1913.] PUBLIC DOCUMENT — No. 31. 115 



giiarantcccl, although ovcrnius were used to oiTsct sliortagca. 

 The deficiencies found were divided as follows: — 



73 hiaiids wero found doHcicnt in nitrogen. 



31 l)rands were found delicient in available ])hosi)lione acid. 



42 brands were found delicient in jiotasli. 



G. That, compared with the jn-evious 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 

 1011. The brands showing a commercial shortage were 2 less 

 than for the previous year. 



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

 mercial Fertilizers for 1911 and 1912. 



A nmnber of instances have occurred, as is frequently the 

 case, where serions 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 Xo. 1-13. In 

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

 nsed 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 



