The article describes the history of the foundation of the All-Russian Sugar mills Company, its activities throughout the entire period of its existence, and also the role in the further development of the sugar industry of the Empire. The work of Oscar Karlovich Kedrov-Zikhman in the laboratory of The Experimental fields Network of the All-Russian sugar mills society on the evaluation of methods for determining citrate-soluble phosphoric acid in Thomas slag is presented. The use of mineral fertilizers that is rapidly expanding in Russia has put forward to the Russian control stations the question of choosing the most accurate and most suitable for mass studies analysis methods. Until now, Russian laboratories have adopted methods approved by the Union of Agricultural Experimental Stations in Germany, which were usually taken on faith without prior critical analysis. The Laboratory of the Experimental Fields Network of the All-Russian Sugar Mills Association, first of all, focused its attention on the research methods of thomas slag due to their great diversity. In his work, Oskar Karlovich compared the following methods to each other: The molybdenum method, with and without the preliminary removal of silicic acid; Lorenz’s method; Rohrr’s method; Hydrochloric acid method; Darmstadt method; Naumann’s method. According to the results of the research, the scientist identified the pros and cons of each of them.This work was of great practical importance, since as a result, the most accurate and suitable method for conducting mass research was determined

The All-Russian sugar mills society; The experimental fields Network; Mironovskaya Central experimental station; O.K. Kedrov-Zikhman; Thomas slag; research methods