2 BULLETIN 158, U. S. DEPARTMENT OF AGRICULTURE. 



enous fertilizers, such as cottonseed meal, dried blood, fish scrap, 

 etc., are being used more and more for feed purposes, and the time 

 can not be far distant when their use as fertilizers will cease to be 

 economic; thus a necessity for other and cheaper fertilizers of this 

 type arises. Coupled with this is the desire of the chemist and the 

 manufacturer to utilize in one way or another all waste products, 

 whatsoever their nature, so that the number and kinds of nitrogenous 

 materials which are used in the manufacture of fertilizers is on the 

 increase. Described in the patent literature and found on the 

 market are a large number of fertilizers which may be characterized 

 as "processed," that is, the crude materials, not in themselves per- 

 missible as fertilizers, are made to undergo some decided chemical 

 change to render them suitable as plant nutrients. It has been 

 found that the { ' availability " of the crude substances is nearly al- 

 ways greatly increased by such processing and that a much larger 

 percentage of the nitrogen in the finished product is soluble in water, 

 although the actual chemical changes produced seem to have re- 

 ceived little attention. The chemical compounds in processed fer- 

 tilizers which are here shown to have direct fertilizer significance 

 have not been determined, other than to show that ammonia is 

 formed during processing and that ammonia is more readily pro- 

 duced from the processed goods. 



Since the wastes from which this type of fertilizer is made contain 

 more or less protein, or proteinlike substances, it seemed quite 

 obvious that the finished fertilizers must contain more or less of the 

 chemical compounds which would arise by such treatment from pure 

 proteins in the laboratory. Since the action on plants of many of 

 this class of compounds has been determined it is evident that the 

 finding of such compounds in the fertilizers would throw much fight 

 on the question of the " availability " of the nitrogen in the fer- 

 tilizer itself. 



BASE GOODS A TYPE OF PROCESSED FERTHIZER. 



For a chemical study of processed fertilizers a sample of "wet- 

 mixed" or "base goods" fertilizer was chosen as a representative of 

 this type of fertilizer material. The base goods was obtained directly 

 from the factory for use in this investigation. This fertilizer is made 

 by the treatment of various trade wastes and refuse, such as hair, gar- 

 bage tankage, leather scraps, etc., with rock phosphate and the 

 requisite amount of sulphuric acid. These materials are mixed to- 

 gether in a "den" and the resulting mass is allowed to stand for sev- 

 eral days, until it is cool enough to be conveniently handled. In the 

 course of the reaction the mass reaches a temperature approximating 

 100° C, and the identity of the original substances is almost or en- 

 tirely lost. Under these conditions it is certain that more or less 



