SOIL NCES: 6.E.2.3 & 2.4 Kim Lachler Updated 11/11/14

SOILSOIL

NCES: 6.E.2.3 & 2.4Kim Lachler

Updated 11/11/14

Soil CompositionSoil Composition

Consists of:Consists of: Weathered rockWeathered rock Decayed organic matterDecayed organic matter Mineral fragmentsMineral fragments WaterWater AirAir


Organic MatterOrganic Matter

Majority of it is dead vegetationMajority of it is dead vegetation

Rest is dead animals and micro-organismsRest is dead animals and micro-organisms

Humus Humus is dark material made from organic matteris dark material made from organic matter

provides nutrients for plantsprovides nutrients for plants


There are spaces There are spaces between the particles of between the particles of soilsoil

When the soil is dry they When the soil is dry they are filled with airare filled with air

When the soil is wet they When the soil is wet they are filled with waterare filled with water

Soil TextureSoil Texture

The size of the particles of the rocks and minerals The size of the particles of the rocks and minerals makes up the texture.makes up the texture. Clay Clay Silt Silt Sand Sand Gravel Gravel Rock Rock

Clays feel sticky.Clays feel sticky. Silt feels smooth. Silt feels smooth. Sand feels gritty.Sand feels gritty.

Loam soilLoam soil a soil with roughly equal proportions of sand, silt, and clay.a soil with roughly equal proportions of sand, silt, and clay.

Soil ProfileSoil Profile

Soil Profile Soil Profile Is made up of all the Is made up of all the

layers of soillayers of soil

HorizonsHorizons What the layers of soil What the layers of soil

are calledare called

Most soil profiles have Most soil profiles have 3 horizons3 horizons


A horizon A horizon Also known as topsoilAlso known as topsoil Top layerTop layer Many be covered with litter (leaves, twigs, etc)Many be covered with litter (leaves, twigs, etc)


B horizonB horizon Middle layerMiddle layer Lighter in colorLighter in color Less fertile (less nutrients)Less fertile (less nutrients) Has the most leached materialHas the most leached material

Leaching – Leaching –

when minerals are dissolved in water in the A horizon and when minerals are dissolved in water in the A horizon and carried down by the water to the B horizon.carried down by the water to the B horizon.


C HorizonC Horizon Bottom horizonBottom horizon Made from weathered rockMade from weathered rock Contains little leaching or organic matterContains little leaching or organic matter

What is under the C Horizon?What is under the C Horizon? Bed rock Bed rock

Soil FormationSoil Formation

There are 5 factors that There are 5 factors that affect soil formationaffect soil formation ClimateClimate Parent materialParent material VegetationVegetation SlopeSlope TimeTime


ClimateClimate Dry climates have less Dry climates have less

organic matter thus organic matter thus thinner soils than wetter thinner soils than wetter climatesclimates

Cold climates also have Cold climates also have less organic matter thus less organic matter thus thinner soils the thinner soils the temperate climatestemperate climates


VegetationVegetation

Areas with lots of vegetation like parries and forest Areas with lots of vegetation like parries and forest have more organic matter, therefore richer top soilshave more organic matter, therefore richer top soils

Richer top soils encourage more vegetation growthRicher top soils encourage more vegetation growth

so which came first?so which came first?


Parent rock Parent rock

The minerals that make The minerals that make up the bedrock is what up the bedrock is what determines the minerals determines the minerals in the soil.in the soil.

This will affect the type This will affect the type of vegetationof vegetation

Soil FormationSoil Formation SlopeSlope

Since gravity pulls things down hillSince gravity pulls things down hill

Soils near the top of a slope are thinnerSoils near the top of a slope are thinner

Soils near the bottom of a slope are thickerSoils near the bottom of a slope are thicker


TimeTime The longer the bed rock has been weathered the The longer the bed rock has been weathered the

more minerals will be in the soil.more minerals will be in the soil.

BibliographyBibliography GlencoeGlencoe

Google images, soil, Google images, soil, www.googleimages.comwww.googleimages.com, accessed 11/21/2011, accessed 11/21/2011 Google images, humus soil, Google images, humus soil, www.googleimages.comwww.googleimages.com, accessed 11/21/2011, accessed 11/21/2011 Google images, leaching soil, Google images, leaching soil, www.googleimages.comwww.googleimages.com, accessed 11/21/2011, accessed 11/21/2011 Colorado state University Extension, CMG garden notes, Colorado state University Extension, CMG garden notes, http://www.ext.colostate.edu/mg/gardennotes/214.htmlhttp://www.ext.colostate.edu/mg/gardennotes/214.html, accessed 11/11/14, accessed 11/11/14

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SOIL NCES: 6.E.2.3 & 2.4 Kim Lachler Updated 11/11/14