South Sudan's decision to shut down its oil output will make many more people dependent on food aid in one of the world's most undeveloped nations, the United Nations said. (..) "The situation in the country is extremely precarious, and the risk of a dangerous decline is very real," said Valerie Amos, U.N. under-secretary for humanitarian affairs. South Sudan in 2012 will see an earlier and "longer season of hunger" than last year, she said late on Thursday after visiting Pibor town in Jonglei state which has been hit hard by tribal violence. (..) The U.N. World Food Program warns one third of its population will require food aid this year.