No. 6. DEPARTMENT OF AGRICULTURE. ?!» 



FERTILIZER ANALYSES, JANUARY 1, TO AUGUST 1, 1901. 



During the six months ending July 1, 1901, there were received 

 from the authorized sampling agents, eight hundred and seventeen 

 (817) fertilizer samples, of which four hundred and fifty (450) were 

 subjected to analysis, the remainder being rejected either because 

 they represented brands analyzed last season, or because they were 

 regarded as not certainly representative of the brand whose name 

 they bore. When two or more samples representing the same brand 

 were received, equal portions from the several samples were united 

 and the composite sample was subjected to analysis. 



The samples analyzed group themselves as follows: 291 complete 

 fertilizers, furnishing phosphoric acid, potash and nitrogen; 1 dis- 

 solved bone, furnishing phosphoric acid and nitrogen; 60 rock- 

 and-potash fertilizers, furnishing phosphoric acid and potash; 49 

 acidulated rock phosphates, furnishing phosphoric acid only; 44 

 ground bones, furnishing phosphoric acid and nitrogen; 5 miscella- 

 neous fertilizers, which group includes potash salts, nitrate of soda 

 and other substances not readily classified under the foregoing heads. 



The determinations to which a complete fertilizer is subjected are 

 as follows: (1) Moisture, useful for the comparison of analyses, for 

 indication of dry condition and fitness for drilling, and also of the 

 conditions under which the fertilizer was kept in the warehouse. (2) 

 Phosphoric acid — total, that portion soluble in water, and, of the 

 residue, that portion not soluble in warm ammonium citrate solution 

 (a solution supposed to represent the action of plant roots upon 

 the fertilizer), which is assumed to have little immediate food 

 value. By difference, it is easy to compute the so called "reverted" 

 acid, which is the portion insoluble in water but soluble in the citrate. 

 The sum of the soluble and reverted is commonly called the "avail- 

 able" phosphoric acid. (3) Potash soluble in wa^^e^, — most of that 

 present in green sand marl and crushed minerals, and even some of 

 that present in vegetable materiaUs' such as cotton-seed meal, not 

 being included because insoluble in water even after long boiling. (4) 

 Nitrogen — this element is determined by a method which simply ac- 

 counts for all present, without distinguishing between the quantities 

 present in the several forms of ammonium salts, nitrates or organic 

 matter. (5) Chlorin; this determination is made to afford a basis for 

 estimating the jn'oportion of the potash that is present as chlorid or 

 muriate, the cheaper source. The computation is made on the as- 

 sumption that the chlorin present, unless in excess, has been intro- 

 duced in the form of muriate of potash: but doubtles.% there are occa- 

 sional exceptions to this rule. One part of chlorin combines with 



