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23 Cards in this Set
- Front
- Back
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What is the percentage composition of soil? |
25% water 25% air 45% mineral 5% Organic matter |
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What is the biggest to smallest soil particles |
Sand-to-silt-to-clay |
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What is good about sand in soil? |
-It's the largest particle so the pore spaces between them are large, this allows good drainage.
-However in low rainfall sandy soils are more susceptible to drought. In times of high rainfall sandy soils are less likely to suffer from waterlogging
-Sandy soils heat up quickly
-Sandy soils do not contribute to soil fertility |
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What is so good about clay in soil? |
-Clay is the smallest particle and so the pores spaces between in particles are small makes it difficult for water to pass through soil, this means poor drainage -In times of low rainfall Clay soils are less likely to suffer from . In times of high rainfall Clay soils are more likely to suffer from waterlogging -It does not warm up easily -Does contribute to soil fertility |
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Sand |
Particle size:Large Pore size:Large Drainage:Good Aeration:Good Low rainfall:Prone to drought High rainfall:Resistant to waterlogging Fertility: Doesn't contribute |
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Clay |
Particle size: SmallPore size: SmallDrainage: PoorAeration: PoorLow rainfall: Resistant to drought High rainfall: Prone to waterlogging Fertility: Does contribute |
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Soil texture |
Soil texture: The proportions of sand silt and clay particles in soil Loam: A soil with roughly equal amounts Soil texture influences the Aeration, drainage, available water and nutrients Can be determined by the feel method, sieve method, or sedimentation method |
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How to use a soil triangle |
For clay draw parallel to sand For sand draw parallel to silt For silt draw parallel to clay |
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Sandy soils |
Drainage: Good Aeration: Good Low rainfall: Prone to drought High rainfall: Resistant to waterlogging Temperature: Warms up quickly Fertility: Low Fertility |
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Loam soils |
Drainage: Good Aeration: GoodLow rainfall: Not Prone to drought High rainfall: Not Prone to waterlogging Temperature: Will warm upFertility: Good fertility |
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Clay soils |
Drainage: PoorAeration: Poor Low rainfall: Resistant to drought High rainfall: Prone to waterlogging Temperature: Does not warm up quickly Fertility: High fertility |
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Soil structure |
-The arrangement of particles (Sand, silt and clay) in soil -Soil come together and aggregates (clumps) -Between the particles in aggregates are micropores -Between the aggregates are micropores -Cementation is the binding of soil particles in aggregates |
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What does soil structure effect? |
-Directly affects the movement of water and air in soil -This affects the soil temperature -The moisture, air and temperature affects the organisms in the soil (ex plant roots and earthworms Overall effects: Crop yield, pollution and fertiliser efficency |
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Soil compaction |
-Is the squashing together of soil aggregates -Reduces the number of macropores -Can be caused by machinery and livestock on wet land -Reduces amount of air in soil and restricts movement of water which leads to waterlogging |
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Soil air |
-Roots need to be able to respire and so need oxygen that exists in the pores between particles -Energy from respiration in roots is used to absorb nutrients by active transport -When waterlogging occurs there is no air -Air warms up faster than water and so soils with large pore spaces (better drainage) warm up quicker in the spring |
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What is soil water needed for? |
Soil water is needed for the germination of seeds, photosynthesis and keep plants turgid |
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What is gravitational water and capillary water? |
Gravitational water: Moves Down through the soil pores with gravity, temporarily available to plants before draining awayCapillary water: Moves up through the soil by Capillary action. Water held in small pores is unavailable but larger pores is available Gravitational water: Moves Down through the soil pores with gravity, temporarily available to plants before draining awayCapillary water: Moves up through the soil by Capillary action. Water held in small pores is unavailable but larger pores is available Capillary water: Moves up through the soil by Capillary action. Water held in small pores is unavailable but larger pores is available |
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What is field capacity? |
The volume of water in the soil after the gravitational water has drained away |
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What is permanent wilting point? |
The minimum amount of water in a soil that is required to prevent a plant from wilting, if the soil water decreases more than this the plant will wilt |
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What is available water capacity? |
The Water that is available for uptake by plants To find it you subtract field capacity by permanent wilting point |
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How does soil colour influence soil temperature? |
Soil colour depends on minerals and organic matter (if a dark colour it is rich in organic matter) That means the soil warms up faster which means the soil will have larger proportions of air which will then effect the soil temperature and the rate of reaction and the crop will grow faster |
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What is soil erosion? |
Soil erosion is the wearing away of the top layer of soil Usually caused by rain or wind Rain: rain loosens material causing particles to separate then washed away Wind: picks up and moves small particles from the top layer of soil |
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What can prevent soil erosion |
Vegetation binds the soil together and helps to prevent soil erosion and so catch crops can be used to cover fallow soil |
