CHEMICAL AND BIOLOGICAL STUDIES WITH CYANAMID 
AND SOME OF ITS TRANSFORMATION PRODUCTS 1 
By K. D. Jacob, Assistant Chemist , F. E. Allison, Soil Biochemist , and J. M. 
Braham, Chief , Chemistry Division , Fixed Nitrogen Research Laboratory , United 
States Department of Agriculture 
INTRODUCTION 
In order for any nitrogenous material to be a satisfactory source of nitrogen 
for a wide variety of plants and under varying soil conditions it is necessary that 
the nitrogen be present either in the nitrate form or be readily attacked by the 
soil flora and converted into nitrates. While many plants can use ammonia and 
certain organic forms*of nitrogen for their synthetic processes, most plants requiie 
at least a portion* of their nitrogen in the form of nitrates. The investigations 
reported here were undertaken in order to obtain data on the rate at which cyanamid 
(calcium cyanamid) and its transformation products are broken down to ammonia 
and the latter oxidized to nitrates in the soil. In addition, the effect of dicy- 
anodiamid and guanylurea on the nitrification of the soil organic matter or 
nitrogenous fertilizers which may be applied has been given consideration. The 
term ammonification is used here in the broader sense to include all of the de¬ 
composition processes from which ammonia is finally obtained. The term 
nitrification covers the oxidation of the ammonia to nitrates with nitrites as an 
intermediate product. 
For convenience this paper has been divided into two parts; the first dealing 
with cyanamid and urea which under normal conditions are transformed into 
compounds which are suitable plant foods; the second with dicyanodiamid, guanyl¬ 
urea, guanidin, and biguanid nitrogen which are less desirable in soils. While 
it is probable that these latter compounds may serve as sources of nitrogen for 
plants in some instances, their value is questionable and some of them, parti¬ 
cularly dicyanodiamid, are harmful. 
In using the term transformation products of cyanamid to include the material 
discussed in Part II, it is not meant to imply that all of them are formed in the 
soil when cyanamid is applied. Whether or not this is true still remains to be 
shown. We'do know that small amounts of dicyanodiamid are commonly formed 
and under unusually bad soil conditions the amount may be large, perhaps 25 
per cent of the original nitrogen. There is little known as to the formation of salts 
of guanylurea, guanidin, and biguanid but it is logical to suppose that small per¬ 
centages of these may appear under certain soil conditions. The uncertainty 
with regard to the appearance of these compounds does not necessarily detract 
from the value of a study of their behavior because they may be found in old 
samples of cyanamid or in fertilizer mixtures containing acid salts with which 
the cyanamid has reacted. 
PREVIOUS INVESTIGATIONS AND DISCUSSION 
CYANAMID AND UREA 
A large number of laboratory and field studies have been reported which deal 
with the changes which cyanamid undergoes in the soil and the response of 
i Received for publication, Jan. 4, 1924. 
Journal of Agricultural Research, 
Washington, D. C. 
( 37 ) 
Vol. XXVIII, No. 1 
April 5,1924 
Key No. R-l 
