Edaphic Factors Affecting Organisms Flashcards
What are edaphic factors?
Edaphic factors relate to soil
Give some examples of edaphic factors that affect organisms.
(6)
Soil pH
Soil type
Organic matter (humus) in the soil
Water content of the soil
Air content of the soil
Mineral content of the soil
What are the two main edaphic factors affecting organisms?
Specific pH values of the soil
Soil type
What are the different pH values a soil can have?
3
Acid soils - pH less than 7
Neutral soils - pH close to 7
Alkaline soils - pH higher than 7
Write a note on how the specific pH value of a soil affects organisms
(4)
Plants and animals are adapted to specific pH values
Acid soils (e.g. bogs) have a pH less than 7 and support bog moss and heather
Neutral soils have pH values close to 7 and are preferred by most plants
Alkaline soils have pH values greater than 7 and are preferred by lime-loving plants, e.g. birdsfoort trefoil and bee orchid
What pH do acid soils have?
A pH less than seven
Give an example of an acidic soil.
Bogs
What plants are supported by acidic environments?
2
Bog moss
Heather
What pH do neutral soils have?
pH less close to seven
What plants are supported by neutral environments?
Neutral soils is preferred by most plants
What pH do alkaline soils have?
Greater than 7
What type of plants prefer alkaline soils?
Lime-loving plants
Give two examples of lime-loving plants that are supported by alkaline soils.
Birdsfoot trefoil
Bee orchid
Write a note on how the type of soil affects organisms
6
Soil type is determines by the size of soil particles
Sandy soils have large soil particles which gives the soil good drainage and air content but sandy soils ma have low mineral and water content
Sandy soils have few earthworms due to the lack of humus
Plants growing in sandy soil such as Marram grass have to have long, deep roots to absorb moisture deep down in the soil
Clay soils have small particles which makes them impermeable to water and air and causes clay soils to be waterlogged easily
Plants do not grow well in clay soils, as the soil is too wet and difficult to penetrate
What are the two main types of soils?
Sandy soil
Clay soil
What determines soil type?
The size of soil particles
Describe the soil particles in sandy soil.
Sandy soils have large soil particles
What is the benefit of sandy soils?
Their large soil particles give sandy soils good drainage and air content
What is the disadvantage of sandy soils?
Sandy soils may have low mineral and water content
What do sandy soils lack?
Humus or dead organic matter
Due to the lack of humus, what is there few of in sandy soils?
There are few earthworms
Why are there few earthworms in sandy soil?
Because there is a lack of humus or dead organic matter
What type of plant grows well in sandy soils?
Marram grass
How has Marram grass adapted to grow in sandy soils?
they have long, deep roots to absorb moisture deep down in the soil
Describe the soil particles in clay soils.
Clay soils have small particles
What is the benefit of small particles in clay soils?
They are impermeable to water and air
What is the disadvantage of small particles in clay soils?
Clay soils become waterlogged easily
What plants grow well in clay soil?
No plant grows well in clay soil
Why do plants not grow well in clay soil?
As the soil is too wet and difficult to penetrate
