OTHER FACTORS INFLUENCING WATER REQUIREMENT. 
71 
harvested October 8. The plants in the remaining four pots were 
harvested December 7. The water requirement of the pots last 
harvested was about 40 per cent higher than those first harvested. 
These results (Table LXI) indicate that the water requirement 
during the later period of growth was greater than that during the 
earlier period of growth. Climatic conditions influence the water 
requirement so profoundly that it is unsafe to draw conclusions 
from this experiment. 
Table LXI. — Effect of length of the growth period on the water requirement of lupine, 
according to Von Seelhorst (1908a, pp. 199-201)} 
Period. 
Number of 
determi- 
nations. 
Dry 
matter. 
Water 
require- 
ment. 
Ail?. 2 to Oct. 8 
8 
4 
Grams. 
310±8 
264±7 
216±5 
Aug. 2 to Dec. 7 
306 ±10 
1 For correction of data, see Von Seelhorst (1909). An error occurs in Von Seelhorst's paper where the 
water requirement for pot 5 is given as 613 instead of 316. 
A uniform correction is applied for evaporation based upon the evaporation from a bare check pot, but 
only 70 per cent of the evaporation loss from the check pot is deducted. 
The probable error includes differences due to previous treatment. One half of the pots for each period 
of growth were fertilized lightly in the spring and the other half heavily in the fall. Half of the pots for 
the short period had previously produced rye and half, potatoes. The same is true for the long-period 
pots, except that barley and potatoes were the previous crops. The experiment was conducted in the larger 
pots described on page 68. 
fest's experiments. 
Fest (1908) determined the water requirement of the bush bean 
at different times during its growth, using 72 pots, each containing 
20 kilograms of soil. Ten beans were planted in each of 70 of the 
pots and 2 were left as checks. Shade was provided for the check 
pots as the crop developed. The shade was a disk of roofing paper 
cut radially inward from the circumference into narrow strips to a 
depth of 10 centimeters. Alternate strips were bent inward more 
or less to obtain the shade desired. Each pot was given 1 gram 
each of potassium, nitrogen, and phosphorus, and 2 grams of calcium 
carbonate. The pots were kept in the plant house during the experi- 
ment. The results (Table LXII) indicate a higher water require- 
ment during the later periods of growth. This may be due to the 
period of growth, but no check was provided against a change in 
climatic conditions during the progress of the experiment. The 
later part of the experiment was conducted during the warmest 
months of the year and this would increase the water requirement. 
For this reason the experiment as conducted does not seem to the 
writers to be conclusive as regards the relative water requirement 
at different stages of growth. 
285 
