33 



but high grade materials should go into the mixtures. Infor- 

 mation has reached him from other sources that the company 

 have been known to use considerable quantities of garbage tank- 

 age. 



Ross Brothers Co. This same brand showed an unsatisfactory 

 activity of its organic nitrogen last year. The company stated 

 that the organic nitrogen was derived from sheep manure, tobacco 

 dust and bone, and it is quite probable that the sheep manure 

 and tobacco dust are responsible for the trouble. It might be 

 added that the total nitrogen guarantee was more than made up 

 by the mineral forms of nitrogen present. 



Summary. 



1. The quality of the organic nitrogen used in the fertilizers 

 sold in Massachusetts for 1912 shows an improvement over last 

 year. There is, however, chance for further improvement. 



2. A number of brands showed an activity of water insol- 

 uble organic nitrogen slightly under 50%, but the presence of a 

 relatively large amount of water soluble nitrogen allowed us to 

 pass them without special mention. The standing of each one, 

 however, is given in the tables of analysis; brands having an 

 inactive water insoluble organic nitrogen greater than the active 

 water insoluble should be viewed with suspicion. 



3. From what has been said it will not be a hard task for 

 anyone to pick out those brands where nitrogen-containing ma- 

 terial of low availability has been used in furnishing a part of the 

 nitrogen guarantee. These are the serious cases and it is hoped 

 that conditions will improve another season. 



Although the phosphoric acid guarantees are 

 Character of better maintained than last year, yet there 



Phosphoric seems but little difference in the relative pro- 



Acid, portions of soluble, reverted and insoluble 



forms in the fertilizer mixtures. Of the total 

 phosphoric acid found in all of the brands analyzed, 83 percent 

 was present in available form, and of the available 57 percent was 

 in water soluble form. 



There are indications that a considerable quantity of nonacid- 

 ulated phosphoric-acid-containing materials enters into the com- 

 position of mixed fertilizers. As proof of this, it may be men- 

 tioned that 15 samples of acid phosphate were analyzed during 

 the year and 96 percent of the average total phosphoric acid was 

 classed as available. Of the available phosphoric acid, 78 per- 

 cent was in water soluble form. These are considerably larger 

 percentage solubilities than are found in the complete fertilizers. 

 Undoubtedly considerable of the less soluble and available phos- 



