230 IRRIGATION PRACTICE 



the fall, it grows partly in the fall, freezes down, and then 

 grows again early in the spring, before the spring wheat 

 is planted. Fall wheat has, therefore, a longer growing 

 period than has spring wheat, and there is more water 

 available for fall than for spring wheat. Consequently 

 winter wheat contains a smaller percentage of protein 

 than does spring wheat. In an experiment continued 

 eight years, it was found that fall-sown wheat contained 

 15.75 per cent of protein, whereas spring-sown wheat 

 contained 16.85 per cent of protein. Similar differences 

 have invariably been found when contrasting spring- 

 grown and fall-grown grain. 



REFERENCES 



JONES, J. S., and COLVER, C. W. The Composition of Irrigated and 

 Non-Irrigated Fruits. Idaho Experiment Station, Bulletin 

 No. 75 (1912). 



LE CLERC, J. A. A Comparison of Irrigated and Non-Irrigated 

 Wheat. United States Department of Agriculture, Yearbook 

 for 1906, p. 199. 



LEWIS, C. J., KRATJS, E. J., and REES, R. W. Orchard Irrigation 

 Studies in the Rogue River Valley. Oregon Experiment Sta- 

 tion, Bulletin No. 113 (1912). 



STEWART, ROBERT and HIRST, C. T. Comparative Value of Irriga- 

 tion and Dry-Farming Wheat for Flour-Production. Journal 

 of Industrial and Engineering Chemistry, Vol. IV, No. 4, April, 

 1912. 



TOLLENS, B. The Ash Constitutents of Plants. Experiment Station 

 Record, Vol. XIII, Nos. 3 and 4. 



WIDTSOE, J. A., and STEWART, ROBERT. The Chemical Composi- 

 tion of Crops as Affected by Different Quantities of Irrigation 

 Water. Utah Experiment Station, BuUetin No. 120 (1912). 



WIDTSOE, J. A., and STEWART, ROBERT. The Effect of Irrigation on 

 the Growth and Composition of Plants at Different Periods of 

 Development. Utah Experiment Station, Bulletin No. 119 

 (1912). 



