The Mediterranean soil is also responsible for the poverty it inflicts on its peoples, with its infertile limestone, the great stretches blighted with salt, the lands covered with nitre, its rare deposits of loose soil, and the precariousness of its arable land. The thin layers of topsoil, which only the modest wooden swing-plough can scratch, are at the mercy of the wind or the flood waters. They are enabled to survive only by man’s constant effort.

Fernand Braudel
historian
‘The Mediterranean and the Mediterranean World in the Age of Philip II, Volume One’