22 BULLETIN 158, U. S. DEPARTMENT OP AGRICULTURE. 



of the soil into ammonia and nitrate, which in turn are used by the 

 plant. The soluble nitrogen of base goods should therefore be in a 

 more readily available form than the nitrogen of dried blood or 

 other nitrogenous fertilizers which are entirely of a protein nature. 



THE CHEMICAL PRINCIPLES UNDERLYING THE UTILIZATION OF 

 NITROGENOUS TRADE WASTES. 



In these days of conservation and scientific management more 

 and more attention is being paid to the trade wastes from the various 

 industries and to the municipal scrap heaps. Things which were 

 formerly thrown away are now often made to pay for the entire cost 

 of production. After the resources of the chemist and inventor have 

 failed in finding any other use for some industrial waste, if it 

 be of a nitrogenous nature, the fertilizer industry is turned to as a 

 last resort. Here, however, all is not plain sailing since many of 

 these nitrogenous substances are of such a nature that the nitrogen 

 is said to be "unavailable" for plant use, that is, the substance is 

 of such a nature that it is not readily decomposed by the natural 

 agencies at work in the soil, so that for the purpose of plant nutri- 

 tion the nitrogen of such substances is worthless or of little value. 

 In order to render available this type of nitrogenous material many 

 different kinds of treatment have been suggested, and the patent 

 literature abounds in inventions of this sort. 



It has already been stated that in order that the plant may make 

 use of the nitrogen of even high-grade organic fertilizers, it is necessary 

 for the proteins therein to be at least partially decomposable by the 

 biological and biochemical agencies of the soil. The low-grade organic 

 nitrogenous fertilizers resist decomposition by these biological and bio- 

 chemical soil agencies, and their nitrogen is therefore considered to be 

 less available for plant use. The guiding idea behind the processes 

 proposed for the treatment of trade wastes, which will not decompose 

 easily in the soil as such, is to change the nitrogen compounds con- 

 tained in them in such a way that ammonia is formed and that their 

 decay in the soil is more rapid. 



Much of the nitrogenous materials in trade wastes is of a protein 

 nature, since the products from which these wastes are derived are 

 either of animal or vegetable origin. Such is the case with the wastes 

 Used in the manufacture of base goods. It has been shown that by 

 the process used in the case of this fertilizer the nonavailable nitroge- 

 nous materials have been made highly available, not only because the 

 nitrogen compounds can be ammonified quickly in the soil, but also 

 because these compounds are directly utilizable by plants. This 

 change in the nature of the nitrogen compounds has been brought 

 about by the partial hydrolysis of the proteins contained in the various 

 trade wastes used in the manufacture of the fertilizer. When proteins 



