May 31,1924 Experiments with Atmospheric Nitrogen Fertilizers 
975 
cyanamid or sodium nitrate, indicating that the material is slowly made avail¬ 
able. This may explain the good results 4 previously reported, which were ob¬ 
tained with urephos on winter grain crops. In this case the fertilizer was applied 
in the fall and not used to any great extent by the plants until the following 
spring and early summer. 
Table II .—Summary showing relative green weights of wheat 
Norfolk sandy loam 
Chester loam 
Source of nitrogen 
4-8-4 
ratio 
8-8-4 
ratio 
4-8-4 
ratio 
( 
8-8-4 
ratio 
No nitrogen......... 
100 
100 
100 
100 
No fertilizer_______ 
92 
92 
76 
76 
Sodium nitrate_____ 
216 
309 
137 
158 
Calcium nitrate_______ 
224 
290 
131 
157 
Ammonium sulphate..... 
236 
303 
139 
157 
Cyanamid______ 
175 
234 
125 
135 
Cyanamid 75 per cent, calcium nitrate 25 per cent_ 
229 
283 
130 
138 
Cyanamid 50 per cent, calcium nitrate 50 per cent_ 
240 
303 
128 
128 
Cyanamid 25 per cent, calcium nitrate 75 per cent_ 
221 
290 
134 
122 
Guanylurea sulphate___ 
117 
200 
110 
128 
SUMMARY 
The greenhouse experiments reported here, using Norfolk sandy loam and 
Chester loam soils, are too limited in extent to justify general conclusions, but 
do serve as good indications of the relative fertilizer values or toxicity for wheat 
and beans, of the materials studied. These indications may be summarized as 
follows: 
The green weights showed no marked differences between sodium nitrate, 
ammonium sulphate, urea, ammonium nitrate, calcium nitrate, and ammoniated 
superphosphate. In the first experiment cyanamid also gave yields corre¬ 
sponding to ammonium sulphate used as a standard for comparison, but in a 
later experiment with wheat it was less satisfactory. This discrepancy in the 
results with cyanamid used under controlled conditions in the greenhouse 
merely verifies similar or more marked variations noted in the field. 
Urephos was not so satisfactory a nitrogen carrier as the materials mentioned 
in the group above. The fact that from 30 to 35 per cent of its nitrogen is in 
the form of guanylurea is undoubtedly the explanation for the poorer showing. 
Although the results with the light and medium applications were rather good, 
the yields at the largest rate were considerably poorer. 
Guanylurea sulphate is not a suitable nitrogen carrier. In some instances it 
produced fair increases in growth, while in others it either seemed to be inert 
or actually retarded plant growth to a considerable extent. There were some 
indications that the material is slowly made available and might be of use to a 
slow-growing crop, but further experimentation will be necessary to establish 
this point. 
Dicyanodiamide injured the growth of wheat, causing a burning of the tips 
of the wheat blades and a retarding of growth. The injury was even more 
marked on beans, the leaves turning yellow even with the lightest application. 
With the heavy application, growth was very weak and the lower bean leaves 
dropped off. As is usually the case, the toxic effects were most in evidence on 
the lighter soil. 
* Allison, F. E., Braham, J. m., and McMurtrey, J. E. field experiments with atmospheric 
NITROGEN FERTILIZERS. U. S. Dept. Agr. Bui. 1180, 44 p. f illus. 1924. 
