Aug. 15, 1921 
Effect of Ammonium Sulphate tipon Plants 
723 
will be observed that there is considerable overlapping of these areas. 
Out of the group of six high-yielding cultures in each series three are 
corresponding cultures and are included in the areas marking high yields 
of tops in both series. These three cultures are T1R1C3, T1R3C3, and 
T3R3C1. The maximum yield from the Tottingham series was produced 
by culture T1R3C3, while the maximum yield from the ammonium- 
sulphate series occurred with culture T1R1C5. A similar comparison of 
the areas of high root yields on the diagram of figure 9 also shows a certain 
amount of overlapping of the areas representing these yields from the 
two series under consideration. The three cultures T1R1C3, T1R3C5, 
T3R1C3 are included in the areas representing high root yields in both 
series. The maximum yields of roots were produced by cultures T1R3C5 
Fig. 9.—Distribution of relative dry-weight values of roots for the best six cultures in each series. 
and T1R1C3 in the Tottingham series and the ammonium-sulphate series, 
respectively. In each of these series, however, the maximum yield of 
tops and that of roots was produced by different cultures. 
A comparison of the diagram of figure 8 with that of figure 9 shows a 
pronounced similarity and very close agreement between the areas 
representing high yields of tops and those representing high root yields 
for the ammonium-sulphate series. Five of the six cultures which are 
included in the areas of high top yields (fig. 8) also appear in the areas of 
high root yields (fig. 9). In the Tottingham series, however, no such 
marked similarity between the areas of high top yields and those of high 
root yields is apparent. In this series only two cultures appear in the 
areas of both high top yields and high root yields, although the detached 
