Because of the scarcity of water, agriculture had been restricted to Asir and to oases strung along the wadis, but irrigation projects relying on aquifers have reclaimed many acres of desert, particularly at Al Kharj, southeast of Riyadh, and Hofuf, in the eastern part of the country. Water also is obtained by desalinizing seawater. Agriculture is now a significant economic sector, and wheat, barley, tomatoes, melons, dates, and citrus fruit are grown, and livestock is raised. Manufacturing, which has also increased, produces chemicals, industrial gases, fertilizer, plastics, and metals. Minerals include iron ore, gold, copper, phosphate, bauxite, and uranium. There is also ship and aircraft repair. Saudi Arabia has a growing banking and financial-services sector, and the country is beginning to encourage tourism, especially along the Red Sea coast. Mecca, Medina, and the port of Jidda have derived much income from religious pilgrims; the annual hajj brings more than 2 million pilgrims to Mecca.
The oil industry, located in the northeast along the Persian Gulf, dominates the economy, comprising 90% of Saudi export earnings. Imports include machinery and equipment, foodstuffs, chemicals, motor vehicles, and textiles. Major trading partners are the United States, Japan, China, South Korea, and Germany. Oil was discovered in Saudi Arabia in 1936, and the country is now the world's leading exporter. It contains about one quarter of the world's known reserves; 14 major oil fields exist. A huge petroleum industrial complex has been developed in the town of Al Jubayl, as well as at Yanbu on the Red Sea. There are refinery complexes at Ras Tanura and Ras Hafji on the Persian Gulf; oil also is shipped to Bahrain for refining. The oil boom after World War II led to the construction of the Al Dammam–Riyadh RR, the development of Al Dammam as a deepwater port, and, especially since the 1970s, the general modernization of the country. Saudi Arabia, like other oil-rich Persian Gulf countries, depends heavily upon foreign labor for its oil industry; workers are drawn from Arab countries as well as S and SE Asia.