1. Soil profiles, characteristics and profiles.
Podzol.
Brown Earth
Gley

2. Podzolization This is an intense form of leaching.
Occurs when rainfall is greater than precipitation.
The main substances leached out of the soil include iron, aluminium and humus compounds.

3. Describing Podzols
LOCATION – found in Northern coniferous forests OR upland moorland areas.
CLIMATE – cold wet climates where precipitation exceeds evaporation.
DESCRIPTION – Thin top layer, Ao Horizon, of needles and cones decomposing to form a raw acidic humus (mor).
The A horizon has a ash coloured tint to it composed of insoluble silicates.
The B horizon has a reddish tint to and an iron pan may form here.

4. Explaining the formation of Podzol.
The soil forming process is very slow because of the cold climate.
Ao Horizon - Thin humus layer because of little humification:-
Trees have needles not leaves.
Trees do not shed their needles every year.
Needles break down very slowly.
Few biota live in this cold climate.
Leaching occurs due to heavy rainfall and melt water.

5. Continued….
A Horizon - Zone of Eluviation where humus, iron and clay are leached through the A Horizon.
B Horizon - Zone of Illuviation where clay, humus and iron are deposited and accumulated. Giving the red tint to the horizon.
Iron pan forms where iron is re-deposited between the A and B horizons.
The soil is sometimes waterlogged because the iron pan prevents further downward movement of water.
C Horizon – forms from a range of parent material
There is very little mixing of the horizons because of lack of living organisims – BIOTA.

6. Describing Brown Earth Forest Soils.
LOCATION – deciduous forests of Europe, Russia and North America.
CLIMATE – mild winters and summers, quite wet all year. Temperate maritime.
DESCRIPTION – Ao Horizon made up of leaf debris, forms a mild acid humus.
The A horizon is a brown layer mergining into the B horizon, brown colour becomes lighter into the C horizon.
There are no clearly defined horizons.

7. Explaining the formation of Brown Earth Forest Soil.
Rich humus layer made up from decaying grasses and herbs and falling leaves every autumn. Compared to Podzol the humification process is quicker because of the warmer climate. Results in a mull humus this is less acidic.
Some leaching throughout the year because precipitation exceeds evaporation.

8. Continued…..
A horizon has a dark brown colour as humus replaces minerals as they are leached out. Leaching however is less pronounced here.
B horizon is less pronounced in colour because humus becomes less abundant here.
C Horizon is derived from varied parent material.
Mixing of horizons due to presence of soil biota.
Tree roots reach deep into the soil to allow any leached chemicals to be brought back up into the leaves.

9. Gleying
Is the inability of soils to shed water quickly. Often found at the foot of hills.

10. Describing Gley LOCATION – Arctic.Found it sites that are waterlogged.
CLIMATE – cold climate.
DESCRIPTION – Black Ao horizon, thin layer of black acidic humus.
A horizon is poorly drained with a dark grey colour to it.
B horizon is blue, grey with iron compounds mixed through it.

11. Explaining the formation of gley.
Weathering is slow due to cold climate.
Humification is slow because of:
Little vegetation.
Cold and dry
Few biota.
Very little leaching because:
Soil is frozen for most of year.
Subsoil is impermeable permafrost, but some leaching after snow melt.

12. continued Lack of biota because waterlogged conditions – no oxygen.
Vertical mixing in the soil takes place as a result of the annual freeze thaw cycle. This may result in poorly defined horizons.
The iron compounds in the A horizon have lost their reddish colour to a blue grey colour.
The B horizon is predominantly blue grey indicating virtually continuous water logging, this had developed on a C Horizon derived from an impermeable clay layer.

13. Key Words Illuviation Eluviation Humification Leaching
Capillary Movement
Podzolization,
Gleying