Soils Flashcards
What is soil made of? + percentages
Minerals - 45%
Air and water - 50%
Organic matter - 5%
Leaching
Removal of soluble minerals, salts and humus,which are washed downwards through the soil and may accumulate in the subsoil.
Humification
Breakdown or decomposition of plant remains leading to the formation of different types of humus.
Illuviation
Introduction of material to a soil layer.
Eluviation
Removal of materials from a soil layer.
Soil horizon
A layer of soil parallel to the soil crust whose characteristics differ from the horizons above and below.
Soil profile
A vertical cross section of a soil, divided into a number of distinct layers, referred to as horizons.
Regolith
Fragments of rock
Capillary action
Process whereby water and minerals in a solution can be drawn upwards when the rate of evapotranspiration is greater than precipitation.
Parent material
Underlying geological material (bedrock) in which soil horizons for,.
Zonal soil
Mature soils that form under the influence of climate, vegetation, and biota activity.
Intrazonal soils
Soils that do not reflect climactic or vegetation standard influence.
Azonal soil
Immature soils that lack the development of a B horizon
What are the 6 factors affecting soil formation
- Parent material
- Biotic factors
- Climate
- Man
- Relief
- Time
What is in the O horizon
Leaf litter and humus layer
What is in the A horizon
Mix of organic and parent material
What is in the B horizon
Mix of mostly parent material with washed in organic matter
Podzolisation
Leaching of material of iron, aluminium and humus from the surface layers to the lower layers. Causes A horizon to become grey colour and courser in texture. B horizon becomes darker and has a finer texture with an iron pan.
Podzol
Surface - Coniferous vegetation
O horizon - Thin black humus
A horizon - Ash grey colour as minerals are eluviated into B horizon
B horizon - Dark brown - lighter brown
C horizon - Parent material
Distinct layers - not as much biotic activity bc cold + wet climate + acidic
Gley
Surface - Grasses and shrubs
O horizon - Partial decomposition
A horizon - Black with acid humus
B horizon - Blue/ grey clayey mud. Waterlogged, slow decomposition. Angular rock fragments. Unstratified.
C horizon - Permafrost. Solid bedrock, generally shallow soil
Brown earth
Surface - Deciduous vegetation (roots go straight down)
O horizon - Dark brown
A horizon - Light brown
Iron pan between
B horizon - Gradual leaching, iron and aluminium oxides deposited
C horizon - Parent material
