Desertification

define desertification

the expansion of desert-like conditions onto land that was previously biologically productive, caused largely by unsustainable agricultural practices, especially during drought

identify where it occurs

most common in former grasslands that are now used for farming or grazing

occurs on all continents except Antarctica 

Causes of desertification

1. over cultivation of dry lands 

2. grazing

3. collection of woody shrubs for firewood

4. intense land use during drought years

5. climate change 

Mechanism of desertification via grazing

livestock eat grasses —> less plant cover —> more soil exposed 

Hooves compact soil, lowering percolation —> water runoff increases —> erosion accelerates 

Soils lose nutrients and structure —> plants fail to regrow —> land becomes barren —> desert conditions spread 

Current anti-desertification projects

1. great green wall of africa (11 african countries- plant millions of trees along the southern edge of the sahara desert)

2. great green wall of china (2800 mile forest belt built to stop the advance of the gobi desert)

Methods used to reduce desertification

1. planting trees

2. agroecology/intercropping

3. altering livestock grazing patterns