An organic horizon with clear evidence of roots and vegetation
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How would you identify an A master horizon?
An A horizon is mineral rich and so usually dark in colour
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How are E master horizons usualy formed?
Due to percolation of mineral water or acidic leaching, E horizons appear to be bleached (lightly coloured)
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The structure of a soil is associated with the arrangement of Peds (aggregates) and their type...What is the Spheroidal type?
The peds are granular/crumb-like and 1/10mm in size. Characteristic of an A horizon and is perfect for plant growth
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What features do plate-like Ped types have?
They are horizontal and found in all horizons. They can be formed either naturally or artificially (by compaction in agriculture for example).
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What features do bock-like Ped types have and what are the advantages?
The ped shapes are angular or sub-angular blocks 5-50mm in size. This vertical structure is common in B horizons and provides good drainage, aeration and root penetration
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What features do prism-like Ped types have?
This structure type is a vertical structure and has columnar shapes. They are the largest ped types and can have flat rounded or angular tops.
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What is the definition of Bulk Density?
The mass of dry soil of a unit volume
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What is the definition of Particle Density?
The mass per unit volume of solid particles only
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Why do sandy soils have a higher bulk density compared to muddy soils?
Because sandy soils don't contain micro-pores but mud particles do (they have micro-pores inside the clay particles themselves). Sandy soils only contain macropores.
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What general bulk density do Organic soils have and what does this mean?
They have very low densities causing them to shrink when water is removed / they dry out
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Why can high bulk density of a soil be bad?
High bulk density means the soil is dense and so too compact. This restricts plant growth as inhibits root penetration. As well as this, compact soil has poor aeration, and restricts good water/nutrient movement.
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What is a Plough Pan?
A compact hard layer due to compression and compaction, usually from intensive farming/ploughing
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What are the types of Calcareous soils?
Podzols, Spodosols and Mollisols
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What factor largely causes the difference between calcareous soils and Aridisols?
CLIMATE= climate determines the vegetation living on top of the soil and so the movement of minerals and organic matter in the profile. As well as the water movement and content
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Describe how climate impacts Aridisols
Aridisols experience high temperatures thus possible extreme evaporation, therefore causing movement of materials upwards instead of down. This is why Aridisols have a dry texture and are lightly coloured due to the lack of moisture.
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What is the difference between Spodosols and Mollisols?
The original Bedrock and pH differences when these soils are fully formed. Spodosols are more acidic (so a lower pH than mollisols)
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Other cards in this set
Card 2
Front
How would you identify an A master horizon?
Back
An A horizon is mineral rich and so usually dark in colour
Card 3
Front
How are E master horizons usualy formed?
Back
Card 4
Front
The structure of a soil is associated with the arrangement of Peds (aggregates) and their type...What is the Spheroidal type?
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