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Widtsoe, John Andreas, 1872-1952

"Dry-Farming : a System of Agriculture for Countries under a Low Rainfall"

6 per cent, and in soil containing 70 per cent of water, it
was only 5.2 per cent. Carleton, in a study of analyses of the same
varieties of wheat grown in humid and semi-arid districts of the
United States, found that the percentage of protein in wheat from
the semiarid area was 14.4 per cent as against 11.94 per cent in the
wheat from the humid area. The average protein content of the wheat
of the United States is a little more than 12 per cent; Stewart and
Greaves found an average of 16.76 per cent of protein in Utah
dry-farm wheats of the common bread varieties and 17.14 per cent in
the durum varieties. The experiments conducted at Rothamsted,
England, as given by Hall, confirm these results. For example,
during 1893, a very dry year, barley kernels contained 12.99 per
cent of protein, while in 1894, a wet, though free-growing year, the
barley contained only 9.81 per cent of protein. Quotations might be
multiplied confirming the principle that crops grown with little
water contain much protein and little heat-and fat-producing
substances.
Climate and composition
The general climate, especially as regards the length of the growing
season and naturally including the water supply, has a strong effect
upon the composition of plants.


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