Introduction Deserts cover more than one-fifth of the Earth's land surface and can be found on all continents. A desert is defined as a location that receives fewer than 10 inches (25 cm) of rain each year. Deserts are part of a larger category of landforms known as drylands. These places have a "moisture deficit," which implies they lose more moisture through evaporation than they receive from annual precipitation. Vegetation Both hot and mid-latitude deserts are dominated b