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ANNUAL REPORT OF THE Off. Doc. 



FERTILIZER ANALYSES JANUARY 1, TO AUGUST 1, 1907. 



Since January 1, 1907, there have been received from authorized sampling 

 agents fifteen hundred and ninety-nine fertilizer samples, of which six hundred 

 and two were subjected to analysis, the remainder being rejected either because 

 they represented brands analyzed last season, it being impracticable to analyze 

 all brands received, or because they were regarded as not certainly representa- 

 tive of the brand whose name they bore. Preference is given to those which 

 have not been so recently analyzed. In certain cases when two or more sam- 

 ples representing the same brand were received, equal portions from the sev- 

 eral samples were united, and the composite sample was subjected to analysis. 

 The samples analyzed group themselves as follows: 424 complete fertilizers, 

 furnishing phosphoric acid, potash and nitrogen; 6 dissolved bones, furnishing 

 phosphoric acid and nitrogen; 103 rock-and-potash fertilizers, furnishing phos- 

 phoric acid and potash; 41 acidulated rock phosphates, furnishing phosphoric 

 acid only; 27 ground bones, furnishing phosphoric acid and nitrogen, and one 

 miscellaneous sample, 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 con- 

 dition and fitness for drilling, and also of the conditions under which the fer- 

 tilizer was kept in the warehouse. (2) Phosphoric acid — total, that portion 

 soluble in water, and of the residue, that portion not soluble in warm ammonia 

 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 dif- 

 ference, 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 re- 

 verted is commonlly called the "available" phorphoric acid. (3) Potash sol- 

 uble in water — most of that present in green sand marl and crushed minerals, 

 and even some of that present in vegetable materials such as cotton-seed meal, 

 not being included because insoluble in water even after long boiling. (4) Nitro- 

 gen — This element is determined by a method which simply accounts for all 

 present, without distinguishing between the quantities present in the several 

 forms of ammonium salts, nitrates or organic matter. (5) Chlorin — this deter- 

 mination is made to afford a basis for estimating the proportion of the potash 

 that is present as chlorid or muriate, the cheapest source. The computation is 

 made on the assumption that the chlorin present, unless in excess, has been in- 

 troduced in the form of muriate of potash; but doubtless there are occasional ex- 

 ceptions to this rule. One part of chlorin combines with 1.326 parts of potash 

 to form the pure muriate; knowing the chlorin, it is, therefore, easy to com- 

 pute the potash equivalent thereto. (7) In the case of ground bone, the state 

 of sub-division is determined by sifting through accurately made sieves; the 

 cost of preparation and especially the promptness of action of bone in the 

 soil depends very largely on the fineness of its particles the finer being much 

 more quickly useful to the plant. 



The law having required the manufacturer to guarantee the amount of cer- 

 tain valuable ingredients present in any brand he may put upon the market, 

 chemical analysis is employed to verify the guaranties stamped upon the fer- 

 tilizer sacks. It has, therefore, been deemed desirable in this report to enter 

 the guaranty filed by the manufacturer in the office of the Secretary of Agri- 

 culture, in such connection with the analytical results that the two may be 

 compared. An unfortunate practice has grown up among manufacturers of so 

 wording the guaranty that it seems to declare the presence in the goods of an 

 amount of a valuable constituent ranging from a certain minimum to a much 

 higher maximum; thus, "Potash, 2 to 4 per cent." is a guaranty not infre- 

 quently given. In reality, the sole guaranty is for 2 per cent. The guaranteed 

 amounts given for each brand in the following tables, are copied from the guar- 

 anties filed by the maker of the goods with the Secretary of Agriculture, the 

 lowest figure given for any constituent being considered to be the amount 

 guaranteed For compactness and because no essentially important fact is sup- 

 pressed thereby, the guaranties for soluble and reverted phosphoric acid have 

 not been given separately, but are combined into a single guaranty for avail- 

 able phosphoric acid; in cases where the maker's guaranty does not specifically 

 mention available phosphoric acid, the sum of the lowest figures given by him 

 for soluble and reverted phosphoric acid is used. The law of 1879 allowed the 

 maker to express his guaranty for nitrogen either in terms of that element or 

 in terms of the ammonia equivalent thereto; since ammonia is composed of 

 tree parts of hydrogen and fourteen parts of nitrogen, it is a very simple mat- 

 ter to calculate the amount of cne, when the amount of the other is given; the 



