6 



becomes available to plants the first season. This is facili- 

 tated by combining them with cotton seed meal. Floats and 

 cotton seed meal have uniformly equaled acid phosphate and 

 cotton seed in producing power." 



EXPERIMENTS IN THE FIELD TO TEST THE ABOVE MENTIONED 



RESULTS. 



To test more thoroughly the comparative productiveness 

 of ground raw phosphate and acid phosphate under different 

 conditions and to determine whether decomposing organic 

 matter converts insoluble into soluble phosphate, two sets of 

 experiments were carried out, one on the farm and the other 

 in the chemical laboratory, the results of which will now be 

 given. 



The materials used were carefully analyzed by Dr. Ander- 

 son, assistant chemist, with the following results: 



The acid phosphate used gave 

 Water Soluble Phosphoric Acid (Po O5 ) . .9.10 per cent. 



Citrate " " " 2.94 



Acid " " " 2.32 



Total phosphoric acid (P2 O5 ) .... 14.36 



(( 



The Florida phosphate reduced to a fine powder similar 

 to floats, gave 



Moisture 4.18 



Insoluble matter 32.39 



Total phosphoric acid (acid soluble) 16.54 



Iron and aluminium oxides 8.89 



None of the lime phosphates were soluble in water and 

 only 0.32 was soluble in ammonium citrate. The analysis 

 shows an inferior grade of raw phosphate. The material 

 purchased as "South Carolina floats" contained 2.26 per 

 cent, of available phosphoric acid in the form of citrate — sol- 

 uble acid and a total phosphoric acid of 28.73 per cent. Th®" 



