with water in a somewhat wasteful manner; that is, they were given
an abundance of water, and used the largest quantity possible 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 employed. 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.

The water in the large bottle would be required to produce the grain
in the small bottle.

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, approximately 750 pounds of water are required
in an arid district for the production of one pound of dry matter.
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 interested in
dry-farming, it can be used with safety.

Crop-producing power of rainfall

If this conclusion, that not more than 750 pounds of water are
required under ordinary dry-farm conditions for the production of
one pound of dry matter, be accepted, certain interesting
calculations can be made respecting the possibilities of