content of available plant food, particularlj^ nitrogen, phosphoric acid, and 

 potash. The presence of these constituents can only be determined by a 

 chemical analysis. To insure that they are being furnished by all manu- 

 facturers in the guaranteed amounts, it is considered necessary that each 

 brand of fertilizer offered for sale be officially inspected and analyzed one 

 or more times each year. When failure to meet the guarantee is proved 

 by chemical analysis, the prosecution or seizure provisions of the law may 

 be invoked. The purchaser's refusal to buy a fertilizer which does not 

 conform to the law in every respect will not only assist in the enforcement 

 of the law but will at the same time insure himself the protection of the 

 law. If the buyer fails to assure himself the legal requirements have been 

 met, he accepts the fertilizer at his own risk. 



All samples reported in this bulletin were drawn by an inspector ap- 

 pointed by the Commissioner of Agriculture. The chemical analyses were 

 made by the methods of the Association of Official Agricultural Chemists. 



Conformity to Guarantee 



Fifty-four of the 84 brands analyzed equaled or exceeded the manu- 

 facturer's guarantee. No brand failed to meet the guarantee in all of the 

 three constituents, total nitrogen, available phosphoric acid, and water- 

 soluble potash. Five brands were below guarantee in two of the three 

 constituents, four in nitrogen and available phosphoric acid, and one in 

 nitrogen and potash. Thirty brands failed to meet the guarantee in only 

 one constituent. 



Tncluding all the brands referred to above, 15 brHuds wej-e found lo 

 contain less than the guaranteed amount of nitrogen. The greatest defi- 

 ciency was 0.46 per cent. The average of the other 14 deficiencies was 0.17 

 per cent. Eleven brands failed to meet the guarantee in availabl phos- 

 phoric acid. One brand was deficient 8.59 per cent. The average of the 

 other 10 deficiencies was 0.64 per cent. One sample of ground bone was 

 deficient 0.25 per cent in total phosphoric acid. Eight brands contained 

 less potash than was guaranteed. The greatest deficiency was 8.61 per 

 cent. The average of the other 7 deficiencies was 0.45 ])er cent. 



Six brands were guaranteed to contain magnesium oxide. All fully met 

 the guarantee. 



In the' tabulation of the analyses in the following pages deficiencies of 

 one-fourth of one per cent or more are shown in bold-face type. The manu- 

 facturers are arranged alphabetically. The brand name is listed alpha- 

 betically or numerically by formula under the manufacturer. 



