74 
WATER REQUIREMENT OF PLANTS. 
Wollny apparently used but a single pot in the case of each crop. 
His experiments extended through approximately four months. No 
determinations are given regarding the amount of grain produced. 
The ratio of the water transpired to the dry matter x produced in 
Wollny' s experiments is given in Table LXV. 
Table LXV. 
Water requirement of crop plants in Munich, Germany, according to 
Wollny (1877, p. 125). 
Crop. 
Dry 
matter. 
Water re- 
quire- 
ment. 
Crop. 
Dry 
matter. 
Water re- 
quire- 
ment. 
Grams. 
48.1 
6.4 
10.7 
5.3 
6.4 
233 
774 
665 
447 
646 
Grams. 
9.8 
4.9 
5.9 
27.8 
416 
912 
Oats 
843 
Millet 
490 
SORATJER S EXPERIMENTS. 
The data presented by Sorauer (1883) which bear on the water 
requirement of different crop plants are given in Table LXVI. 
Table LXVI. — Water requirement of crop plants in Germany, according to Sorauer 
(1883, pp. 90-91). 
Plant. 
Culture. 
Duration. 
Number of 
determina- 
tions. 
Dry 
matter. 
Water 
require- 
ment. 
Rye 
Water culture 
Days. 
53 
53 
53 
53 
8 
7 
8 
8 
0.144 
.327 
.088 
.104 
413 
Barley 
Whea't . 
do 
....do 
490 
708 
do 
600 
These data are taken from Table XLIII (p. 55), and include the 
two series grown in a weak nutrient solution. The results are not in 
accord either with our results for the four crops or with those of 
Lawes for barley and wheat or with Wollny for oats and barley. 
This may be due to the fact that the plants did not reach maturity. 
HELLRIEGEL S EXPERIMENTS. 
Hellriegel (1883) conducted a series of water-requirement experi- 
ments extending over a period of seven years and including a number 
of crop plants. By a series of ratios Hellriegel has also compared 
the relative water requirement of the crops not grown simultaneously. 
His results for each year are given in Table LXVII and the mean 
values are given in the last column. 
1 It is not clear from Wollny's description whether the term refers to air-dried or oven-dried material. 
285 
