CALGARY — Agrium Inc. (TSX:AGU) is preparing to expand its agriculture retail business in the United States with the acquisition of 20 farm-supply locations in Georgia and Florida.The Calgary-based company, which also has a wholesale fertilizer business, says its U.S. retail distribution network will be enhanced through a binding purchase agreement with Southern States Cooperative.It will also acquire an integrated cotton ginning business in Statesboro, Ga.Agrium didn’t announce financial terms of its purchase, which is expected to close in September, but estimates the acquired locations will generate more than $100 million in annual revenue.Southern States Cooperative, based in Richmond, Va., is a farm supply retailer that sells fertilizer, seed, livestock feed, animal health supplies and other products for the farm and home through 1,200 retail outlets in 23 states.Agrium also has an agricultural retail network in the U.S. and Canada while its wholesale operations produce nitrogen, potash and phosphate fertilizers for the global market.It is in the process of combining with Saskatoon-based PotashCorp (TSX:POT) in a previously announced deal.