866 ANNUAL REPORT OF THE Off. Do«. 



3. Reverted phosphoric acid gave a greater total yield than soluble 

 phosphoric acid. 



4. Reverted phosphate of iron and alumina gave a higher yield 

 than reverted phosphate of lime. 



5. Soluble phosphoric acid gave slightly higher yields of wheat 

 (grain) than phosphoric acid in any other form. 



6. Concentrated sources of soluble phosphoric acid gave better 

 results than the low grade sources. 



7. Untreated South Carolina rock gave a higher total yield than 

 dissolved South Carolina rock. 



8. Slag phosphate produced a greater total yield and at less cost 

 than the average of the soluble phosphoric plots and the bone meal 

 plots. 



9. Insoluble phosphoric acid from slag, produced a greater yield 

 than the insoluble phosphoric acid from South Carolina rock and 

 Florida soft phosphate, but at greater cost than the two latter. 



10. For the best results with insoluble phosphates, it is desirable 

 to have the laud well filled with organic matter. Of the methods 

 tested, crimson clover w^asthe best means of obtaining this. 



EXPERIMENTS OF THE OHIO STATION. 



Tests have been conducted by the Ohio Agricultural Experiment 

 Station upon the value of different sources of phosphoric acid, at 

 three points in the State, viz: at Wooster, Strongsville and Coi am- 

 bus. The materials used in this test were raw bone meal, dissolved 

 bone black, acid phosphate and basic slag phosphate. 



The materials were applied so as to give each plot of ground the 

 same number of pounds of phosphoric acid. The plots also received 

 applications of nitrogen and potash. The quantities were the same 

 for each plot. 



The crops used in the test were corn, oats, wheat and hay, grown 

 in a five and three-year rotation. 



The results, as obtained so far, are summarized in Bulletin No. 110, 

 pages 6.5-67, of the Ohio Experiment Station. The following are 

 the summarv tables: 



