202 
Journal of Agricultural Research 
Vol. VII, No. 4 
ratios are irregular, owing to rainy weather and to the small size of the 
plants. After this period no difference in the transpiration of the two 
crops was observable until after July io, at which time the plants began 
to show signs of ripening through the dying back of the lower leaves. 
There was then a sudden drop in the relative transpiration, followed after 
about two weeks by a gradual increase to harvest time; in other words, 
Galgalos lost proportionately more water than Kubanka in the final 
stages of ripening but less in the early stages of ripening. 
The ratio of the transpiration of Hannchen barley to Kubanka wheat 
decreased gradually throughout the whole period. The same was true 
of Burt oat and spring rye. Swedish Select oat and Kubanka wheat 
showed only slight differences in the relative transpiration rate. Barley, 
rye, and Burt oat made their greatest demand on the soil moisture early 
in the growth season, while the other crops used relatively more water 
near the latter part of the season. 
The graph representing the ratio of Siberian to Kursk millet shows no 
difference in the behavior of these crops. Dakota and Minnesota Amber 
sorghum also show no differences except in the early stages of growth. 
A marked difference is shown in the two varieties of com included in 
the 1914 measurements. The ratio increased gradually throughout the 
season, owing to the fact that Algeria is a late com compared with 
Northwestern Dent. The first crop of Sudan grass grown in the open 
gradually increased its transpiration coefficient with respect to Sudan in 
the inclosure, but no difference was evident in the second crop. 
Alfalfa E23-20-52 and alfalfa E2 3 showed no differences in their 
transpiration response. Cuttings were used in alfalfa 162-98A. The 
plants started more rapidly than the seedlings of alfalfa E23. Not until 
the third cutting was this advantage fully overcome by the crop grown 
from seed; in other words, during the period covered by the first two 
cuttings the transpiration coefficient of alfalfa E23 was gradually in¬ 
creasing compared with that of alfalfa 162-98A. The ratio graphs of 
the same variety inside and outside the inclosure indicate that the plants 
inside grew somewhat more rapidly, the graphs of the second and third 
crops having a downward trend. 
The measurements in 1915 included the whole life period of the plants 
considered (fig. 18). At the beginning and end of the period the amount 
of transpiration was very small, which results in irregularities in the 
ratios. The graph representing the ratio of Galgalos wheat to Kubanka 
wheat corresponds closely with that of 1914, although Kubanka trans¬ 
pired more rapidly than Galgalos in the ripening stages. In 1914 the 
graph indicates a relatively rapid loss from Galgalos at the end of the 
ripening season. Galgalos was rusted badly in 1915, and this may account 
for the comparatively rapid decline in transpiration rate just before 
harvest. 
