1913.] PUBLIC DOCUMENT — No. 31. 115 



guaranteed, although ovcrmiis were used to oiTset shortages. 

 The deficiencies found were divided as follows : • — 



73 brands Avore found deficient in nitrogen. 



31 brands were found deficient in available pliosiDhoric acid. 



42 brands were found deficient in potash. 



6. That, compared with the previous year, a much better 

 showing has been made. Fewer deficiencies have occurred, also 

 a less number of commercial shortages. The number of nitro- 

 gen, available phosphoric acid and potash shortages were, re- 

 spectively, 23 less, 59 less and 24: less than for the season of 

 1911. The brands showing a commercial shortage were 2 less 

 than for the previous year. 



Table showing Commercial SJwrtages {25 Cents and Over) in Mixed Com- 

 mercial Fertilizers for 1911 and 1912. 



A number of instances have occurred, as is frequently the 

 case, where serious shortages of some one element have been 

 found and yet the brands have not suffered a commercial short- 

 age, the deficiencies being made up by overruns of some other 

 element. Although this is not a desirable feature, perhaps it 

 cannot always be avoided in the rush season. 



(3) Quality of Plant Food. — A very full discussion of the 

 quality of the plant food entering into the composition of mixed 

 fertilizers will be found in our Fertilizer Bulletin JSTo. 143. In 

 general it may be said that the quality of the organic nitrogen 

 used in fertilizers found in the Massachusetts markets showed 

 an improvement over last year. The phosphoric acid guaran- 

 tees, as a whole, were well maintained. There are indications 

 that considerable nonacidulated phosphoric-acid-containing ma- 

 terial enters into the composition of mixed fertilizers, being 

 probably derived from tankage and partly acidulated bone. 

 The potash guarantees were better maintained than during the 



