How does desertification happen?

Desertation is the accumulated results of ill-adapted land use and the effects Dersertification is the accumulated results of ill-adapted land use of a harsh climate. For human and nature represent the most immediate causes:

over cultivation

overgrazing

exhaust the soil

deforestation

poor drained irrigation

land degradtion.

Overgrazing of drylands is a big one. An immediate reason is the removal of vegetation. This is caused by a few things like drought, climate change, tillage, deforestation, and overgrazing.