12 CONTROL SERIES No. 69 



Nineteen different firms registered five or more brands of mixed fertilizer. 

 Based upon composition found as well as upon tonnage sold, the above table 

 shows to what extent each manufacturer was successful in guarding against 

 deficiencies in plant food guarantee in his assembled mixtures. All of the 19 

 firms provided for a fair margin of overruns in nitrogen; three firms failed to 

 supply enough available phosphoric acid, and four firms failed to supply sufficient 

 potash to meet the average guarantees. In four other cases the overruns were 

 too small to safely care for accider^tal variations in the composition of the unmixed 

 materials used in assembling the mixtures. 



Explanation of Tables of Analyses. 



Guarantee. This column gives the manufacturer's claim or guarantee for 

 the three elements of plant food, nitrogen, available phosphoric acid and potash, 

 in the order stated. The grade of each fertilizer is made a part of the trade name 

 and is expressed as nitrogen, available phosphoric acid and water soluble potash, 

 and in that order. 



Commercial Shortages. In the table designated "Mixtures showing a 

 commercial shortage of $1 or more per ton," the column headed "Approximate 

 commercial v^aluation per ton" gives the sum of the valuation of each plant 

 food element computed from the analysis by use of the trade values adopted 

 by the Massachusetts Fertilizer Control for 1933, which appear on a preceding 

 page of the bulletin. 



Under the heading "Approximate commercial shortage per ton" is shown the 

 commercial valuation of the deficiencies or tests found below the guarantee 

 after allowance is made for the value of overruns or tests above the guarantee. 



Deficiencies are emphasized by boldface type. 



Mixtures Substantially Complying with the Guarantee. In addition 

 to the analysis of those fertilizers substantially complying with the guarantee, 

 this table includes also those mixtures that are more or less out of balance; 

 that is, having deficiencies in one or more plant food elements, but having over- 

 runs which largely offset the value of the deficiencies. 



"Number of samples" indicates the number of samples included in the com- 

 posite which was analyzed. 



Inferior Nitrogen. The presence of inferior forms of organic nitrogen is indi- 

 cated by footnotes. 



Potash Forms. Wherever tests for chlorine showed a sufficient amount present 

 to unite with all of the potash found, the source of the potash is designated as 

 muriate. Wherever insufficient chlorine was found to account for all of the 

 potash it is evident that forms of potash other than muriate were used. In 

 such cases, the figures under the sub-heading "As muriate" do not imply nec- 

 essarily that muriate of potash was actually added to the mixture, but that 

 chlorine was present, probably from impurities in the fertilizer chemicals, in 

 amounts to account for the percentage of potash indicated. The balance of the 

 potash found is listed under the sub-heading "In forms other than muriate" 

 and may be derived from sulfate, nitrate, or carbonate, as the case may be. 



