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Humus Forms - Group Discussion - Coggle Diagram
Humus Forms - Group Discussion
Mor
most acidic
conifer
Has Fm horizon
Fm horizon mycogenous (Fungi has MOR Fun)
presence of Fungal mycorrhizae
Higher C/N ratio
less soil fauna present
Less is more so must compact the horizons to minimize size
Mull
less acidic
deciduous
Grasslands
Mull has a thin layer and grassland has a thin depth of vegetation
abundant soil fauna and microbial activity
Has Ah horizon
When I drink mulled wine I say "Ah"
Moder
mixture of mor and mull
Loose fragments
Moder is loosely structured matter so it would be a bad idea to motor through it because you would get into a car crash.
Deciduous forests
abundant soil fauna and microbial activity
Has Fz or Fa horizons
More gradual boundary between mineral soil and organic layer
Importance of Humus
Source of nutrients
Natural Mulch
Affects on Soil
Soil Aeration
Soil Temperature
Soil Fertility
Soil Development
Output depends on:
soil aeration
soil chemistry (pH)
soil climate
temperature
moisture
organic matter composition
carbon:nitrogen
Activities of soil organisms
soil animals
physically breakdown organic matter to make more susceptible to breakdown by microorganisms
insects
arachnids
nematodes
annelids
microorganisms
fungi very acid tolerant and able to break down some more or less resistant organic matter (cellulose, lignin) –but fungi are slow
Input depends on
Productivity
Weather
Litterfall
Above ground inputs:
~25% branches
~10-15% stems
50% foliage
~1-2% bark
5 Soil Forming Factors
Vegetation
Microbes
Fungus
Soil Animals
Humans
Humus Horizons
L Horizon
Ln-New, no structural change
Lv-Less recent, still recognizable
F Horizon
Fm
Fz
Fa
H Horizon
Hh
Hz
Hr
O Horizon
Of
Ah Horizon