EXPEEIMENTAL WOEK WITH RAW ROCK PHOSPHATE. 



15 



Forbes and Fritz ^ suggested the introduction of floats into the 

 silo in order that the fermentation process and the subsequent pass- 

 ing of the ensilage through the animal's body would aid in rendering 

 the rock phosphate more soluble. The following table gives a 

 summary of the analytical results obtained by these investigators. 



Table VI. — Phosphorus in silage corn with and without added floats, and in 



silage made therefrom. 





Average content of phosphorus on water-tree basis. 



Material. 



Total. 



Water 

 soluble. 



Citrate 

 soluble. 



Soluble 

 in 0.2 per 

 cent HCl. 



Water 



soluble plus 



citrate 



soluble. 





Per cent. 



0.207 



.224 



.371 



.384 



Per cent. 



0.149 



.160 



.136 



.157 



Per cent. 



0.021 



.008 



.061 



.060 



Per cent. 



0.083 



.111 



.172 



.237 



Per cent. 

 0.170 





.168 





.197 





.217 







If the total quantity of phosphoric acid in the material is consid- 

 ered, it will be seen that the fermentation process actually decreased 

 the percentage of water-soluble plus citrate-soluble phosphoric acid 

 present in the silage corn. Fermentation also produced little or no 

 effect on the citrate solubility of floats mixed and charged to the silo 

 with the corn. The amount of phosphate dissolved by a 0.2 per cent 

 solution of hydrochloric acid, however, was considerably increased by 

 the ensilage process. If this were an index of availability (an as- 

 sumption which is hardly warranted) the mixing of phosphate rock 

 with ensilage might be considered good practice. 



Mooers,^ however, carried this investigation somewhat further and 

 actually determined the citric-soluble phosphate in the dung of ani- 

 mals fed with ensilage treated with floats, comparing the results with 

 the dung of similar animals fed with untreated ensilage. 



The treated ensilage was produced by charging the silo with finely 

 ground rock phosphate and corn at the rate of 2 pounds of ttie former 

 to 100 pounds of the corn. It was assumed that the increased amount 

 of total phosphoric acid in the dung of the animals fed with the 

 treated ensilage was due to the rock phosphate in the ensilage. In 

 order to have a check on the effect of fermentation and the subse- 

 quent digestive process on the solubility of the phosphate, an 

 amount of rock phosphate equal to that in the dung produced from 

 the treated ensilage was added to the dung produced from un- 

 treated ensilage. The results of this investigation are summarized 

 in Table VII. 



iJour. Ind and Eng. Chem., 6, 222 (1914). 

 « Jour. Ind. and Eng. Chem., 6, 487-8 (1914). 



