666 ANNUAL REPORT OF THE Off. Doc. 



FERTILIZER ANALYSES JANUARY 1 TO AUGUST 1, 1911 



Since January 1, 1911, there have been received from authorized 

 sampling agents nineteen hundred and sixty-two fertilizer samples, of 

 which seven hundred and thirty-one were subjected to analysis. Pref- 

 erence is 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: 485 complete 

 fertilizers, furnishing phosphoric acid, potash and nitrogen; 6 dis- 

 solved bones, furuishiug phosphoric acid and nitrogen ; 129 rock-and 

 potash fertilizers, furnishing phosphoric acid and potash ; 51 acidu- 

 lated rock phosphates, furnishing phosphoric acid only; 23 ground 

 bones, furnish phosphoric acid and nitrogen, and 37 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; that 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 materials 

 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 accounts for all present, with- 

 out 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 proportion 

 of the potash that is present as chlorid or muriate, the cheaper source. 

 The computation is made on the assumption that the chlorin present, 

 unless in excess, has been introduced in the form of muriate of potash ; 

 but doubtless there are occasional exceptions 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 compute 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 depend very largely on the fineness of its 

 particles, the finer being much more quickly useful to the plant. 



The preceding paragraph sets forth tlie nature of the examinations 

 given to the several classes of fertilizer's under the laws in force 

 prior to the present year. The legislatioai of 1909 has mnde needful, 

 however, some additional tests, ^ec, 4, of the Act of May 1, 1909, pro- 



