3 - Biosphere Flashcards
BROWN EARTH: HUMUS LAYER
Thick mull humus layer
BROWN EARTH: A HORIZON
dark brown enriched A horizon
BROWN EARTH: B HORIZON
Lighter brown B horizon
BROWN EARTH: C HORIZON
Weathered parent material
BROWN EARTH:VEGETATION COVER
Deciduous woodland with a layer of undergrowth and long tree roots
BROWN EARTH:SOIL BIOTA
Abundant soil biota
HOW DOES VEGETATION AFFECT BROWN EARTH FORMATION?
deciduous forests provide deep leaf litter and deep roots that recycle nutrients from deep into the soil.
HOW DOES SOIL BIOTA AFFECT BROWN EARTH FORMATION?
abundant soil biota leads to good mixing and aerating of thesoil resulting in poorly defined horizons.
HOW DOES TOPOGRAPHY AFFECT BROWN EARTH FORMATION?
Tend to be found on gentler slopes that allow the formation of thick soils.
HOW DOES CLIMATE AFFECT BROWN EARTH FORMATION?
precipitation slightly exceeds evaporation resulting in a small amount of downward leaching.
HOW DOES HUMIFICATION AFFECT BROWN EARTH FORMATION?
mild/ warmer climate rapidly breaks down organic matter into a mull humus providing a rich dark colour.
HOW DOES TRANSLOCATION AFFECT BROWN EARTH FORMATION?
B horizon is lighter in colour as limited leaching has taken place and an absence of nutrient rich humus.
PODZOL: HUMUS LAYER
Thin black mor humus
PODZOL: A HORIZON
Top stained darker by humus, ash grey eluviated layer
PODZOL: B HORIZON
reddish brown B horizon with iron pan
PODZOL: C HORIZON
Weathered parent material
PODZOL: VEGETATION COVER
coniferous forest, heather moorland with thin undergrowth of mosses and lichens
PODZOL: SOIL BIOTA
lack of soil biota
HOW DOES VEGETATION AFFECT PODZOL FORMATION?
coniferous needles and cones produce an acidic mor humus whilst shallow roots limit absorption of deep leached minerals and nutrient recycling.
HOW DOES SOIL BIOTA AFFECT PODZOL FORMATION?
limited soil biota leads to well defined horizons.
HOW DOES TOPOGRAPHY AFFECT PODZOL FORMATION?
found on steeper slopes that encourages leach through the soil.
HOW DOES HUMIFICATION AFFECT PODZOL FORMATION?
low temperatures cause a slow rate of decomposition.
HOW DOES TRANSLOCATION AFFECT PODZOL FORMATION?
high precipitation leads to the leaching of aluminium and iron oxides. This creates an iron pan between the A/B horizons and may cause waterlogging.
HOW DOES ELUVIATION AND ILLUVIATION AFFECT PODZOL FORMATION?
Eluviation leaves an ash grey A horizon.
Illuviation leads to a reddish brown B horizon
GLEY: HUMUS LAYER
Thin black mor humus
GLEY: A HORIZON
darker brown/grey A horizon (peat may form)
GLEY: B HORIZON
Blue/grey B horizon
GLEY: C HORIZON
Impermeable parent material
GLEY: VEGETATION COVER
shrubs, grasses and rushes with undergrowth of mosses and lichens
GLEY: SOIL BIOTA
Anaerobic conditions so little biota
HOW DOES VEGETATION AFFECT GLEY FORMATION?
limited vegetation produces a thin layer of acidic mor humus and shallow roots limit the recycling of minerals.
HOW DOES SOIL BIOTA AFFECT GLEY FORMATION?
low temperatures mean few organisms can survive whichreduces mixing in the soil causing clearly defined layers.
HOW DOES TOPOGRAPHY AFFECT GLEY FORMATION?
found on flatter ground that results in drainage problems.
HOW DOES WEATHERING AFFECT GLEY FORMATION?
freeze-thaw takes place causing large chunks of angular rock to be brought up to the A and B horizons.
HOW DOES HUMIFICATION AFFECT GLEY FORMATION?
low temperatures cause a slow rate of decomposition.
HOW DOES WATERLOGGING AFFECT GLEY FORMATION?
heavy precipitation and snow melt creates anaerobic conditions and a blue/grey colour due to gleying. If soils dries out in summer mottling occurs due to small oxygen pockets and the re-oxygenation of iron.
