544 
AMERICAN JOURNAL OF BOTANY 
[Vol. io. 
of the reaction. The soil was then inoculated and planted as before with 
Chalk’s Early Jewel tomato seed. 
Germination of the seed in flats no. iA was apparently normal, occurring 
at the same time as that in the other flats. The plants grew well and ap¬ 
peared thrifty, though they never attained quite the size of the plants in the 
other flats. The reaction of the soils at the time of planting the seed, and 
the results of the experiment are given in table 2. 
Table 2. Influence of Soil Reaction on the Development of Fusarium Wilt of Tomato Seed¬ 
lings 
Type of Soil 
Number of 
Flat 
Reaction of 
Soil, pH 
No. Plants 
Died in 
Four Weeks 
No. Plants 
not Wilted 
but Found 
Infected 
No. Plants 
in Flat 
Percent¬ 
age of 
Plants Dis¬ 
eased 
Percent¬ 
age of 
Plants 
Dead 
Sandy loam. 
I A 
5-0 
44 
0 
44 
100.0 
100.0 
I 
5-8 
22 
14 
49 
73-4 
45-0 
u u 
2 
6.4 
21 
IO 
50 
62.0 
42.O 
3 
6.8 
21 
9 
50 
60.0 
42.O 
u u 
4 
7.0 
l6 
7 
50 
u u 
5 
7.0 
l6 
8 
50 
47.0 
32.O 
u u 
6 
.7-2 
9 
6 
50 
30.0 
18.0 
Silt loam. 
1 A 
5-0 
33 
1 
35 
97.1 
94-3 
a U 
1 
5-6 
30 
18 
50 
96.0 
60.0 
a u 
2 
5-8 
22 
14 
48 
75-0 
46.0 
a u 
3 
6.0 
13 
n 
47 
5L0 
27.7 
11 u 
4 
6.4 
14 
10 
50 
48.0 
28.0 
n 11 
5 
6.8 
12 
20 
50 
64.0 
24.0 
It will be noted that the soil in flats nos. 4 and 5 of the sandy-loam series 
gave the same reaction; consequently the results were combined. The 
soil in all the flats tended to be somewhat more acid than in the previous 
tests, though, with the exception of the two flats noted, a good gradation was 
secured. From these tests it would appear that calcium carbonate alone is 
not effective in producing a marked alkaline reaction in the soil, at least 
unless excessive amounts are added, or unless it is allowed to act for a con¬ 
siderable period of time. 
It is interesting to note in this connection that Plummer (18), in reporting 
the hydrogen-ion concentration of soils as determined by means of the hydro¬ 
gen electrode, gives an example of a soil having as alkaline a reaction as 
pH 9.7. This soil, however, is stated to be a Cumberland loam soil which 
had been treated two years previously with 16,000 pounds of calcium car¬ 
bonate per acre in excess of the Vietch lime-requirement indication. 
The results of this experiment show again the gradual reduction in the 
amount of wilt developing from the acid end to the more alkaline end of the 
series, with one slight exception. In flat no. 5 of the silt series, the total 
percentage of plants found infected is 64. This is greater than that found 
in flats nos. 3 and 4. The percentage of plants which died, however, is 
somewhat less than in the others. 
The experiment was carried out during the month of March. In conse- 
