300 ANNUAL IJHPOirrS OF IIEPART.MHXT OF ACPJCULTURE. 



CONCENTRATED FERTILIZERS. 



The priiicipiil iiitiogenous materials that have hitherto been used 

 in the niamifacture of fertilizers are (1) or<j^anic ammoniates, as 

 cottonseed meal, dried blood, and tanka<?e; and (2) inorganic com- 

 pounds, as nitrate of soda, cyaiiamid. and ammonium sulphate. Dur- 

 ing the la.st few years a marked c-liange has taken place in the relative 

 proportions in which these materials have been used in fertilizers. 

 Many of the organic materials which were formerly used only in 

 fertilizers are now extensively used as feed for stock, and as such 

 commaml a price much in excess of that (juoted for a corresponding 

 <iuantity of nitrogen in the inorganic compounds. The result is that 

 the organic ammoniates to-day are hard to obtain for fertilizers, and 

 the future offers no prospects of any later increased production at 

 all ill keeping witli the present rate of increase in the use of fer- 

 tilizers. To supply the increasing demand for nitrogen materials, 

 recourse must theiefore be had to tlie inorganic compounds. 



Under the stress of war conditions the War Department has erected 

 a great nitrogen plant aj; Muscle Shoals, Ala. The primary product 

 made at this plant is calcium cyanamid. This product has been used 

 iis a fertilizer to some extent for a number of years, but on the whole 

 with rather unsatisfactory results. It can only be mixed in small 

 proportions with the ordinary form of acid phosphate without 

 causing reversion of the latter. The Muscle Shoals plant is equipped 

 to convert the nitrogen of the cyanamid into ammonia, which in turn 

 may be changed into the nitrate, sulphate, or phosphate. In this way 

 there ma}' be obtained a neutral compound having properties entirely 

 different from the original cvanamid. The last of the compounds 

 mentioned — ammonium phosphate — has a distinct advantage for use 

 as a fertilizer over the other two, in that it contains two fertilizing 

 elements combined in the same compound. For its preparation there 

 is required phosphoric acid, and it fortunately happens that this is 

 the form in which phosphorus is produced in the new processes that 

 are noAv being developed for the more economical utilization and 

 conservation of our phosphate deposits. 



The attention which this bureau is now giving to the question of 

 phosphoric-acid production is referred to in another section of this 

 report. In previous reports an outline was also given of a new 

 method that was developed by this bureau for the recovery of phos- 

 phoric acid as volatilized from an electric or other furnace, and it 

 has been .shown that the form in which the acid is collected by this 

 process is eminently suited for combining with ammonia such as will 

 he produced at the Muscle Shoals j)lant. This method for collect- 

 ing pliosphorijc acid is now being used by an industrial concern in 

 the South, and another concern is now making preparations to use 

 the same process with the electric furnace in the production of phos- 

 phoric acid on a much larger scale, with a view to its use in the direct 

 combination of ammonia prepared from cyanamid. 



It is thus seen that owing to the present and anticipated future 

 scarcity of fertilizer materials active steps are now being taken for 

 the preparation of new materials of a concentrated nature which 

 have not hitherto been used in fertilizers, or used very little. From 

 a theoretical point of view these materials are admirably suited for 



