Agriculture is constrained by lack of adequate fertile soil, rainfall, and underground water sources; the aquifers which supply the crops are expected to soon run dry. Recently, treated waste water has been used for irrigation. In 1998, only 1.5% (17,000 hectares/42,000 acres) of the total land area was under cultivation. In 1999, 23,000 tons of dates were produced, mostly for local consumption. Rice is also grown for the domestic market.