ORGANIZATION OF THE UNITED STATES DEPARTMENT OF AGRICULTURE 

 WHEN THIS PUBLICATION WAS LAST PRINTED 



Secretary of Agriculture Hexry A. Wallace. 



Under Secretary M. L. Wilson. 



Assistant Secretary Harry L. Browx. 



Director of Extension Work C. W. Warburtox. 



Director of Finance W. A. Jump. 



Director of Information M. S. Eisenhower. 



Director of Personnel W. W. Stockberger. 



Director of Research James T. Jardixe. 



Solicitor Mastix G. White. 



Agricultural Ajdustment Administration H. R. Tollet, Administrator. 



Bureau of Agricultural Econo?nics A. G. Black, Chief. 



Bureau of Agricultural Engineering S. H. McCrory, Chief. 



Bureau of Animal Industry Johx R. Mohler, Chief. 



Bureau of Biological Survey Ira N. Gabrielsox, Chief. 



Bureau of Chemistry and Soils : Hexry G. Kxight, Chief. 



Commodity Exchange Administration J. W. T. Dttyel, Chief. 



Bureau of Dairy Industry O. E. Reed, Chief. 



Bureau of Entomology and Plant Quarantine- Lee A. Stroxg, Chief. 



Office of Experiment Stations James T. Jardixe, Chief. 



Food and Drug Administration Walter G. Campbell, Chief. 



Forest Service Ferdixaxd A. Silcox, Chief. 



Bureau of Home Economics Louise Staxley, Chief. 



Library Claribel R. Barxett, Librarian. 



Bureau of Plant Industry Frederick D. Richey, Chief. 



Bureau of Public Roads Thomas H. MacDoxald, Chief. 



Resettlement Administration W. W. Alexander, Administrator. 



Soil Conservation Service H. H. Bexxett, Chief. 



Weather Bureau Willis R. Gregg, Chief. 



This circular is a joint contribution from 



Bureau of Chemistry and Soils Hexry G. Kxight, Chief. 



Fertilizer Research Division C. H. Kuxsmax, Principal Physi- 

 cist, in Charge. 



Bureau of Plant Industry Frederick D. Richey, Chief. 



Division of Soil Fertility Investigations.. 0. Schreixer, Principal Biochem- 

 ist, in Charge. 

 12 



U. S. GOVERNMENT ?R:s~ N3 OFFICE: 1937 



For sale by the Superintendent of Documents, Washington. D. C. Price 5 cents 



