3 7° Journal of Agricultural Research voi. xxvn, No. 6 
plats at the Morris substation. The description of the soil at Crookston 
is given in the discussion of methods. Each plat was sown to Marquis 
wheat and no attempt was made to produce artificial epidemics of stem 
rust. Notes on stem rust were taken just before the plants ripened. 
The results for 1918 and 1920 are given in Table XVI. Detailed figures 
are not available for 1919 and 1921. However, there was little observable 
effect of fertilizers on the development of stem rust. At Morris, in 1921, 
the wheat in the phosphate plats grew more vigorously and produced a 
denser stand than that on the other plats. But this seemed to have but 
little effect on the amount of stem rust,due partly to early maturity. The 
stand on manured plats was heavy, but the plants ripened so late that 
there was a slight increase of stem rust. 
The differences between rust percentages in various plats in 1918 are 
not great (Table XVI). When the averages for the three replications 
are made, the differences are not significant. There is a complete lack 
of correlation between the percentage of stem rust on the plants and the 
fertilizers applied to the soil. 
Table XVI. —The percentages of stem rust on Marquis in igi 8 and IQ20 in fertilizer 
plats at Crookston, Minn. 
Plat 
No. 
Fertilizer per acre. 
Percentage of stem 
rust. 
1918. 
1920. 
X 
Control... 
40 
50 
2 
1 ton rock phosphate. 
30 
j 
5 o 
f8 tons manure . 
3 
\ 1 ton rock phosphate. 
[ 35 
50 
A 
8 tons manure . ... 
5 ° 
40 
*T 
J 8 tons manure. 
s 
\48o pounds acid phosphate. 
} 35 
5 ° 
6 
480 pounds acid phosphate. 
35 
5 ° 
7 
Control. 
47 
70 
/ 
8 
1 ton rock phosphate. 
r i 
50 
60 
/8 tons manure. 
1 
9 
\i ton rock phosphate. 
I 50 
15 
10 
8 tons manure. 
45 
25 
[8 tons manure...,. 
11 
\48o pounds acid phosphate. 
| 40 
5 ° 
12 
480 pounds acid phosphate... 
45 
30 
TI 
Control .... .. 
30 
5 o 
x 0 
14 
1 ton rock phosphate... 
O 
, 45 
30 
/8 tons manure... 
15 
\i ton rock phosphate. 
| 40 
20 
16 
8 tons manure ..*. 
45 
40 
(8 tons manure... 
17 
I.480 pounds acid phosphate. 
I 50 
50 
18 
480 pounds acid phosphate.. 
40 
25 
In 1921, there was a wide variation in percentage of stem rust in certain 
individual plats, but in the three replications these differences were not 
consistent, a fact attributed to the very spotted and nonuniform occur¬ 
rence of the rust, so characteristic of the epidemic throughout the State. 
Early in July drought checked the spread of rust, and a uniform epidemic 
