Soil Degradation Unit 5: Biosphere

Ms. Thind

Let’s RecapO Soil forms by:

- decaying vegetation humus

- leaching water soluble minerals move through the soil

- capillary action water pulled from deep in the soil

- translocation movement of solid material in top layers of soil

Let’s RecapO Soils of Grasslands?

- Chernozem soil

O Soils of Coniferous Forests?- Podzol soil

O Soils of the desert?- Sierozem soil

O Soils of the Tropical Rainforests?- Laterite soil

Soil Degradation What? occurs when human activity deteriorates the soil and it loses its quality and productivity.

How? Humus layer is removed composition of soil is altered loose powdery soil susceptible to wind and water erosion.

Results? Flooding, drought, dust/sand storms, infertile land for farming

O http://www.youtube.com/watch?v=sIYYOaNqDuk

Who is responsible?

Humans! Why/how you ask?

Over-cultivationO Plants are

harvested no nutrients are returned to the soil depleted humus layer soil = sand subject to erosion by wind and water.

OvergrazingO Grasslands in

arid regions where livestock graze

O Animals quickly exhaust the land leaving it bare subject to wind and water erosion

Poor irrigation practices

O Excessive watering in dry regions ↑ in salt content in soil ↓ in crops

Deforestation O Removal of

vegetation soil left unprotected left with soil where new vegetation does not grow

Desertification O Most severe form

of soil degradation O Rise in human

population ↑ demand for food

O Over cultivation, over grazing, deforestation, climate change displacement of people

How can we combat the rate of erosion?

O Build shelter belts and terraces, change farming practices