Pot culture experiments for the investigation of methods of application of powdered rock phosphate were conducted on a red earth and a slightly calcareous alluvial soil. The former is extremely deficiency in phosphatic nutrients, having a pH of 4.8, while the latter is a very fertile soil of about neutral reaction. Both soils received pretty supply of nitrogeneous and potassic fertilizers with following variations of phosphorus treatment. Rice was used as an indicating crop.