44 
Joiirnal of Agricultural Research * 
Vol. XXVIII, No. 1 
Cyanamid failed to show any nitrification during the first 70 days but actually 
depressed the nitrate formation from the soil organic matter. At the end of 84 
days there was a 12.77 per cent conversion and after 112 days the maximum of 
only 66.65 per cent was reached. From subsequent experiments (Table IV) with 
the same or larger quantities of cyanamid it appears probable that the presence 
of the calcium carbonate had a deleterious effect upon the rate of nitrification of 
this material. 
AMMONIFICATION AND NITRIFICATION OF VARYING QUANTITIES OF TREATED AND 
UNTREATED CYANAMID 
These experiments were made to determine whether hydrating and oiling 
cyanamid has any effect upon its rate of decomposition and nitrification and hence 
upon its value as a fertilizer. The treatment given the cyanamid was the same 
as ordinarily used for commercial cyanamid and consisted of hydration with 8 per 
cent water and the addition of 3.5 per cent of mineral oil. 
It was also desired to determine the maximum quantity of cyanamid which 
may be used without seriously affecting nitrification. Since the soil showed a 
high nitrifying efficiency without the addition of calcium carbonate none of the 
latter material was used. 
In making the analyses, if urea was found to be present two samples of soil were 
analyzed, one for ammonia, nitrate, and urea and the other for combined cyanamid 
and dicyanodiamid. Only a qualitative test was made for cyanamid because of 
the great difficulty experienced in washing the silver precipitate free of all traces 
of ammonia. When urea was absent all of the analyses were made on one sample 
of soil. The results are given in Table IV and in part in figure 2. The data 
used in plotting the graph were those secured with oiled and hydrated cyanamid. 
. Table III .—Compar ison of rates of nitrification of cyanamid, urea, and ammonium 
sulphate 
16 days 
28 days 
42 days 
| 70 days 
1 
Treatment (20.9 
mgm. N per 100 
gm. soil) 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
| 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
Soil alone___ 
4.31 
5.51 
6.91 
8.65 
Cyanamid.. 
a. 48 
0.00 
.74 
0.00 
1.23 
0.00 
6.70 
0.00 
Urea.... 
11.31 
7.00 
24.71 
19.20 
25.86 
18.95 
27.13 
18.48 
Ammonium sulphate. 
10.64 
6.33 
23.01 
17.50 
25.26 
18.35 
26.88 
18.23 
84 days 
! 
112 days 
154 days 
210 days 
Treatment (20.9 
mgm. N per 100 
gm. soil) 
Nitrate 
mgm. N 
1 
Increase 
over 
control 1 
mgm. 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
Nitrate 
mgm. N 
Increase 
over 
control 
mgm. 
Soil alone .. 
8.66 
9.83 
12.50 
13.75 
Cyanamid.. 
11.33 
2.67 | 
.. __| 
23.76 
13.93 
25.58 
13.08 
27.28 
13. 53 
Urea_ _ 
28.11 
18.28 
29.85 
17.35 
30.78 
17.03 
Ammonium sulphate. 
27.39 
17.56 
1 
29.65 
17.15 
30.27 
16.52 
! 
<* Qualitative tests showed absence of cyanamid nitrogen. 
