CLIMATE AND COMPOSITION 271 



wheat from the humid area. The average protein 

 content of the wheat of the United States is a httle 

 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 con- 

 ducted 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 onlj^ 9.81 per cent 

 of protein. Quotations might be multii^lied con- 

 firming 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 composi- 

 tion of plants. Carleton observed that the same 

 varieties of wheat grown at Nej^hi, Utah, contained 

 16.61 per cent protein ; at Amarillo, Texas, 15.2.5 per 

 cent; and at McPherson, Kansas, a humid station, 

 13.04 per cent. This variation is undoubtedly due 

 in part to the varying annual precipitation but, also, 

 and in large part, to the varying general chmatic 

 conditions at the three stations. 



