What natural zone is the Caspian lowland?

The Caspian lowland is mainly covered with steppes and semi-deserts. Due to the fact that this zone has been washed many times by the sea and the rivers that flow through it, there is little fertile soil on the surface, and it is covered with sand. Also, very little precipitation falls on these territories, only about 300 mm per year, and this also contributes to the maintenance of desert vegetation. There are many dunes and sandstorms. Fresh water is found underground, and salty water is in several lakes, the shores of which are covered with salt.