RELATION OF WATER TO DRY MATTER 17 
tion of each pound of dry matter is very much larger 
under arid conditions, as in Utah, than under humid 
conditions, as in Germany or Wisconsin. It must be 
observed, however, that in all of thest experiments 
the plants were supplied with water in a somewhat 
wasteful manner; that is, they were given an abun- 
dance of water, and aged the largest quantity pos- 
sible under the prevailing conditions. No attempt 
of any kind was made to economize water. The 
results, therefore, represent maximum results and 
can be safely used as such. Moreover, the methods 
of dry-farming, involving the storage of water in 
deep soils and systematic cultivation, were not em- 
ployed. The experiments, both in Europe and 
America, rather represent irrigated conditions. There 
are good reasons for believing that in Germany, 
Wisconsin, and Utah the amounts above given can 
be materially reduced by the employment of proper 
cultural methods. 
In view of these findings concerning the water 
requirements of crops, it cannot be far from the truth 
to say that, under average cultural conditions, ap- 
proximately 750 pounds of water are required in an 
arid district for the production of one pound of dry 
matter (Fig. 7). Where the aridity is intense, this 
figure may be somewhat low, and in localities of sub- 
humid conditions, it will undoubtedly be too high. 
As a maximum average, however, for districts inter- 
ested in dry-farming, it can be used with safety. 
Cc 
