Protein and oil in corn : variation by crop years from 1907 to 1972
1977
Earle, F.R.
Information on composition of maize grain, mainly from Illinois and Iowa, was from 6 commercial maize processors and from the University of Illinois programme of selection for high or low protein or oil content; information on maize yield and fertilizer use and introduction of hybrid maize came from USA Department of Agriculture publications, and on temperature and rainfall from Weather Bureau Stations. From 1907 to 1972 the protein content of maize ranged between years from 9.1% in 1951 to 11.9% in 1934. It was about the same in 1937-72 as in 1907-29 but was unusually high in 1930-36; the decrease coincided with introduction of hybrid maize but was not a result of that introduction. There was a relation between high protein content and high July temperature in the hotter but not in the cooler years. There was a slight inverse relation between protein and July rainfall and, in the earlier years, between protein and yield. Oil content, recorded since 1917, ranged between years from 4.0 to 4.9% but no reason for the variation was found. Some of these values are published for each year.
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