24 
BULLETIN 844, U. S. DEPARTMENT OF AGRICULTURE. 
immature pods. For this purpose several volunteer plants growing 
in a meadow were selected. A hole 12 inches square and 14 inches 
deep was dug 8 inches from the crown of one plant, and each evening 
during the experiment 2 gallons of water were poured into the hole. 
The top of the hole was kept covered, so as to check evaporation from 
it as much as possible. Another plant of the same size and growing 
about 15 yards from the watered plant served as a check. On both 
plants many of the flowers and immature buds were aborting at the 
beginning of the experiment. The soil in this field was so depleted 
of moisture that the leaves of the plants wilted during the hottest 
part of the days preceding the experiment. The foliage on the check 
plant wilted each day for the first five days of the experiment. On the 
sixth day 0.96 of an inch of rain fell and four days later 0.23 of an 
inch more. The dropping of the flowers was temporarily checked by 
these precipitations, but owing to the dry, compact condition of the 
soil the rain was not sufficient to check entirely the fall of flowers and 
immature pods. At the beginning of the experiment the racemes on 
both plants were divided into three classes, according to the develop- 
ment of the flowers, and labeled. They were collected and the seeds 
counted as soon as the pods at the bases of the racemes commenced 
to turn brown. Table VIII presents the results obtained. 
Table VIII. — Effect of water upon the seed production of sweet clover when growing 
under droughty conditions at Ames, Iowa, in 1916. 
Stage of development when labeled- 
Plant not watered. 
J Average 
Number ft??™ 
of racemes' Kjjj P| r 
labe ' ed - Thaf 
matured. 
Plant watered. 
Number 
Average 
number of 
ofracemes p£sp« 
matured. 
Increase 
from 
watering. 
Flowers at the base of the racemes just ready to open 
Pods 3 to 6 days old 
Pods 9 to 12 days old 
27.39 
21.13 
15.23 
110 
112 
50 
55.63 
39.81 
29.86 
28.24 
18. 68 
14.63 
The effect of the water was noticeable soon after the first appli- 
cation, as the leaves and flowers on this plant became turgid and the 
anther sacs burst at the proper stage of their development. Very 
few flowers fell after the second day. The water decidedly checked 
the aborting of immature pods, as is shown by the results obtained 
on the racemes which were labeled after the pods had formed. The 
racemes which contained pods 3 to 6 days old when labeled matured 
9.95 pods to the raceme more than those which contained older pods 
at the beginning of the experiment, but this was expected, as most 
of the aborting which caused this difference had taken place before 
the racemes were labeled. As very few pods aborted before they 
were 3 to 6 days old, the difference of 9.95 pods to the raceme in favor 
