INSPECTION OF COMMERCIAL FERTILIZERS 



45 



Stone MeaL 



a Menderth contained .055% and McCrillis Stone Meal .06% of potash soluble in water. 



Note: The commercial value of the plant food contained in one ton of these 

 Stone Meals, based upon their content of acid soluble potash, phosphoric acid, 

 calcium and magnesium, would be about $1.81 for Menderth and $L11 for the 

 McCrillis Stone Meal. 



Definitions and Interpretations Relating to Fertilizers. 



The following definitions and interpretations have been adopted as official 

 by vote of the Association of Official Agricultural Chemists at meetings held in 

 1932, 1933 and 1934. 



The term lime shall not be used in the registration, labeling, or guaranteeing 

 of fertilizers or fertilizer materials unless the lime is in a form to neutralize soil 

 acidity (the oxide, hydroxide or carbonate, or equivalent magnesia compounds). 



The weights appearing on packages of fertilizer, agricultural lime, and liming 

 material shall always mean net weights. 



Citrate-soluble ("reverted") phosphoric acid is that part of the total 

 phosphoric acid in a fertilizer that is insoluble in water but soluble in a solution 

 of citrate of ammonia according to the method adopted by the A. O. A. C. 



Agricultural liming material is any substance that contains calcium and 

 magnesium in condition and quantity suitable for use in neutralizing soil acidity. 



Phosphate rock is a natural rock containing one or more calcium phosphate 

 minerals of sufficient purity and quantity as to permit its use, either directly or 

 after concentration, in the manufacture of commercial products. 



Soft phosphate with colloidal clay is a very finely divided low-analysis 

 by-product from mining Florida rock phosphate by a hydraulic process in which 

 the colloidal material settles at points in artificial ponds and basins farthest 

 from the washer, and is later removed after the natural evaporation of the water. 



Precipitated bone phosphate is a by-product from the manufacture of 

 glue from bones and is obtained by neutralizing the hydrochloric acid solution 

 of processed bone with calcium hydroxide. The phosphoric acid is chiefly 

 present as dicalcium phosphate. 



Precipitated phosphate is a product consisting mainly of dicalcium phos- 

 phate obtained by neutralizing with calcium hydroxide the acid solution of 

 either phosphate rock or processed bone. 



"Basic" lime phosphate (lime based superphosphate) is a superphosphate 

 to which liming materials have been added in a quantity at least six per cent (6%) 

 calcium carbonate equivalents in excess of the quantity required to convert all 

 water-soluble phosphate to the citrate-soluble form. 



