Professor Bouldin's research interests are soil fertility, soil chemistry and the root-soil interface in both upland and flooded soils. Major areas of current research interests are A) Management of soil acidity with emphasis on how to ameliorate subsoil acidity and how to match cultivars to existing subsoil acidity condition, B) multi-ion models of crop mineral nutrition and C) chemistry of the root-soil interface in upland and flooded soils.