12 The Bulletin 



dicalcium phosphate. The insoluble was found to also increase about 

 34 per cent. When i^arallel tests were carried on with the same acid 

 phosphate, using 20 per cent argillaceous (dirt) filler, THE SAME 

 CHAIS^GES IN THE WATER SOLUBLE AND CITRATE SOLU- 

 BLE WERE FOUND; but in this instance the COMPOUNDS 

 FORMED WERE THE PHOSPHATES OF IRON AND ALU- 

 MINUM AND NOT THE DICALCIUM PHOSPHATE. THE 

 LOSS IN INSOLUBLE WAS PRACTICALLY THREE TIMES 

 AS GREAT. 



"Ten bags of complete fertilizer, using 275 pounds of limestone, meal, 

 tankage, and sulphate of ammonia were mixed and stored. At the end 

 of seven months the bags in which these goods were stored were in as 

 perfect condition as on the day on which they were stored. One thou- 

 sand tons of complete fertilizer, using 110 pounds of ground limestone, 

 fish, sulphate, and tankage were stored in bulk; another lot of complete 

 fertilizer, using cotton-seed meal as an ammoniate, and 435 pounds of 

 ground limestone was mixed and stored. After some months the three 

 were analyzed, with the result that no apparent chemical change had 

 occurred ; in all three instances the mechanical condition of the fertilizer 

 was found to be superior to that which the writer is accustomed to 

 know where other fillers have been used. 



"In conclusion, ground limestone has a most beneficial effect on the 

 mechanical conditions and will change the water-soluble phosphoric acid 

 into the very desirable dicalcium phosphate, and the results of the sev- 

 eral experiment stations are that ground limestone will increase the 

 crop yields enormously." 



In 1914, Professor Brogdon carried out a number of experiments on 

 a number of different kinds of soil to ascertain whether the presence of 

 ground limestone in a mixed fertilizer containing acid phosphate would 

 render the phosphoric acid more or less available for plant use. Pro- 

 fessor Brogdon states : "From a number of experiments, the conclusion 

 was drawn that if phosphoric acid, nitrogen, and limestone were used 

 together as a fertilizer, larger crops could be grown than if phosphoric 

 acid, nitrogen, and potash had been used." 



"Desiring to ascertain results from this system uf fertilization as 

 applied to the cotton crop on various Georgia soils, a number of gentle- 

 men having the reputation of being practical farmers and known to be 

 interested in agricultural chemistry were asked to assist in this demon- 

 stration. Of the six men, living in six different counties widely sepa- 

 rated, each one planted three patches of cotton. Of the six men three 

 were planters who cultivate annually several thousand acres, and the 

 other three were small planters selected lor tiieir ability to carry out 

 these experiments accurately. Exactly the same size patch was culti- 

 vated in each instance, the method of cultivation being left to the experi- 

 menter. In all of the experiments the seed used were furnished by the 

 courtesy of A. C. Lewis of the office of the State Entomologist, using 



