INSPECTION OF COMMERCIAL FERTILIZERS 13 



Each of 20 different firms registered five or more brands of mixed fertilizer. 

 The mixing efficiency table lists these manufacturers and shows to what 

 extent provision was made to guard against accidental deficiencies in plant 

 food due to the variation in composition of the unmixed materials or to other 

 details of the process that may not always be absolutely uniform. These 

 data were based upon tonnage as well as composition of the different brands 

 of each manufacturer. It is gratifying to note that all of the twenty firms 

 listed showed an overrun in all three plant food elements. It will be noted, 

 however, that two firms showed an overrun of less than one-tenth of 1 per 

 cent in nitrogen, and four other firms showed an overrun of less than one- 

 tenth of 1 per cent in potash, an amount which is usually considered too 

 small to safely care for accidental variations in the composition of the crude 

 stock materials which go into the mixtures. In available phosphoric acid the 

 overruns were more liberal and were sufficiently high to be safe in all instances. 



Adoption of Simplified Guarantees on Mixed Fertilizers. 



The past year has marked the adoption of a new and simplified method of 

 expressing the plant food guarantees on mixed fertilizers. In all mixed 

 fertilizers the grade has been made a part of the brand or trade name, and 

 has been expressed in terms and order of nitrogen, available phosphoric acid, 

 and water soluble potash. This has been accompanied in all cases by a 

 formal statement of the minimum guarantee only of these three plant food 

 elements. Exceptions to this rule are but few, and are confined to bone-base 

 mixtures where all of the phosphoric acid is derived from unacidulated bone. 

 In these cases, the total as well as the available or citrate soluble phosphoric 

 acid has been stated. Chemicals, unmixed fertilizer materials, and pulverized 

 animal manures have not been included in this change, and may be guaranteed 

 in fractional percentages as in the past. 



It should be very encouraging to the individual manufacturers, as it is to 

 the control officials, that there exists the splendid spirit of cooperation neces- 

 sary to institute so readily the improvement in grades only recently recom- 

 mended. That the user will welcome the change can be reasonably anticipated. 



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 valuation 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 1932, 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 guaran- 

 tee 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 

 overruns which largely offset the value of the deficiencies. 



