For instance, Hall quotes from the Rothamsted experiments
to the effect that in 1879, which was a wet year (41 inches), the
wheat crop yielded 38 pounds of grain for every 100 pounds of straw;
whereas, in 1893, which was a dry year (23 inches), the wheat crop
yielded 95 pounds of grain to every 100 pounds of straw. The Utah
station likewise has established the same law under arid conditions.
In one series of experiments it was shown as an average of three
years' trial that a field which had received 22.5 inches of
irrigation water produced a wheat crop that gave 67 pounds of grain
to every 100 pounds of straw; while another field which received
only 7.5 inches of irrigation water produced a crop that gave 100
pounds of grain for every 100 pounds of straw. Since wheat is grown
essentially for the grain, such a variation is of tremendous
importance. The amount of available water affects every part of the
plant. Thus, as an illustration, Carleton states that the per cent
of meat in oats grown in Wisconsin under humid conditions was 67.24,
while in North Dakota, Kansas, and Montana, under arid and semiarid
conditions, it was 71.
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