Soil Physical Geography

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Great civilizations began because of farming ... good soil and fresh water is needed for farmingAncient Egyptian and Mesopotamian societies are great examples

Egyptian civilization grew up around the fertile Nile River and its DeltaThe Sahara Desert, which has poor sandy soil, doesnt have very many people living there because the people cant grow things in the soil.90% of Egypts population lives with 20 km of the Nile River or its delta.3

Toronto is Canada's economic, political and cultural powerhouse, it started as a farming centre51% of Canada's good farmland can be seen from the top of the CN tower; most of it is paved or built on4Do We Really Need Soil?Lets Dig Up the Facts!

Soil Contains the Minerals All Living Things Need!

We Use Soil to Grow Food!

Many Animals and Microscopic Creatures Live in the Soil!

Soil Helps Soak Up Rainwater So We Dont Have Flooding!

SoilSoil is made up of 4 main parts:MineralsOrganic and Bacterial materialsMoistureAir

Think -MOMA MineralsEx. calcium, phosphorus, potassium, etc..Comes from parent material (usually rock) or loose material deposited from a glacierMinerals become part of the soil when rock is broken down by weathering

Organic and Bacterial MaterialDead plants and animals are decomposed by bacteria in soil, nutrients are released to form humusHumus provides nutrients and moisture to plants and gives soil its dark colour.What does Humus look like?

MoistureWater dissolves nutrients in soil allowing plants to take them up through their rootsWater is also needed in the processes that weathers rock and decays organic materialAirAir in soil is created by high humus levels (loose, decaying material allows for many air pockets), worms, insects and small animalsPlants need air around rootsTypical Soil Profile

SOIL PROFILE:A cross section of soil from the surface to the bedrock.O organic material dying material (plants and animals) things in the process of breaking down

A horizon topsoil rich in organic materials; takes hundreds of years to produce; thin layerB horizon sub-soil; mainly inorganic material (broken up rock) with some organic materialC horizon parent material broken pieces of rock and/or solid rock17

O Horizon: Organic MaterialWhat does Topsoil look like?

A HorizonWhat does Subsoil look like?

B HorizonWhat does the Parent Material look like?

C Horizon

What happens if the soil is too wet?Leaching- the excess water dissolves nutrients and carries them away (downward), making it difficult for plant roots to reach nutrientsLeached soil has poor, usually thin topsoil layer

Much of Canada is covered with Wet-Climate soil

What if the soil is too dry?Calcification- there is an upward movement of waterAs water in the top soil evaporates, water from below is drawn up to replace itAs water evaporates, it leaves behind mineralsTopsoil is thick and rich in mineralsIf soil is very dry, the amount of minerals left can create a layer that is poisonous to plants

Types of SoilLuvisolicComposed of broken down sedimentary rockHigh clay contentCan be very wet

PodzolicBroken down igneous rock which turns to sandSands provide more rapid drainageHigh mineral content

BrunisolicBroken down igneous rock which turns to sandSand provides more rapid drainageHigh mineral content

OrganicHigh amount of humusSands provide more rapid drainageHigh mineral content

ChernozemicHigh amount of humusSandy or clay baseModerate mineral content (mostly in the upper horizons)Typically dry at lower horizons

VertisolicHeavy clay based soilHigh water retentionModerate mineral content (concentrated at the upper horizons)Can also dry out, crack and shift easily

CryosolicPermafrostVery thinCan be saturated with water in the spring due to top layer thawing

Soil Regions

Tundra SoilsType of Soil Luvisolic, Podzolic, Burnisolic, CryosolicMain CharacteristicsThin and poorly developedIssues allowing/preventing the development of the soilPermafrost- frozen ground inhibits plant growth/inhibits topsoil developmentWet ClimateType of Soil Luvisolic, Podzolic, Brunisolic, OrganicMain CharacteristicsThin leached soils across the Canadian SheildGrey brown Podzolic SoilIssues allowing/preventing the development of the soilNeeds additional fertilizer due to leaching

Dry ClimateType of Soil Vertisolic, Chernozemic, some LuvisolicMain CharacteristicsSandy or clay basedHigh water retentionIssues allowing/preventing the development of the soilLimited by lack of rain

Complex SoilsType of Soil Luvisolic, Podzolic, BrunisolicMain CharacteristicsVaries on locationIssues allowing/preventing the development of the soilVaries due to location