May 31,1924 Experiments with Atmospheric Nitrogen Fertilizers 
973 
however, not large but usually within experimental error. The comparatively 
limited data would not justify close distinctions between the values of the differ¬ 
ent forms of nitrogen. It is especially significant that cyanamid, which is ordi¬ 
narily considered very slowly available and of questionable value when used in 
large applications in the field, proved to be very readily available under green¬ 
house conditions when thoroughly mixed with the soil. (See PI. 1, A.) 
The green weights secured with urephos were fairly good, but on the average 
poorer than with the sources of nitrogen discussed above. This was very likely 
due to the high content of guanylurea. Where the latter compound was used 
alone, it showed a marked retarding or toxic effect at the higher application, 
especially with beans, but there were no burning effects or dropping of the leaves 
noticeable. (See PL 1, B.) Where a mixture of urea and guanylurea nitrogen 
were in the approximate proportions found in urephos, the yields were the same 
within experimental error. 
Table I .—Summary showing green weights of beans and wheat grown with various 
sources of nitrogen , expressed on a percentage basis 
Norfolk sandy loam 
Chester loam 
Source of nitrogen 
Beans 
Wheat 
Beans 
Wheat 
FERTILIZER RATIO <*-1-8-4 
No nitrogen_____ 
100 
100 
100 
100- 
Ammonium sulphate...... 
110 
127 
118 
122 
Do.* *.... 
119 
113 
130 
118 
Ammonium nitrate._...__.. 
115 
138 
Ammoniated superphosphate______ 
141 
91 
112 
126 
Cyanamid *_____ 
122 
119 
139 
125 
Urea_____ 
107 
116 
123 
121 
Guanylurea sulphate.... 
99 
103 
101 
101 
Urea 70 per cent, guanylurea sulphate 30 per cent_ 
125 
121 
104 
128 
Urephos_____ 
104 
111 
102 
125 
Dicyanodiamide______ 
92 
86 
121 
99< 
FERTILIZER RATIO—: 
1-8-4 
No nitrogen. ___ 
100 
100 
100 
10O 
Ammonium sulphate____ 
137 
153 
135 
183 
Do.*...... 
174 
142 
158 
186 
Ammonium nitrate... 
144 
133 
206 
Ammoniated superphosphate *..... 
153 
127 
154 
169 
Cyanamid *____ 
139 
179 
127 
158 
Urea_ _ 
m 
135 
138 
162 
Guanylurea sulphate__ 
91 
98 
110 
131 
Urea 70 per cent, guanylurea sulphate 30 per cent... 
128 
148 
139 
172 
Urephos __ __ __ 
143 
171 
Dicyanodiamide........ 
76 
70 
120 
100 
FERTILIZER RATIO—16-&-4 
No nitrogen.... 
Ammonium sulphate___ 
Do.*.... 
Ammonium nitrate___ 
Ammoniated superphosphate c ... 
Cyanamid *... 
Urea... 
Guanylurea sulphate... 
Urea 70 per cent, guanylurea sulphate, 30 per cent. 
Urephos___ 
Dicyanodiamide____ 
100 
100 
100 
100 
231 
246 
298 
353 
238 
217 
300 
352 
280 
167 
266 
342 
264 
157 
304 
428 
260 
270 
278 
349 
255 
262 
282 
329 
77 
108 
71 
175 
215 
192 
223 
325 
187 
182 
311 
42 
44 
80 
96 
• The term fertilizer ratio refers to the percentage of NH3, P3O5, and KjO, in the order named, as is 
customary in fertilizer practice. 
• These pots received calcined phosphate. 
• These pots received an abnormally high percentage of P 3 O 5 . 
