soil formation and classification flashcards

What is the difference between Of and Oh organic horizon suffixes?

Of represents fibric material with very little decomposition, whereas Oh represents humic material that is highly decomposed.

What parent material and environmental conditions favor Podzolic soil formation?

Acidic parent material (e.g., igneous rock on the Canadian Shield or PEI), sufficient rainfall, and coniferous/forest vegetation.

What defines an end moraine?

A positive topographic feature formed at the farthest point of glacial advance (terminus), composed of unsorted material dropped as the glacier melts.

How does topography influence soil formation across a landscape?

Different topographic positions redistribute water, altering drainage patterns, leaching, and organic material accumulation.

What diagnostic horizons and visual cues identify a Gleysolic soil?

Presence of a Bg or Cg horizon within 50cm of the surface, characterized by a dull bluish-grey color.

Why are Solonetzic soils unfavorable for crop production?

High salt levels disrupt water uptake via osmotic gradient problems and break down soil structure/aggregation.

What causes the color difference between Black Chernozems and Brown Chernozems?

Black Chernozems contain higher amounts of accumulated organic material than Brown Chernozems due to higher moisture and biomass addition.

What is the highest and coarsest level of classification in the Canadian System of Soil Classification?

Soil Order

What is the primary ecological setting and key diagnostic feature of Chernozemic soils?

Grasslands of the southern prairies, characterized by a deep, dark, organic-rich surface $Ah$ or $Ap$ horizon.

Why does organic material accumulate to form Organic soils instead of decomposing?

Saturated waterlogged conditions create anaerobic (low-oxygen) environments that drastically slow microbial decomposition rates.

How does glaciation affect soil parent material and topography?

It grinds up, remixes, and redistributes local bedrock, altering both soil texture and physical landscape topography.

What key horizon designations indicate a Solonetzic soil?

Presence of a $Bn$ or $Bnt$ horizon (indicating high sodium accumulation).

What type of parent material is typically associated with Luvisols?

Calcareous parent material (indicated by a underlying Ck horizon).

What diagnostic horizon indicates a Brunisolic soil?

A Bm horizon (showing minimal to moderate material translocation/transformation).

How does the shape of a kame compare to that of a drumlin?

A kame is pointier and conical, whereas a drumlin is an elongated teardrop shape.

What default soil order exists when a profile meets none of the diagnostic criteria for other Canadian orders?

Regosolic order

Why does a lower soil pH increase the formation of a Podzolic $Bf$ horizon?

As pH drops, the chemical mobility of iron ($Fe$) and aluminum ($Al$) metals greatly increases, allowing water to leach them into the $B$ horizon.

What is a kame and what shape does it take in the landscape?

A conical hill formed when running water deposits sediment down ice fissures, leaving a steep sediment column after the ice retreats.

Which soil formation factor is the primary driver of Gleysolic soil occurrence?

Topography, as low slope positions collect surface runoff and cause persistent waterlogging.

How does the bedrock parent material of Northern Ontario differ from that of Southern Ontario?

Northern Ontario is dominated by ancient igneous bedrock, whereas Southern Ontario bedrock consists of ancient shallow sea deposits (calcareous coral/limestone).

What signature horizon defines the Luvisolic soil order?

A $Bt$ horizon, indicating an accumulation of illuvial clay translocated down from upper horizons.

What glaciofluvial landform is produced by fast, highly turbulent meltwater leaving coarse material behind?

Spillway

How does a drumlin form?

Advancing glacial ice pushes back over a recessional moraine or obstruction, heaving over it and streamlining it into a teardrop shape.

What four basic pedological processes lead to the formation of soil horizons in a soil profile?

Additions, losses, transfers, and transformations.

How can you determine the direction of glacial ice movement by examining a drumlin?

The steep side of the teardrop-shaped hill points toward the direction from which the glacier approached.

What is the primary defining profile feature of a Regosolic soil?

Lack of a developed $B$ horizon due to minimal soil development.

How do Gleysolic soils differ from Organic soils in terms of drainage and organic content?

Gleysols are poorly drained mineral soils, whereas Organic soils are even more severely waterlogged, accumulating purely organic material.

What key diagnostic horizons identify a Podzolic soil?

A $Bf$, $Bhf$, or $Bh$ horizon that is at least $10\text{ cm}$ thick, enriched with translocated iron and aluminum.

What diagnostic criterion immediately classifies a soil into the Cryosolic order?

The presence of permafrost (indicated by a $z$ horizon designation).

