Agence France-Presse: Australia will need several years of heavy rainfall to reverse the devastating effects of a drought that has battered farm production, the Bureau of Meteorology said in a report received Monday. The report came despite months of drenching rains spawned by the La Nina weather phenomenon in the agricultural east of the country that sparked optimism that the worst drought in 100 years might at last be over. But the Bureau’s latest findings show that the “big dry,” nearly …