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5.1 Introduction to soil systems - Coggle Diagram
5.1 Introduction to soil systems
Soil profile
vertical section through a soil, and is divided into horizons
E: subsurface horizon showing depletion of organic matter, clay, iron, and aluminium compounds
B: subsoil horizon showing enrichment of clay material, iron, aluminium, or organic compounds
C: horizons of loosened or unconsolidated material
A: mineral horizon at the surface showing organic
matter enrichment
R: hard bedrock
O: leaf litter
Soil systems
Functions
filter materials added to the soil thereby maintaining water quality
recycling of nutrients takes place in the soil through the breakdown of dead organic matter
contain an important store of relatively accessible fresh water
provide raw materials
medium for plant growth
habitat
Inputs
organic material (e.g. leaf litter)
inorganic matter (from parent material)
precipitation
energy
Outputs
uptake by plants
soil erosion
energy
Storages
nutrients
minerals
organisms
air
organic matter
water
Transfers
biological mixing
leaching
Transformation
Weathering
Nutrient cycling
Decomposition
Soil structure
soil texture: shape and arrangement of individual soil particles (called peds)
Differ by
water-holding capacity
air spaces
drainage
biota
mineral and nutrient content
potential to hold organic matter
Affects primary productivity
Can be identified using a soil triangle
Benefits to plants
supply oxygen
supply mineral nutrients
supply water
protect against adverse changes of temperature and pH
anchorage to roots
Soil sustainability
fertile soil is a non-renewable resource
it cannot be replenished quickly once lost
soil use often exceeds soil formation