172 
Journal of Agricultural Research 
Vol. XIV, No. 4 
In order to facilitate comparisons, the average data of Table V were' 
plotted on triangular diagrams in the same manner as were the dry- 
weight yields. The corresponding diagrams of the two series thus 
obtained were then compared and a comparison was also made with the 
corresponding yield diagrams (fig. i, 2). These diagrams graphically 
representing the average data of Table V are not here given, but the 
chief points brought out by these comparisons are presented below: 
A.—Relation of Transpiration to Yields 
A comparison of the transpiration diagrams of series A with the cor¬ 
responding yield diagrams shows the main areas indicating high trans¬ 
piration rates, and also those denoting low rates, to occupy positions 
corresponding fairly well, though not absolutely, with the areas of high 
and of low yields, respectively, both of tops and of roots. In series B 
there is equally good agreement between transpiration and yields of 
tops and of roots, both for the areas of high yields and for those of low 
yields. It is thus clear that, in general, high transpiration corresponds 
to high yields of tops and of roots for each of the two developmental 
periods represented by series A and series B. It is to be emphasized, 
however, that there is no agreement between the areas of high and low 
values on the corresponding transpiration diagrams of the two series. 
This is a clear indication that the relation between the various salt pro¬ 
portions and transpiration is as widely different with respect to the two 
periods of development here considered as is the relation between these 
salt proportions and the yields, either of tops or of roots. 
B.—Relation of Water Requirements to Yields 
A study of the five triangular diagrams representing the water require¬ 
ment data in Table V brings out several interesting relations. Thus, 
in series A, a definite relation is shown between the water requirements 
of tops and top yields and also between the water requirements of roots 
and root yields. On the diagram representing water requirements of 
tops, in this series, the areas of high values correspond to the areas of 
low values on the diagram of top yields, while the regions of low water 
requirement values correspond to the areas of high top yields. These 
relations are shown to hold equally well between the water requirements 
of roots and root yields. In series B the diagrams representing the 
water requirements of tops and of roots, when compared with the corre¬ 
sponding yield diagrams, show a marked tendency toward the same 
relations. This is particularly true with respect to the relations be¬ 
tween low water requirements and high yields, both for tops and for 
roots, although the agreements are not so exact as they are in series A. 
There is, however, no detailed agreement between the areas of low 
yields and those of high water requirements. 
