INSPECTION OF COMMERCIAL FERTILIZERS 15 



tions was found to be of average quality, being well above the passing mark of 

 50 per cent by the alkaline and 80 per cent by the neutral methods. The only 

 brand found that could not be "passed" was Harvest Brand 2-8-2, manufactured 

 by the Piedmont-Mt. Airy Guano Co. This brand had .58 per cent of water 

 insoluble nitrogen which showed an activity of 46.2 per cent by the alkaUne 

 and 58.8 per cent by the neutral permanganate method. A number of other 

 brands by different manufacturers showed low activities of the insoluble nitro- 

 gen, but were "passed" for the reason that the minimum nitrogen guarantee 

 was fully met by the more active nitrogen forms. 



Explanation of Tables of Analyses. 



The column headed "Grade of Fertilizer" gives the minimum guarantee of 

 ammonia, available phosphoric acid and potash, always stated in this order. 

 To convert ammonia to equivalent nitrogen, multiply by the factor .82. 



In the table headed "Mixtures Showing a Commercial Shortage of $1 or More 

 Per Ton," under the heading "Approximate Commercial Valuation Per Ton," 

 is found the sum of the valuation of each plant food element calculated on the 

 basis of analysis and trade values adopted for 1928, which appear on a preceding 

 page of the bulletin. 



In the same table, under "Approximate Commercial Shortage Per Ton," is 

 shown the commercial valuation of the deficiencies or tests found below the 

 guarantee, per ton of fertiHzer, the value of overruns being used in all cases to 

 offset valuation of shortages. 



Under "Mixtures Showing a Commercial Shortage of $1 or More Per Ton," 

 and "Mixtures Seriously Out of Balance But Not Having Commercial Shortage," 

 deficiencies are emphasized by boldface type. 



In those tables headed "Mixtures Substantially Complying with Guarantees" 

 under "Nitrogen" the column headed "Proportion in Mineral Form" includes 

 both the ammoniacal and nitric nitrogen, both of which are water soluble and 

 readily available. Footnotes indicate any considerable proportion of the min- 

 eral nitrogen derived from nitrates; the absence of footnotes indicates that the 

 greater part is derived from ammoniacal sources. Under "Quality of Insoluble 

 Nitrogen" in all of the tables of mixed fertilizers, passed indicates an activity 

 of 50 or over by the alkaline and 80 or over by the neutral permanganate method; 

 inferior indicates an activity below 50 and below 80 by the respective labo- 

 ratory methods. All samples are passed ^which show an activity of the water 

 insoluble nitrogen of 80 per cent or better by the neutral method, even though 

 they may have shown a test below 50 per cent by the alkaline method. All 

 samples are passed which show the sum of the mineral, water soluble organic, 

 and active water insoluble organic nitrogen equivalent to the min imum guarantee. 



In those tables headed "Mixtures Substantially Complying with Guarantees" 

 in the column marked "Form of Potash," the word muriate means that enough 

 chlorine was found present to unite with all of the potash (K2O) found, and it 

 is likely, therefore, that all of the potash was derived from chloride of potash 

 or muriate. 



Figures in parenthesis following the brand name, in these tables, indicate the 

 number of samples from which the composite sample finally analyzed was drawn. 



The detailed results of analysis of any brand inspected will be gladly 

 furnished to anyone sufficiently interested to apply for them. 



