Nov. 8,1915 Relation of Sulphur Compounds to Plant Nutrition 
243 
point of special interest in these results is the fact that sodium sulphate 
gave quite as good results as calcium sulphate when added to the com¬ 
plete-fertilizer ration. This suggests that we were dealing here with a 
plant more tolerant of the concentrated soil solution than were the legumes 
grown. The radish was also more tolerant of elemental sulphur than 
were any of the legumes, although the growth in its presence was some¬ 
what inferior to that of the control plants. 
Rape (Brassica napus ).—The variety grown was Dwarf Essex. Crop 
A was grown on the usual soil, fresh and completely fertilized except for 
elemental sulphur. Crop B followed crop A on the same soil. The soil 
was refertilized and boxes with elemental-sulphur treatment were added. 
Crop C was grown on fresh-fertilized soil. Crop D followed crop C on 
the same soil and with the same fertilizer applications. The rape crops 
were harvested when the death of the basal leaves indicated the near 
approach of maturity. Data of the weights of the air-dried * rape crops 
are given in Table V. 
Table V .—Average weight (in grams) of air-dried rape crops 
4 Treatment. 
1. Control. 
2. Complete fertilizer. 
3. Complete fertilizer+sodium sul¬ 
phate.. 
4. Complete fertilizer+calcium sul¬ 
phate.. 
5. Sodium sulphate alone. 
6. Calcium sulphate alone. 
7. Sulphur alone. 
Tops. 
Roots. 
Rela¬ 
Rela¬ 
tive 
tive 
Crop 
Crop 
Crop 
Crop 
weights 
Crop 
Crop 
Crop 
Crop 
weights 
A. 
B. 
C. 
D. 
with 
A. 
B. 
C. 
D. 
with 
control 
control 
*■100. 
— 100. 
54 -o 
12.7 
11.6 
15*3 
100 
8*5 
2.0 
2. 7 
100 
80. 5 
29.0 
36.4 
27.7 
188 
11.8 
3*8 
5 *i 
. 
157 
90.0 
30.9 
45.6 
40.9 
222 
12.3 
2.6 
5*3 
154 
78 -5 
32-9 
45*4 
50*0 
221 
12.5 
4*9 
6.3 
181 
59*5 
13*9 
IS* 8 
14*3 
hi 
8.5 
2*3 
2.8 
104 
57*0 
14- 7 
13*5 
13*3 
105 
8.8 
3 *o 
3*3 
115 
13*6 
12.3 
4*2 
32 
3 -1 
2. 6 
44 
It is clearly evident that the addition of sulphates benefited this crop, 
but especially so where they supplemented the complete-fertilizer ration. 
Apparently the demands for sulphur of the higher yields of tops from 
the fertilized plants accentuated the benefits from the sulphates in this 
case (PI. XXII, fig. 1). 
The sulphates of calcium and of sodium were equally efficient for 
rape. In the case of the roots only the calcium sulphate gave beneficial 
results. Possibly the soluble sodium sulphates increased the concentra¬ 
tion of the soil solution to such an extent as to retard the growth of the 
roots. It is well known that in water cultures the roots of plants are 
more sensitive than the tops to such changes in the nutrient medium. 
As in water cultures, so, too, in these soil cultures, it appears that the 
growth of tops and of roots does not proceed parallel. 
