Lab 3 Flashcards
Soils are best studied…
in situ
5 soil forming factors
time, topography, organisms (biological activity), parent material, climate
What is a soil profile?
a vertical section in which the soil horizons can be seen
What is a horizon?
horizontal layer of soil with similar chemical and physical properties produced by biological, chemical and physical weathering of the parent material
What can soils scientists determine about a soil profile by looking at it?
its limitations
What are 3 examples of limitations that a soil scientists might see while observing a soil profile?
acid pH, low OM content, low levels of soil fertility
What 7 sections of information should be discussed in a soil profile description?
- landform, parent material, relief and drainage
- parent material
- soil profile
- stoniness and rockiness
- erosion and truncation
- vegetation
- land use
What is relief?
the difference in elevation of the land surface forming hills, slopes and valleys
What is landform?
the form or surface expression created by the agency (erosion and deposition) that created the surface.
What is parent material?
the accumulated mineral or organic substances on and in which the soil profile has developed
What are examples of parent material?
colluvial, eolian, alluvial, lacustrine, morainal, saprolitic, volcanic, marine, undifferentiated, anthropogenic
What are different types of classes of surface expression?
hummocky, inclined level, rolling, ridged, steep, terraced, undulating, veneer, apron, blanket, fan
What are slope classes used for?
to indicate the dominant slope within a local landform
What is the rating scale for slope class?
1 (level) - 10 (very steep slope)
What does topography refer to?
the gradient, length, and shape of slopes and their patterns
What is used as a rating scale for Simple Topography - Single Slopes (regular surface)? + slope %
A (depression to level) (0-0.5%) - H (extremely sloping) (60% +)
What is used as a rating scale for Complex Topography - Multiple Slopes (irregular surface)?
a (nearly level) (0-0.5%) - h (very hilly) (60% +)
Once you know the drainage class of a soil, what intelligent decision can you make?
whether or not artificial drainage or irrigation will be required for optimal crop production
What clues should be taken into account to estimate drainage?
vegetation, surface water, height of water table, soil colour, presence of mottles
What should one write about parent material in their soil profile description?
characteristics, source of parent material and manner in which the parent material originated
What is the heart of the soil description?
Soil profile
What should one do as they observe a soil profile in order to write their soil profile description with?
- locate major horizons
2. measure depth + thickness of each horizon
What is not included in depth measurements of a soil profile?
LFH layer
Description of horizon: color - use what chart?
Munsell color chart
When determining color, should the soil be moist or dry?
moist
What is the best method for determining texture?
manipulate and feel a moist sample
What does texture refer to?
size range of soil mineral particles
what does structure refer to?
arrangement of mineral particles into aggregates - size , strength and type or aggregate is important
What does effervescence indicate?
limestone or secondary CaCO3
How can one determine if a soil shows effervescence?
poor dilute HCl to pends, stones, and rocks and see if it foams
What 3 things should be noted about roots in each horizon?
- abundance
- size
- orientation
What does the abundance, size and orientation of roots indicate?
aeration and water content
Stoniness/rockiness of a soil is expressed using what scale?
0 (no stones) - 5 (extremely stony)
0 (no rocks) - 5 (extremely rocky)
What 2 things should be recorded about stones/rocks for a soil sample report?
depth and distribution
What will accelerate erosion of sloping soils?
removal of crop cover
In what 2 ways can erosion be estimated?
- observing the landscape surface
2. determining whether the surface horizon is shallower than normal
What do the type of plants indicate about a soil?
its fertility, drainage, profile type, & type of crop that will grow best
Should present land use be recorded into report?
yes
Mac farm + Arboretum = how many ha?
640 ha
The range in elevation of Mac Campus land ranges from what?
25 m along river to 50 m in Morgan Arboretum
St Bernard: parent material?
glacial till
St Bernard: topography?
undulating (lots of rocks and trees)
St Bernard: vegetation?
deciduous trees, lots of maple (trees that need high fertility/nutrient rich soil)
St Bernard: drainage?
good/well because slope
St Bernard: soil order
Brunisol
St Bernard: what do you notice about the ground cover?
not many leaves - decompose quickly - because of worms
What type of pH do earthworms like?
neutral to slightly basic
St Bernard: soil profile?
Ah – topsoil
Bm – modified
B is not well developed, not much distinction between Bm & C
C –
- no mottling, not much weathering
St Bernard: problems for agriculture?
- low bulk density (very loose soil)
- hard to till b/c very rocky
- land is not flat
St Bernard: advantages for agriculture?
- great for deciduous trees
- good fertility
- good drainage
St Rosalie: parent material
marine clay
St Rosalie: soil order
hummic gleysol
St Rosalie: soil profile
Ah or Ap
(sharp discrimination between A & B horizon)
Bg (mottling)
Cg
St Rosalie: vegetation
grasses, deciduous forests, rice, cranberries
St Rosalie: drainage
imperfect
St Rosalie: management hazard?
water doesn’t go away as fast because of pour drainage
St Rosalie: decomposition rate compared to St Bernard?
Lower decomposition rate - higher OM - high NUTR, slow leaching
St Rosalie: drainage
poor drainage so not much leaching
Uplands: parent material
alluvial (sand over clay)
Uplands: soil order
humoferic podzol
Uplands: soil profile
LFH
Ah (small and unseen)
Ae (white salty layer - extensive leaching)
Bf (precipitation from illuviation - from Ae (Fe & Al))
Uplands: topography
gentle undulating
Uplands: vegetation
coniferous trees
Uplands: biological activity
slow
Uplands: pH - worms?
acidic - no worms
Uplands: drainage - depends on what?
good/fast - depends on width of sand layer (larger = faster)
