Desertification is when land turns into desert. This means that little or no food can be grown in areas where people live and farm the land. Desertification is caused by the following factors

1. Deforestation - This directly leads to lower rainfall and higher temperatures
2. Overcultivation - growing too many crops, year after year on the same piece of land damages the soil structure and reduces the soil fertility
3. Overgrazing - the cattle, sheep, goats and other animals take away the vegetation cover and expose the bare soil
4. Poor irrigation - this can make the ground too salty (salinisation)
5. Drought - extended periods of lower than usual rainfall damages the vegetation
6. War - this causes refugees to move into marginal land

Most of all desertification is caused by the pressure of too many people living in an area.