158 GRASSES OF IOWA. 



temperature and moderate rainfall, but we find it grown to the 

 greatest advantage in that part of India where, at least during 

 the winter months, the climatic conditions of the summer of 

 Europe are most nearly approached. Definite limitation of 

 area cannot be made since the region is not itself sharply 

 defined. 



A study of the tables prepared by Professor Brewer shows 

 that the greatest production of wheat occurs where the mean 

 anaual temperature is 50*^ and 55^^ F. The ideal climate for 

 wheat is one of mild winters, ard some of the most noted wheat 

 regions of the world are where snow and frozen ground are 

 unknown or very rare although most of the wheat of the world 

 grows in regions of cold winters. Rainfall, also, has a marked 

 influence on the amount of wheat production. Twenty-eight 

 per cent of the crop of the United States grows with an annual 

 rainfall of be^wpen 40 and 45 inches, 62.7 per cent where it is 

 between 35 and 50 inches and 92.4 per cent where the annual 

 rainfall is above i5 inches, although there are some exceptions, 

 as in Calif jrnia where the mean annual rainfall is less than 25 

 inches. 



Wheat ripens successfully at the following altitudes: Nor- 

 way, 300 m ; on the southern exposure of the Alps, 1,264 m. , and 

 Thibet, 4,549 m. 



The qual ty of the grain produced in any locality is dependent 

 upon several c )nditions; namely, climate, soil and cultivation. 

 It is said by Frank T. Shutt that certain Russian wheats, like 

 Ladoga* cultivated in the northwest territory has been greatly 

 improvei since its growth in the Canadian provinces. There 

 is a well-marked increase in the amount of albuminoids. The 

 main differ nee between the hard and soft wheat is that the 

 hard wheats contain a greater amount of albuminoids while the 

 soft wheats contain a greater amount of starch. 



Koernicke and Wernerf state that the colder regions of the 

 temperate zone are more favorable for the soft wheats. These 

 are especially characterized by the low contents of albuminoids. 

 These varieties where grown in dry and warmer countries are 

 characterized by an increase in albuminoids. Only certain 

 portions of Iowa are adapted to the growing of spring wheat. 

 The averaee number of bushels per acre in northern Iowa is 

 seventeen; in the south half of the state Mr. Spring estimates 



•Saunders Bull. Canada Cent. Exp. Farm 18: 1893. 

 tHandbucb2: 483. 



