246 
Journal of Agricultural Research 
Vol. V, No. 6 
the variety planted. Unlike the barley, this grain crop showed decided 
differences in development upon the different rations during its growth, 
as shown in Plate XXII, figure 3. In Table VIII are given the average 
yields of the thrashed crop in the usual manner, the husks being care¬ 
fully removed from the seed. 
Table VIII .'—Average weights (in grams) of the air-dried oat crop 
Treatment. 
Straw. 
Grain. 
Weight. 
Relative 
yields 
when con¬ 
trol— 100. 
Weight. 
Relative 
yields 
when con¬ 
trol—100. 
1. 
Control. 
28. s 
IOO 
2 - 5 
IOO 
2 . 
Complete fertilizer. 
56.0 
197 
5-0 
200 
3 - 
Complete fertilizer+sodium sulphate. 
57*5 
202 
8.5 
340 
4 - 
Complete fertilizer-(-calcium sulphate_ 
54-5 
I 9 1 
8.5 
340 
5 - 
Sodium sulphate only. 
19* 5 
68 
2 * 5 
IOO 
6 . 
Calcium sulphate only. 
19. 0 
67 
2. 5 
IOO 
7 - 
Sulphur only. 
2 3 - 5 
82 
3 - 5 
140 
The statements previously applied to the limited amount of data on 
barley also apply to the oats. So far as the preceding table is concerned, 
however, it indicates, as in the case of barley, no appreciable effect of 
sulphates upon the development of straw when they supplement the 
usual complete-fertilizer ration. Sulphur and sulphates alone even 
depressed the yield of straw as compared with the control crops. 
In the case of the grain, the application of sulphur and sulphates alone 
did not increase the yield as compared with the controls, although it 
increased the ratio of grain to straw. The crops receiving complete 
fertilizer indicate a marked stimulating effect of sulphates upon seed 
production in this crop. Those crops receiving sulphates in addition to 
a complete fertilizer produced 70 per cent more seed than those receiving 
complete fertilizer only. 
The data from these two crops of the Gramineae family have shown 
a marked response of these plants to the application of sulphates by 
increased seed production. From these records it appears that under 
present common methods of fertilization these grain crops may fre¬ 
quently reach a maximum production of straw, but that the capacity 
of this yield of straw to produce seed may be greatly enhanced by the 
addition of calcium sulphate or sodium sulphate to the so-termed com¬ 
plete-fertilizer ration. In future investigations the writers plan to 
determine whether the indications here obtained with the Gramineae 
express a general and fundamental sulphur requirement of this family of 
plants. 
The influence of the concentration of the soil sulphates on the sulphur 
content of plants has already received consideration (9), but it will not 
