UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 699 
Contribution from the Bureau of Soils 
MILTON WHITNEY, Chief 
_ Washington, D. C. WV hos, October 16, 1918 
ANALYSIS OF EXPERIMENTAL WORK 
WITH GROUND RAW ROCK PHOSPHATE 
AS A FERTILIZER 
By 
W. H. WAGGAMAN and C. R. WAGNER, Scientists in 
Investigation of Fertilizer Resources, assisted by R. F. 
GARDINER, Scientist in Soil Laboratory Invéstigations 
CONTENTS 
BRirGunctOn! oi.) 22s 6! ae so oo eS Results of Experiments . s e« c « o 
PVISEOLV A a ticiice Jan oeok aun ouvio fs aioe! 2 | Experience of Farmers with Raw Rock 
Theoretical considerations. . . . - » 3 Phosphate as a Fertilizer. . 2. o « o A12 
Methods of Studying the Subject . . . 5 | Semmary .. - - so © © «© © « « o 415 
ADOLACOLY: WOE cos Slo > se els s 5 | Cencllisiens) 6 ‘ei fc) 610 1a 10, 6, 6 ole 120 
Pot and Greenhouse Work .... 17 
Field Experiments . . © <« « o e 
a 
_ WASHINGTON 
GOVERNMENT PRINTING OFFICE 
