4 N. II. AGK. KXPERIMENT STATION [Bulletin 317 



CONFORMITY TO GUARANTEE 



Sixty -six of the 109 brands analyzed equalled or ex- 

 ceeded the manufacturer's guarantee. Two brands were 

 below the guarantee in each of the three constituents, 

 total nitrogen, available phosphoric acid and water sol- 

 uble potash. Seven brands were below guarantee in two 

 of the three constituents, five in nitrogen and available 

 phosphoric acid, and two in nitrogen and potash. Thirty- 

 four brands failed to meet the guarantee in only one con- 

 stituent. 



Including all the brands referred to above, 18 brands 

 were found to contain less than the guaranteed amount 

 of nitrogen. The greatest deficiency was 0.61 per cent. 

 The average of the other 17 deficiencies was 0.20 per 

 cent. Twenty-two brands failed to meet the guarantee 

 in available phosphoric acid. One brand was deficient 

 1.85 per cent. The average of the other 21 deficiencies 

 was 0.50 per cent. Twelve brands contained less potash 

 than was guaranteed. The greatest deficiency was 1.14 

 per cent. The average of the other 11 deficiencies was 

 0.39 per cent. 



Seventeen brands were guaranteed to contain mag- 

 nesium 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 italic type. The manufacturers are arranged 

 alphabetically. The brand name is listed alphabetically 

 or numerically by formula under the manufacturer. 



