No. 7. 



DEPARTMENT OF AGRICULTURE. 



TABLE B. 



145 



o 

 p. 





3 



■a . 

 ■o 



CO a! 

 O 



Soluble phosphoric acid 



Reverted phosphoric acid 



Insoluble phosphoric acid, ground bone, 

 Insoluble phosphoric acid, S. C. rock, ., 



No phosphoric acid, 



Nothing 



5.74 

 24.29 

 33.95 

 29.42 



Taking the average for the 12 years, insoluble phosphoric acid from 

 ground bone gave a gain of 79 cents per year, and insoluble phospho- 

 ric acid from South Carolina rock a gain of 41 cents. Soluble phos- 

 phoric acid showed a loss of |1.56 per year, reverted phosphoric acid 

 a loss of 43 cents, and the nitrogen and potash plots a loss of |2.04 

 per year. 



A study of the results of these different experiments, all pointing 

 in the same general direction, would seem to indicate a necessity for 

 revising our teaching somewhat with reference to the use of insoluble 

 phosphoric acid. It would not be proper to advise their use generally 

 in an untreated form, but it is a matter upon which it might pay the 

 individual to experiment. It should be borne in mind, in this mat- 

 ter of the most economical method of fertilization, that one must be 

 guided by the object sought or the particular kind of farming in 

 which he is engaged so that a system suitable for one may not be 

 for another. 



The CHAIRMAN: The Round Table will be taken up immediately. 



The DEPUTY SECRETARY: These questions we expect to have 

 published. Where you give oral questions, give them as concisely 

 as circumstances will permit. Keep in mind that it is our intention 

 to publish these questions and answers. 



A Member: Mr. Chairman, I would ask if the questions must nec- 

 essarily be pertinent to the subject discussed. 



The DEPUTY SECRETARY: Certainly; only questions pertinent 

 to the subject under discussion. 



ROUND TABLE. 



(Conducted by Prof. McDoweU.) 



A Member: Is there any difference in phosphoric acid from bas- 

 ket-slaked bone or rock? 

 10—7—1904 



