Soils Flashcards
What is soil made up of
Mineral matter
Air
Water
Humus
Living organisms
Humus
A gel like substance made of plant litir and decayed animals.
O horizon
The layer of soil visible. Plant litter falls here to decay which provides humus
A horizon
Most fertile layer of soil. Plant roots are found. Dark in colour, mist humus &living organisms
B horizon
Lighter in colour bc of less humus. Higher number of stones are found here
C horizon
A mixture of solid rock and broken rock. The remains of the parent rock from when the soil was formed
3 things soil formation is influenced by
Time
Landscape/ relief
Vegetation
Landscape/ relief
Soils in upland areas are thin and poorly drained bc of heavy rain
Soils in lowland areas are more fertile, well drained and rich in humus
Vegetation
Vegetation creates plan litir (humus) which makes soil fertile
Deciduous trees=more plant litir
Coniferous trees= less plant litir
4 main soil types in ireland
Brown earth soils
Podzol soils
Gley soils
Peaty soils
Influence of soil on vegetation
Depth
Acidity
Drainage
Depth
Deep fertile soils have a high nutrient content which supports lots of vegetation
Shallow infertile soils are usually limited to coniferous forests
Acidity
Many plants do not grow in areas w acidic soil. Farmers spread lime on the soil to make it more fertile and less acidic bc of this
Drainage
Sandy soils- well drained & supports lots if vegetation
Clay soils- waterlogged & doesn’t support much vegetation
Influence of vegetation on soil
Plant littir
Soil erosin
Leaching
Plant littir (influence of vegetation on soil)
Vegetation provides plant littir to make humus
Soil erosin (influence of vegetation on woil)
Vegetation binds the soil- protects it from soil erosin
If there is no Vegetation soil erosin occurs
Leaching (influence of vegetation on soil)
Vegetation protects soil from heavy rainfall.
Reduces the effects of leaching
Causes of soil erosin
Deforestation
Overgrazing
Overcropping
Case study
Desertification in the sahel (borders Sahara desert)
Causes of desertification- Climate Change
Less rain in the sahel
Results in drought and famine
Vegetation has died and soil is less fertile
Causes of desertification- Human Activity
Soil erosin occurring due to cutting down of trees
Increased herd numbers=overgrazing
Farmers growing cash crops (coffee)= not suitable to region
Results of desertification
Soil no longer fertile, not good for agriculture- crop failure and animals dying
Grassland has been changed into desert- forcing migration
Famine.
