Biosphere

Question 1

Podzol soil (8)

Answer 1

1. Found at the top of slopes in cold and wet conditions.
2. Shallow roots means little recycling of nutrients leading to infertile soil.
3. Horizon A is an ash grey layer due to leaching.
4. In Horizon B an iron pan forms because precipitation exceeds evaporation leading to leaching. This can also impede drainage. Precipitation or snow melting can cause this.
5. Parent material is acidic rocks such as granite or shists. These are impermeable rocks which can impede drainage.
6. Coniferous trees found here due to alpine conditions.
7. Needles fall and decompose slowly due to cold conditions creating the black acidic mor layer.
8. No organisms because it is too cold to survive. This leads to no mixing of the soil giving clearly defined layers.

Question 2

Brown earth soil (8)

Answer 2

1. Found in the middle of a slope.
2. Deep roots allow nutrients to be recycled making it fertile.
3. Precipitation exceeds evaporation in winter leading to leaching but precipitation exceeds evaporation in summer known as capillary action.
4. Deciduous trees found due to warmer conditions.
5. Leaf litter falls and decomposes quickly to form mull.
6. Organisms survive due to warmer conditions.
7. They mix the souls so there is no defined layers.
8. Parent material is sandstone/limestone which allows for better drainage.

Question 3

Gley soil (8)

Answer 3

1. Found at the bottom of slopes in very wet and cold conditions.
2. Precipitation exceeds evaporation creating a blue horizon A.
3. Permafrost horizon B which leads to poor drainage.
4. Soil remains frozen for most of the year. When in summer it thaws and created waterlogged conditions.
5. Mainly mosses and lichens due to cold temperatures.
6. Due to cold conditions we only get partial decomposition which creates a thick, black humus layer.
7. No organisms due to cold conditions and anaerobic conditions give clear layer.
8. Parent material is coastal sand and glacier till (horizon C)