2014-07-212014-07-211947https://hdl.handle.net/10365/23239At this writing in 1947, there was an apparent shortage of superphoshate and other types of phosphate fertilizers with readily available sources of phosphoric acid. This article attempts to answer the question regarding the effectiveness of rock phosphate and colloidal phosphate for fertilization of crops culled from tests with Tennessee rock phosphate in North Dakota. Tests revealed that this was not a good substitute for those containing much higher concentrations of phosphoric acid.North Dakota State UniversityArticle