The origin of citrus fruits can be located in Southern Asia: the bitter orange seems to come from southern China, the sweet orange from Indochina and China, the citrus and lemon from India and the mandarin from the Samoa Islands.
But the merit to have diffused lemons and bitter oranges in the Mediterranean from the Tropics of the Far East belongs to the Arabs (instead the
citrus was well known by the ancient Roman as we can see from the mosaics in Pompei) together with rice, sugar cane, wheat, cotton and a varieties of other plants.
We are also told that the beginning of th 19th century citrus trees were considered to be ornamental trees, from this the nomenclature, still in use today "citrus fruit garden".
These cultivation's predilect hot climates, therefore it was understood immediately that this fruit would give the farmers of that time the possibility to work also in summer, a dead season in the ancient agricultural calendar, but for their acclimatisation they soon found out that specific and attentive care was necessary, in particular they had a great need of water, that with difficulty could be supplied by nature in Sourthern Europe and North Africa.
Here infact because of the luminosity and the dryness of th earth, the water resorces in the summer months resulted a lot higher than in the umid climates of the regions of origin.
Only artificial irrigation could overcome the difference.
The coming of the Arabs radically changed the production techniques introducing structural modifications, and above all good irrigation, that were adapted for use and inserted into a coherent system.
So very rightly this is called an "Arabian agricultural revolution". Even if some more innovations were destined to emerge succesively.
For example at the end of the XV century with the diffusion of the sweet orange, the one later to be called "Portugal", or in the middle of the Sixth century with the cross breed between lime and lemon that gave life to Bergamotto. The continuation of the Muslim tradition appears evident, above of all in Sicily from where certain techniques expand.
The same word "Zagara" is of Arabian origin
"Zahara", and all the terminology still used today on the island to indicate machines and irrigation works echo with Arabian roots.
"Giarre": are the so called towers through which the water was sorted.
"Gebbie": the tubs in which the water is collected.
"Saie": the channels dug in the earth or made of stone along wich the water was distributed.
"Zappa": was the hourly unit of mesaurement of the water.

"Senie" o "Zenie": were the machines that by means of wheels and bowls lifted the precious liquid from the wells, from the rivers, from the tubs, both words in Arabic mean "An Irrigated Garden".