24 



Phosphoric Acid in Mixed Fertilizers. Of the total phosphoric 

 acid found in the complete fertilizers, 83.5 per cent was in available 

 form, and 49.2 per cent of the available phosphoric acid was in water 

 soluble form. In the ammoniated superphosphates 83.00 per cent 

 of the total phosphoric acid was in available form and 54.00 per cent 

 of the available phosphoric acid was in water soluble form. These 

 figures are about the same as in previous years and show a satisfac- 

 tory availability. 



Potash in Complete Fertilizers. The average complete fertilizer 

 contained 1.78 per cent of water soluble potash. The larger propor- 

 tion of the brands had but 1.00 per cent of potash, several had 2.00 

 per cent and four had a minimum of 4.00 per cent guaranteed. Out 

 of a total of 137 samples analyzed, 47, or 34.00 per cent, failed to 

 meet the minimum potash guarantee. In most instances, however, 

 the deficiencies were not serious. 



Seventeen brands of tobacco fertilizer have been examined. 

 Seven of these, or 41.00 per cent of the total number, had their potash 

 in form of sulfate, only traces of chlorine being present. Two brands 

 had all of their potash as muriate and eight brands showed an average 

 of .54 per cent of potash as sulfate and .46 per cent as muriate. 



The same form of publication has been retained in the tables as 

 in previous years. An asterisk has been used in the potash "Found" 

 column in all cases where a considerable proportion of the potash has 

 been found as sulfate. Footnotes designate the proportion of each 

 form of potash. 



LIME COMPOUNDS. Forty-five samples of hme products 

 have been examined, necessitating 34 analyses, representing 28 dis- 

 tinct brands. The tables of analyses will be found self-explanatory, 

 the analytical data being presented in the same form as in previous 

 years. The guarantees of calcium and magnesium oxides have, as a 

 general rule, been well maintained in all the groups. A study of the 

 tables of analyses emphasizes the fact that the purchaser of lime 

 products for agricultural purposes should pay particular attention 

 to the chemical and mechanical condition of the various offerings, as 

 well as the cost of 100 pounds of actual calcium and magnesium 

 oxides. In case of the raw ground hmestones, the finer they are 

 ground the more effective do they become in their effect upon the 

 soil. This may not be true to the same extent in case of burned 

 granulated lime, or the hydrated or slaked products, as they are more 

 active chemically than the unburned or raw ground limes. In general 

 it may be said that the fine ground limestones may be found better 

 adapted to the lighter soils, while the more active lime products 

 usually have a better physical effect on the heavier soils. 



