1118 
Joumal of Agricultural Research 
' Vol. XXVIII, No* 11 
Table I.— Comparison of nitrate formation in soils receiving phosphorus nitride 
and ammonium sulphate 
Treatment 
Control.. 
Ammonium sulphate 
Do.. 
Do__ 
Phosphorus nitride _ _ 
Do.. 
Do.. 
Mgm. N 
added 
per 100 
gm. of soil 
Nitrate 
nitrogen 
Average 
Increase 
over con¬ 
trol 
19 days 
Mgm. 
3.35 
3.14 
2.58 
.61 
.50 
.49 
Nitrate 
nitrogen 
Average 
Increase 
over con¬ 
trol 
35 days 
56 days 
Mgm. 
7.44 
7.88 
11.33 
11.84 
16.54 
17.37 
26.05 
26.72 
8.40 
8.40 
8.14 
8.14 
8.14 
8.02 
Mgm. 
3.93 
9.30 
18.73 
.74 
.48 
.42 
75 days 
Control__ 
Ammonium sulphate. 
Do.. 
Do-...__ 
Phosphorus nitride... 
Do___ 
Do__ 
0 
f 8.68 
\ 9.30 
} 8.99 
5 
/ 14.89 
\ 14.08 
} 14.48 
10 
/ 18.61 
\ 19.30 
} 18.96 
20 
f 28.94 
\ 27.42 
} 28.18 
5 
/ 8.98 
\ 8.40 
| 8.69 
10 
/ 8.98 
\ 8.68 
} 8.83 
20 
/ 8.98 
\ 8.98 
} 8.98 
5.49 
9.97 
19.19 
-.30 
-.16 
-. 01 
8.40 
8.68 
14.08 
13.36 
18.61 
19.30 
28.16 
27.42 
8.40 
8.54 
8.54 
8.68 
7.89 
8.14 
5.18 
10.42 
19.25 
-.07 
.07 
-.54 
It will be observed from the table that the addition of phosphorus nitride to 
soil, maintained under optimum conditions for nitrification, did not markedly 
affect the nitrate content. During the first month there was a slight increase 
but later a decrease in nitrates. This initial slight increase may have resulted 
from the nitrification of the phosphorus nitride or, on the other hand, this material 
may have merely stimulated the nitrification of the soil organic matter. It is 
impossible to state which of the two explanations is the correct one. However, 
it is certain, judging from the limited amount of data here presented, that the 
nitrogen in phosphorus nitride is not readily converted into nitrates and since 
plants for the most part require nitrate nitrogen for their best growth, it is very 
improbable that phosphorus nitride would supply that demand. 
