20 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE. 
Table 8. — Yields per acre of cotton from Section I of field No. 1 in 1920 and 1921. 
Fertilizer ratio. 
Series A.— Ammonium nitrate: 
0-0-0 
Plat. 
0-8-4. 
2-8-4. 
4-8-4. 
8-8-4 
Series B. — Sodium nitrate: 
O-O-O 
0-8-4. 
2-8-4. 
4-8-4. 
8-8-4. 
Series C. — Cyanamid (with acid 
phosphate applied separately): 
0-0-0 
0-8-4. 
2-8-4. 
4-8-4. 
8-8-4. 
Yields of seed cotton (pounds). 
Actual. 
116 
252 
1,296 
952 
1,508 
1,136 
1,836 
1,460 
2,052 
1,884 
164 
324 
1,112 
1,124 
1,364 
1,416 
1,536 
1,760 
2,040 
2,208 
280 
360 
1,504 
1,204 
1,6S4 
1,512 
1,832 
1,888 
1,908 
2,096 
Average. 
Increase 
over 
check. 
1.84 
1,124 
1,322 
1,648 
1,968 
244 
1,118 
1,390 
1,648 
2,124 
320 
1,354 
1,598 
1,860 
2,002 
1921 
Actual. 
524 
244 
506 
648 
92 
1,016 
728 
1,3% 
1,048 
1,620 
1,524 
148 
640 
588 
804 
960 
1,136 
1,308 
1,500 
1,648 
72 
128 
928 
640 
992 
948 
1,160 
1,272 
1,228 
1,704 
Average. 
Increase 
over 
check. 
64 
718 
872 
1,222 
1,572 
128 
614 
882 
1,222 
1,574 
100 
784 
970 
1,216 
154 
504 
S54 
608 
186 
432 
682 
1 The term " fertilizer ratio" used in this and subsequent tables refers to the percentage of NH3, P2O5, and 
K2O per acre, in the order named. Applications were made at the rate of 1,000 pounds per acre. 
Results with corn. — The effects of the various fertilizer treatments 
on corn were quite different from those on cotton. Cyanamid pro- 
duced growth corresponding to that made by sodium nitrate except 
that the early retarding period was a few days longer. However, 
the nitrogen became available about as soon as needed, and no per- 
manent injuries were in evidence. Ammonium nitrate was very 
readily available, as shown by Plate V, Figure 1. The yields are 
given in Table 9. In considering the figures for the unfertilized 
plats it should be borne in mind that these plats received heavy 
applications of nitrogen during the season of 1919, and the effects 
undoubtedly persisted during the following two years. 
The differences between the three sources of nitrogen when used 
as fertilizers for corn were not great when due allowance is made for 
soil variations. The increases in yields obtained with ammonium 
nitrate were usually larger than with sodium nitrate or cyanamid, 
but the actual yields were smaller. This was because the soil was 
very shallow, due to continuous erosion. Cyanamid gave practically 
the same increases as sodium nitrate and seemed to be about as 
effective a source of nitrogen for corn as either of the two nitrate 
forms of nitrogen. 
