Feb. 9, 1924 
Effect of Fertilizers on Stem Rust of Wheat 
35i 
appearance of the plants in any of the plats except those which had 
been fertilized with nitrogen. 
On July 1, stem rust began to appear on Haynes Bluestem. None had 
yet appeared on Iumillo. By July 27, Haynes Bluestem was uniformly 
infected with stem rust, but there were no apparent differences in the 
degree of infection in the different plats. On August 25, the plants 
were practically ripe and final observations were made. The results are 
given in Table III, which also is a diagram of the plats and their treat¬ 
ment. Figure 2 presents graphically the results from the series of 
seven plats receiving 2,000 pounds of acid phosphate and various other 
treatments. 
Table III.— The effect of commercial fertilizers on the percentages of stem rust on Iumillo 
and Haynes Bluestem wheats; and on the degree of lodging and yield of Haynes Bluestem 
in iqi 5 on University Farm , St. Paul, Minn. 
Fertilizer. 
Fertilizer, kind and amount (pounds) 
per acre. 
Infection, lodging, and yield. 
Kind. 
Amount 
per 
Sodium 
nitrate. 
None. 
Potassium 
chlorid. 
acre. 
1,000 
500 
250 
1,000 
500 
250 
Per cent stem rust, Haynes Blue¬ 
stem . 
Pounds . 
2 , OOO 
'70 
76 
80 
78+ 
77 
82 
78 
Per cent stem rust, Iumillo. 
IO 
15 
80 
12. 8 
20 
60 
15.8 
20 — 
15 
12 — 
i 5 
Per cent lodging, Haynes Bluestem. 
Bushels per acre, Haynes Bluestem. 
80 
. 5 
O 
16.6 
0 
27.9 
O 
26. 2 
0 
26. 9 
Per cent stem rust, Haynes Blue¬ 
stem . 
(76 
78 + 
80 
18 
60 
14. 1 
80+ 
20+ 
85 
86 
85 - 
Per cent stem rust, Iumillo. 
v 
I, OOO 
20— 
60 
. 8.2 
15 
60 
13-9 
20 
60 
22. 7 
20 
60 
22. 9 
20 
Per cent lodging, Haynes Bluestem. 
Bushels per acre, Haynes Bluestem. 
cd 
f 
00 
O tL 
Tf H 
40 
26.1 
Per cent stem rust, Haynes Blue¬ 
stem . 
r 
a , 
(83- 
85 + 
18 
82 
83+ 
87 
85 - 
88 
Per cent stem rust, Iumillo. 
500 
. 2 3 
20 
25- 
IS 
15 - 
20— 
Per cent lodging, Haynes Bluestem. 
Bushels per acre, Haynes Bluestem. 
< 
40 
6.5 
40 
14-3 
40 
17. 1 
20 
I 9 . I 
0 
19-3 
20 
25*5 
0 
3 i 
Per cent stem rust, Haynes Blue¬ 
stem . 
’80 
82- 
85 + 
83 
M 00 
00 M 
+ 
80+ 
86+ 
Per cent stem rust, Iumillo. 
None. 
22 
22 — 
25- 
25 
iS- 
20 
Per cent lodging, Haynes Bluestem. 
Bushels per acre, Haynes Bluestem. 
00 
40 
16. 2 
0 
19. 8 
O 
22. 8 
0 
20. 7 
0 
21. 4 
0 
20. 5 
It is quite evident from Table III that there is no definite correlation 
between the kind and amount of fertilizers applied and the amount 
of stem rust on the plants. The extreme range in percentage of stem 
rust is from 70 to 88 per cent. It so happens that the lowest percentage 
was in the plat which had received 1,000 pounds of sodium nitrate and 
2,000 pounds of acid phosphate, while the highest percentage was in the 
plat which had received 500 pounds of acid phosphate and 250 pounds 
of potassium chlorid. 9 The heaviest infection, then, was in one of the 
• The figures given always indicate the rate per acre at which the fertilizers were applied; for conven- 
i ence the rate is given rather than the actual amount applied to each square-rod plat. 
