ORGANIZATION OF THE UNITED STATES DEPARTMENT OF 
AGRICULTURE. 
Secretary of Agriculture Henry C. Wallace. 
Assistant Secretary C. W. Pugsley. 
Director of Scientific Work E. D. Ball. 
Director of Regulatory Work 
Weather Bureau Charles F. Marvin, Chief. 
Bureau of Agricultural Economics Henry C. Taylor, Chief. 
Bureau of Animal Industry John R. Mohler, Chief. 
Bureau of Plant Industry William A. Taylor, Chief. 
Forest Service W. B. Greeley, Chief. 
Bureau of Chemistry Walter G. Campbell, Acting 
Chief. 
Bureau of Soils Milton Whitney, Chief. 
Bureau of Entomology L. O. Howard, Chief. 
Bureau of Biological Survey E. W. Nelson, Chief. 
Bureau of Public Roads Thomas H. MacDonald, 
Chief. 
Fixed Nitrogen Research Laboratory F. G. Cottrell, Director. 
Division of Accounts and Disbursements A. Zappqne, Chief. 
Division of Publications John L. Cobbs, Jr.> Chief. 
Library Claribel R. Barnett, Libra- 
rian. 
States Relations Service A. C. True, Director. 
Federal Horticultural Board C. L. Marlatt, Chairman. 
Insecticide and Fungicide Board J. K. Haywood, Chairman. 
Packers and Stockyards Administration __"! Chester Morrill, Assistant 
Grain Future Trading Act Administration j to the Secretary. 
Office of the Solicitor R. W. Williams, Solicitor. 
This bulletin is a contribution from the — 
Bureau of Plant Industry William A. Taylor, Chief. 
Office of Dry-Land Agriculture Investigations- E. C. Chilcott, Agriculturist 
in Charge. 
28 
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OF THIS PUBLICATION MAT BE PROCURED FROM 
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GOVERNMENT PRINTING OFFICE 
"WASHINGTON, D. C. 
AT 
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PURCHASER AGREES NOT TO RESELL OR DISTRIBUTE THIS 
COPY FOR PROFIT.— PUB. RES. 57, APPROVED MAY 11, 1922 
