures, creates microclimate conditions
what happens to the temperature with elevation
as the elevation increases temperature decreases and precipitation increases
what is an example of microclimate conditions
south-facing slopes are warmer in the northern hemisphere
what are some characteristics of young soils
little profile development
Weakley weathered
little clay movement
what are some characteristics of old soils
well developed horizons
secondary minerals
more time for pedogenic processes to occur
do we consider Saskatchewan soils old or young
we consider sask soil as young
what are the benefits of young soils compared to old soils
young soils carry lots of nutrients like P, K, and Ca
where old soils are weathered and have lost much of their original fertility due to erosion and leaching
