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Soils ChapterSoils Chapter

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Today’s key termsToday’s key terms

• Soil

• Mineral matter

• Air

• Water

• Living organisms

• Humus

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What is soilWhat is soil

• Soil is the thin layer of loose material on the earth’s surface.

• Plants grow in it.

• It is a natural resource.

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What is soil made up ofWhat is soil made up of

• Mineral matter

• Air

• Water


• Humus

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Mineral matterMineral matter

• This is the largest ingredient in the make up of soil.

• Mineral matter is the remains of rocks.

• It looks like gravel and silt

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AirAir

• Air is in the space between the soil particles.

• Air is important for the growth of roots

• It is also important in the formation of humus.

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WaterWater

• Water is important as it contains dissolved minerals.

• These minerals provide plants with important nutrients that are required to grow.

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Living organismsLiving organisms

• These included•Earthworms•Slugs•Woodlice•Insects•Bacteria •Fungi

• The bacteria and fungi in the soil helps to break down dead plants to form Humus

• This Humus increases the fertility of the soil

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HumusHumus

• Humus is the decayed creatures, plants and litter.

• Humus provides the soil with nutrients.

• Humus increases the fertility of the soil

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Soil formationSoil formation

• Soil formation can be influenced different factors and they included

• Climate• Parent Rock• Vegetation• Micro-organisms• Time• People

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Soil formationSoil formation

Climate

Parent Rock Vegetation

Micro-organisms

SoilTime People

All Mix to form

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ClimateClimate

• Climate affects the following

• amount of rainfall • The temperature

• All of this affects the amount of vegetation

• Back

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Parent RockParent Rock

• Climate influences the amount of erosion/weathering that occurs to rock in a region

• This influences the amount of mineral matter that is present in the soil.

• Back

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VegetationVegetation

• Influenced by the climate

• The type of Vegetation

• The amount of Vegetation

• Back

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Micro-organismsMicro-organisms

• These Micro-organisms break down the vegetation

• The amount of vegetation dictates the amount of humus in the soil

• Back

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TimeTime

• The amount of time soils is allowed form dictates the type of soil that forms.

• It takes approx 400 years for 1cm of soil to form.

• Back

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PeoplePeople

• People can alter the formation of soil

1. Irrigation, drainage or fertilizing all make the soil more fertile

OR

2. Overuse make the soil les fertile.

Back

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HomeworkHomework

• Update all your notes

and

• Question 1 on page 183

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Today’s key terms revisedToday’s key terms revised

• Soil

• Mineral matter

• Air

• Water


• Humus

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Today’s Key TermsToday’s Key Terms

• Soil profile• Horizon

• Leaching• Hardpan

• Brown Soils

• Podzol Soils

• Peaty soils

• Gley soils

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Last classes terms revisedLast classes terms revised

• Soil

• Mineral matter

• Air

• Water


• Humus

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Soil profileSoil profile

• Soil is made up of different layers

• Each layer is called a horizon

• Each layer is labelled with a letter

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Soil profile of a litter plantSoil profile of a litter plant

• Horizon A • This is the upper layer

• It is made of topsoil

• It has a high Humus content

• It is dark in colour

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• Horizon B• Found underneath horizon A

• It is called a subsoil

• Less Humus more stones

• Lighter colour

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• Horizon C• Is the layer of parent rock

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LeachingLeaching

• This is the washing of nutrients from one horizon to the other.

• This can cause the loss of fertility in horizon A

• If leaching is severe it can result in hardpan

• This is grey in colour and is impermeable.

• This can result in a field been very wet as water cannot soak into the ground.

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Irish SoilIrish Soil

• There are four main types of Irish soils they include

• Brown Soils

• Podzol Soils

• Peaty soils

• Gley soils

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Brown SoilsBrown Soils

• Found in area where deciduous trees used to be.

• Horizon A is rich in humus

• Horizon B has a blend of horizon A due to worm action

• Horizon C is made of bedrock

• This is a very fertile soil

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Podzol SoilsPodzol Soils

• Found in area where coniferous trees are found.

• These are mainly found in cold climates

• Horizon A has low levels of humus

• Cold weather has limited worm activity

• Between horizon A and horizon B a hardpan may develop.

• Horizon C is made of bedrock

• This is a very infertile soil

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Gley SoilsGley Soils

• Develop in areas where the bedrock is impermeable.

• Or there is a band of hardpan above the parent rock bed

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Peaty soilsPeaty soils

• Develop in high upland areas.

• Areas with high rainfall

• Results in water logged land

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Today’s Key termsToday’s Key terms

• Tropical red soil• Climate• Chemical weathering• Iron oxide Leaching• Infertile

• dd

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Last classes Key TermsLast classes Key Terms

• Soil profile• Horizon

• Leaching• Hardpan

• Brown Soils

• Podzol Soils

• Peaty soils

• Gley soils

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Tropical red soilsTropical red soils

• Found in areas that have tropical or equatorial climates.

• Formation influenced by hot, wet climatic conditions.

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Formation• The formation/make up of this soil is different to

Irish soils.

• Continuous leaf fall

• Therefore thick layer of litter

• This is broken down due to• Mirco-organisms• Hot, wet climatic conditions.

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Formation• The acid from the humus assists the weathering

to the parent rock

• The erosion is also aoded by the high temperatures

• The weathering of the rocks breaks down the iron oxide in the soil.

• This gives it a reddish colour.

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Is the soil FERTILE OR INFERTILE• Normal conditions very fertile due to continuous

leaf fall.

HOWEVER

• When the forest are cut away the soil suffers from leaching due to heavy rainfall.

• This leads to the soil becoming infertile.

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Natural vegetation and soilNatural vegetation and soil

• Soil influences vegetation• The soils fertility dictates how much the vegetation

grows

• Vegetation influences soil• The vegetation dictates the amount of humus in the

soil.

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Soils influences on vegetationSoils influences on vegetation

• Fertile soil• The more fertile the soil the more it can support strong

growth.

• Infertile soil• Lack of nutrients can limit the amount of growth that soil

can support. Typical vegetation would include coniferous trees.

• Soil depth• Trees such as oak and beech need a large depth of soil

because of there deep roots and there need for nutrients.

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Vegetations influence on soilVegetations influence on soil

• Humus role• Binds soil• Nourish soil• Influences the colour of horizon A

• Vegetation reduces the effect of leaching• Roots absorb the leached nutrients

• Vegetation reduces soil erosion• Roots bind the soil• Roots absorbs some of the water content in the soil.