How can earthworm channels help determine clay movement in Luvisolic soils?

the channels act as biopores through which translocated clay physically moves downward to form the Bt horizon.

What is the hierarchy of soil descriptions in the Canadian System of Soil Classification, from broadest to most specific?

Order $\rightarrow$ Great Group $\rightarrow$ Subgroup $\rightarrow$ Family $\rightarrow$ Series.

How does a Brunisolic soil relate chronologically to a Regosolic soil?

A Brunisol represents the next stage of development after a Regosol as time allows weathering and material movement to begin forming a $B$ horizon.

What soil textures dominate former glacial lake bed areas?

Silt and clay textures (glaciolacustrine deposits).

Despite making up a small proportion of Canadian land area, why are Chernozemic soils vital?

They possess high natural organic matter and fertility, making them Canada's most productive agricultural soils.

What is the general temporal pathway of soil profile development in Southern Ontario?

Regosol (undeveloped) $\rightarrow$ Brunisol (weakly developed $Bm$) $\rightarrow$ Luvisol (fully developed $Bt$).

What is the typical texture and sorting state of soil parent material deposited in a moraine?

Unsorted loam material containing a mixture of sand, silt, clay, gravel, and boulders.

What defines an Organic soil order in the Canadian system?

Soils composed almost entirely of organic materials accumulated in wet, poorly drained environments like marshes and bogs.

Approximately how long ago did glaciers retreat from most of Canada?

12,000 to 15,000 years ago.

How does the direction of soil formation differ between mineral soils and organic soils like Holland marsh soils?

Mineral soils form from the top down, whereas organic marsh soils form from the bottom up due to slow decomposition.

What is an esker and how does it form?

A narrow, winding ridge of almost pure sand formed by fast-moving meltwater flowing in tunnels beneath a glacier.

What condition causes high salt buildup and quick clays in the historical Champlain Sea region?

Salts had nowhere to wash out, leading to sodium accumulation that disperses clay particles and destabilizes soil.

Why did glacial ice invade low topographic areas like the St. Lawrence River valley first?

Glaciers move primarily under the force of gravity, naturally flowing into and filling the lowest topographic points first.

Why are Podzolic soils generally challenging for agricultural crop production?

They are highly acidic in nature, which creates nutrient availability issues and toxicity for many crops.

What are the five fundamental soil formation factors?

Parent material (geological materials), climate, organisms, topography, and time.

What topographic and climatic conditions promote Solonetzic soil formation?

A dry climate combined with low topographic positions where salt-bearing water drains laterally and evaporates, pulling salts upward.

What environmental conditions are required for Vertisolic soils to form?

High clay content of shrinking/swelling type and a dry climate to induce persistent cracking.

What diagnostic structural feature characterizes Vertisolic soils?

Presence of deep, persistent vertical surface cracks and slickenside horizons within $1\text{ m}$ of the surface.

Why does fast-moving glacial meltwater deposit sand flatlands before reaching glacial lakes?

As turbulent streams widen and slow down, heavier particles like sand drop out rapidly, leaving flat sandy deposits.

What chemical transformation produces the dull bluish-grey color in Gleysols?

Anaerobic, waterlogged conditions force soil microbes to use iron as an electron acceptor, reducing oxidized ferric iron to reduced ferrous iron.

How does the topography of a ground moraine differ from that of an end moraine?

Ground moraines have a flatter, more subdued topography because the ice melted faster than it was advancing.

In which regions of Canada are Cryosolic soils found?

Northern Canada (absent in Southern Ontario).

Which soil formation factor is the main limitation in Regosolic soil development?

Time (insufficient time has passed, or frequent disturbance like flooding resets profile development).

Along a hill slope in Southern Ontario, what soil orders are typically expected at the well-drained top versus the wet bottom?

Luvisols dominate well-drained upper hills, while Gleysols or Organic soils occur in poorly drained depressions at the base.

What are Lacustrine deposits?

They are defined as sediments that accumulate and settle in the bottom of lake environments, more silt and clay, and not too much fine sand

What are delta deposits?

sandy because deltas are where rivers empty into slow moving or still bodies of water (like oceans.) Sandy material can be deeper or clay in the top, or vise versa.

What are drumlin deposits?

No sorting by water still. Since parent material is glacial till, drumlin deposits consist of unsorted sediments, characterized by a mix of clay, silt, sand, and gravel.

What are end morraine deposits

It would be a mixture of all materials and no sorting. It would dump out a lot of loam material with complex topography.