78 
Journal of Agricultural Research 
Vol. XXIV, No. t 
Tabi^E XI .—Percentage of plants developing yellows when planted in the field on different 
dates during the season 
Date of plantine. 
May 25. 
June 21. 
June 27. 
July 14. 
July 26. 
Aug. 18. 
Sept. 22 
1917. 
Apr. 6.. 
May 8.. 
June 18. 
June 30. 
July 14- 
July 30. 
Aug. 6.. 
Aug. 12. 
Aug. 20. 
Sept. 7. 
Sept. 16 
1919. 
Date of 
observation. 
Number 
of days 
between 
time of 
planting 
and final 
observa¬ 
tion. 
Total number of plants. 
Percentage of yellows. 
Wisconsin 
Hollander. 
Commercial 
Hollander. 
Wisconsin. 
Hollander. 
Commercial 
Hollander. 
June 
27 
33 
100 
100 
0 
5 
July 
II 
20 
ICO 
100 
15 
57 
July 
18 
21 
100 
100 
22 
70 
Aug. 
4 
21 
140 
104 
96 
97 
Aug. 
20 
25 
89 
205 
94 
94 
Sept. 
8 
21 
400 
120 
48 
48 
Oct. 
8 
16 
100 
100 
0 
0 
May 
8 
32 
200 
200 
0 
0 
June 
12 
35 
200 
200 
35 
45 
Juy 
14 
26 
256 
173 
64 
92 
July 
25 
25 
I9I 
96 
94 
96 
Aug. 
6 
23 
III 
93 
100 
100 
Aug. 
22 
23 
269 
140 
97 
100 
Aug. 
28 
22 
210 
266 
96 
97 
Sept. 
16 
35 
390 
360 
100 
100 
Sept. 
16 
26 
28 
131 
100 
100 
Sept. 
27 
20 
152 
134 
53 
70 
Oct. 
8 
22 
213 
280 
0 
0 
INFI<UENCE OF SOIL MOISTURE UPON THE OCCURRENCE OF YELLOWS 
IN CABBAlOE SEEDLINGS 
EXPERIMENTAL methods 
The experiments for measuring the influence of soil moisture upon the 
occurrence of yellows were conducted during the winter of 1918 and the 
spring of 1919 simultaneously with, and under the same atmospheric 
conditions as, the soil-temperature experiments. The same kind of soil 
and receptacles were used, but no cinders were placed on the bottom of 
the receptacles. The moisture-holding capacity of the soil was found by 
means of 5 by 20 cm. tubes to be 46 per cent. When based upon wet 
weight, this gave approximately 31 per cent moisture. 
The moisture content of the soil was kept constant during the experi¬ 
ments through the use of one Livingston cylindrical auto-irrigator, 5 
by 15 cm., in each receptacle. The cup was imbedded vertically in the 
soil, and the water reservoirs were so placed that the moisture content 
became adjusted at 14.5, 19, 23, and 26 per cent, respectively, in the four 
sets of duplicate receptacles. The receptacles with 14.5 per cent moisture 
were kept in the series for only about two weeks when the water columns 
broke and they were not restored in time to keep them in the series. 
Moisture determinations were made just before tide seed was planted 
and at the conclusion of the experiment. The percentage of moisture 
at the conclusion was only a few tenths of i per cent lower than at the 
beginning. The soil temperature was kept constant at 22° to 23® C. 
throughout the experiment. 
