22 BULLETIN 158^ U. S. DEPARTMENT OF AGEICULTUEE. 
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 ii 
be of a nitrogenous nature, the fertihzer 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 httle 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 
