CHAPTER III. 

 NATURAL ENVIRONMENT. 



The individual plant is the complex resultant of two 

 forces, heredity and environment. Those characteristics of 

 wheat which are acquired from environmental influences and 

 which are transmissible from generation to generation of 

 plants may be considered as belonging to heredity, a subject 

 fully treated in the preceding chapter. The natural environ- 

 ment, consisting of soil and climate, is a pronounced factor in 

 the growth of wheat, independent of the artificial modifications 

 known as cultivation. The latter subject is treated in a later 

 chapter. 



ENVIRONMENTAL INFLUENCES. 



Soil. There are mechanical and chemical differences in soil 

 that exert a varying influence upon the quantity and quality 

 of wheat. The effect upon yield is more pronounced than that 

 upon quality. In North Dakota 39 different samples of Blue 

 Stem and Scotch Fife wheats of known history were obtained 

 from farms representing the varied soils of the state. Sown 

 upon the same soil, all gave approximately the same results in 

 yield and quality of grain and straw. They also matured at 

 the same date, and had like periods of development. Another 

 experiment was made in which seed raised from one soil was 

 hand picked to uniformity, and then grown upon various types 

 of North Dakota soil in different portions of the state. The 

 resulting grain and straw showed great variation. 1 Similar 

 experiments were made in Indiana 2 and Maryland 8 with prac- 

 tically the same results. 



The soil has been a great factor in determining the distribu- 

 tion of wheat. Much of the wheat of the United States is 

 grown upon glacial drift soil. There are two general types of 

 this soil: The uplands, which are usually of a light-colored, 



1 N. D. Bui. 17, pp. 89-95. 

 1 Ind. Bui. 41. 

 Md. Bui. 14. 



