Report on Magnesium and Manganese

Fertilizers

“…The two official methods for manganese in fertilizers (14, p. 36) -the colorimetric permanganate and the volumetric bismuthate procedures-were adopted after extensive collaborative studies by Smith and Deszyck (263). In the persulfate method as modified by Hillson (114), addition of disodium phosphate to the solution facilitates reduction of excess persulfate, and use of osmium tetroxide as a catalyst aids in the arsenite titration of the permanganate.…”