Ecosystems

Farming in the oases

In desert areas farming develops in oases. In the beginning there may be one palm only, planted in a dug-out area and surrounded by dead branches to protect it from the sand. Large crops develop over time, but the water needed for the vegetation to grow does not flow out freely. A tiring and rigorous work must be carried out by man to take water from underground. With time, man has built underwater tanks to collect water and long channels to carry it. They need constant maintenance to remove the sand or stones that could settle there and obstruct them. Every oasis has its typical irrigation system: for instance in Ghardaya (in the Mozab valley), in the Sahara, water flows underneath the dry bed of an old river. Over one million date palms are irrigated by a sophisticated system that controls the underground flow. It is a widespread system made up of dams, weirs and wells, that channel, select and dispense water, so that all gardens receive the right amount of it. In other oases, such as those of the Souf region, where the water table is very close to the surface, the farmers have found out another clever method to water the palm groves: instead of irrigating the surface with wells and channels, they dig out real craters for the palms, so the palms can reach the water with their roots: a clever trick that avoids waste due to evaporation and offers the plantations effective protection against the wind and sand.