46 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



In normal soils I have said there are only three things to 

 consider, and I don't want you to pick up these agricultural 

 papers and say, ''Here is sulphur. Hopkins did not seem to 

 know anything about it," I have in my hand fifteen years of 

 field experiments, and another fifteen years, both under direc- 

 tion of Dr. Charles E. Thorne, who has been director for 

 twenty-five years of the Ohio Experiment Station, and during 

 these twenty-five years has furnished to the United States the 

 most valuable information that we have today. He had a five 

 year rotation of crops of corn, oats, wheat, clover and timothy. 

 He had five different fields, that each crop might grow every 

 year in the rotation. He thus had five crops each year for fif- 

 teen years, which made seventy-five tests. This was at Wooster. 

 He also had seventy-five similar tests at Strongsville, Ohio. 



He applied bone meal as a source of phosphorus, and it cost 

 him at the prices that prevailed at the Ohio Station $2.60 to 

 apply this bone meal per acre of land, and the returns from it 

 were $19.61. He put it on two or three times during the five 

 year period, but the cost for all applications was $2.60, each 

 five years, and the total returns he reports as $19.61 on this in- 

 vestment of $2.60. 



He applied phosphorus in another form, slag phosphate, a 

 by-product of the manufacture of steel from pig iron, made 

 from iron ore rich in phosphorus. Where this basic slag was 

 used he applied the same amount of phosphorus, at a cost of 

 $2.60, and the return was $19.99. That shows, of course, a 

 very high profit from the use of phosphorus on ordinary soil 

 which needs phosphorus for ordinary farm crops. 



Another test made m connection with these was that, in- 

 stead of using bone meal or slag phosphate, they used acid 

 phosphate, made by treating some insoluble phosphorus, such 

 as bone ash or bone black, with sulphuric acid. It carries as 

 much sulphur as phosphorus, so that if sulphur is as needful as 

 phosphorus, and if the bone meal and the slag gave us $19 in- 

 crease, then with the same amount of phosphorus applied in the 

 form of acid phosphate, also as much sulphur as phosphorus, 

 we would expect about the same increase, for phosphorus, and 



