Saudi Arabia has no permanent rivers or lakes. Rainfall is low and unreliable. Cereals can be cultivated only through expensive projects that deplete underground reservoirs. Dairy cattle must be cooled with fans and machines that spray them with water mists. This is not, in short, a nation that would normally be associated with large-scale agriculture.

But that could be about to change. Boosted by revenues from the oil boom and concerned about food security, the kingdom is scouring the globe for fertile lands in a search that has taken Saudi officials to Sudan, Ukraine, Pakistan and Thailand.