452 ANNUAL REPORT OF THE Off. Doc. 



FERTILIZERS ANALYSES AUGUST 1 TO DECEMBER 31, 1914 



Since August 1, 1914, there have been received from authorized 

 sampling agents eleven hundred and eighty-four fertilizer samples, of 

 which four hundred and lifty were subjected to analysis. Prefer- 

 ence was given to those which have not been recently analyzed. In 

 cases where two or more samples representing the same brand were 

 received, equal portions from several samples were united, and the 

 comi)osite sample was subjected to analysis. 



The samples analyzed group themselves as follows: 281 complete 

 fertilizers, furnishing phosphoric acid, potash and nitrogen 2 dis- 

 solved bones, furnishing phosphorous acid and nitrogen ; 99 rock-and 

 potash fertilizers, furnishing phosphoric acid and potash; 38 acidu- 

 lated rock phosphates, furnishing phosphoric acid only; 23 ground 

 bones, furnishing phosphoric acid and nitrogen, and 7 miscellaneous 

 samples, which group includes substances not properly 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 and insoluble; the latter is, that portion not 

 soluble in water nor 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 "available" phosphoric acid. (3) 

 Potash soluble in water — most of that present in green sand marl and 

 crushed minerals, and even some of that present in vegetable mate- 

 rials such as cotton-seed meal, not being included because insoluble 

 in water even after long boiling. (4) Nitrogen — This element is 

 determined in such manner as to ascertain its total quantity and 

 also, beginning with the present season, the quality of the organic 

 nitrogenous material present in the finished fertilizer. The fertilizer 

 is washed thoroughly with water, which removes the nitrates, am- 

 monium salts and almost all of the cyanamid nitrogen, and the 

 soluble organic nitrogenous materials. These are not separately de- 

 termined, but are grouped under the name "icater-HoluMe nitrogen." 

 The quantity of water-insoluble nitrogen is directly determined, and 

 by difference between its amount and the total nitrogen, the water- 

 soluble nitrogen is calculated. Another portion of water-insoluble 

 material* is treated with alkaline potassium permanganate, which 

 attacks the nitrogenous organic substances present, and converts the 

 more active portion into ammonia, which is distilled off, determined, 

 and its nitrogen calculated as "active insoluMe nitrogen." The "Inac- 

 tive insoln'ble nitrogen" is then computed by subtracting the active in- 

 soluble from the total insoluble nitrogen. The term "available nitro- 

 gen" as used in this report, is the sum of the water-soluble and the ac- 

 tive insoluble nitrogen. It is equivalent to the total nitrogen less the 

 inactive insoluble nitrogen. In high grade organic nitrogenous mater- 

 ials, among which, from its behavior with this treatment, must be 

 included horn meal, the percentage of inactive nitrogen in the insolu- 



*This dftermination has been omitted in all cases where the insoluble nitrogen is only .2 per 

 cent, or less. 



