11/30/2017

1

Chapter 18

Soils

Study of soils called pedology; deals with:

origin (genesis)

distribution

description

classification

Why are Soils Geography?

Geographers are interested soils because

their distribution is linked to

climate

vegetation

land use patterns

economic activity

& many other physical and cultural attributes

11/30/2017

2

What is a Soil?

A naturally occurring body consisting of a

mixture of:

weathered rock material (i.e. minerals)

organic matter (humus)

water

air

• Geologic processes -> Sediments

• Pedogenic processes -> Soils

• Develop on stable surfaces as a

result of the interaction of:

• climate

• biotic organisms

• relief (slope)

• and parent material

• over time

• anthropogenic influences

Soil Formation Factors

• Process of soil formation is

called pedogenesis and

involves:

• transformations – weathering

• additions - horizontal movement

• losses - horizontal movement

• translocations

• vertical movement

• illuviation & elluviation

Soil Formation Factors

11/30/2017

3

Soil Profiles and Soil Horizons• Formation typically results in distinct layers or

horizons differ in terms of:

• colour

• texture

• structure

• consistence

• porosity

• mineral constituents

• and chemical composition

• Sequence of horizons from surface to unaltered

material makes up soil profile

Soil Profiles and Soil Horizons

Soil Properties

Soil Colour

Soil Texture

Soil Structure

Soil Consistence

Soil Porosity

Soil Moisture

Soil Chemistry

Soil Acidity and Alkalinity

11/30/2017

4

Soil Colour

What is the size of particles

Texture

Size mm

Sand very fine to

very coarse

0.063

2.00

Silt 0.002-0.063

Clay < 0.002

Soil

Texture

11/30/2017

5

Soil StructureSoil

Structure

Soil

Chemistry

Soil Acidity and Alkalinity

11/30/2017

6

Soil Classification

The Canadian System of Soil Classification

Categories of Classification in the CSSC

Soil Horizons in the CSSC

The 10 Soil Orders of the CSSC

The Canadian System of Soil

Classification (CSSC)

Profile Category Levels

Order

Great Group

Subgroup

Family

Series

Manitoba soilsFactor Chernozem Luvisol Gleysol Regosol

Native

vegetation

Grassland Forest Moisture-loving

grasses

Limited vegetative

growth

Moisture

regime

Normal Normal Wet Variable to dry

Formative

processes

Vegetation

puts bulk of

biomass

production

below ground

Vegetation

puts bulk of

biomass

production

above ground

Moist or saturated

conditions affect

decomposition

process

Relatively young

soils not fully

stabilized by

vegetation

Distinguishing

features

Thick topsoil

horizon (Ah)

Strongly

leached

horizon (Ae)

Dull, blue-grey

colours and

mottles (Bg or Cg)

Little soil profile

development due to

droughtness,

erosion, or

deposition

Typical

landscape

position

Midslope Upper slopes Depressions Upper slopes

11/30/2017

7

CSSC Soil Horizon Designations

Copyright © 2013 Pearson Canada Inc.

Photo by USDA NRCS

11/30/2017

8

Copyright © 2013 Pearson Canada Inc.

CSSC Soil Horizon Designations

Soils Phases

1.Degree of Erosion

2.Slope Class

3.Stoniness

4.Degree of Salinity

Parent Material modes of disposition

Mode of

Disposition

Description Examples

Till Glacier deposited,

Stony mixed material

SW and

Interlake

Lacustrine Lake Deposited

material well sorted

Red River

Valley

Fluvial River deposited

material

Assiniboine

and Pembina

Eolian Wind Deposited Spruce woods

Organic peat North Interlake

11/30/2017

9

Copyright © 2013 Pearson Canada Inc.

CSSC Soil Horizon Designations

CSSC Organic Soil Horizons

The Ten Soil Orders of the CSSC

Brunisolic Order

Chernozemic Order

Cryosolic Order

Gleysolic Order

Luvisolic Order

Organic Order

Podzolic Order

Regosolic Order

Solonetzic Order

Vertisolic Order

11/30/2017

10

Soils of

Canada