CULTIVATION OF WHEAT 129 



As wheat is a self-fertilized plant and therefore is not easily 

 influenced or changed, we can not expect a stock of wheat to ma- 

 terially improve or degenerate from year to year. This would be 

 especially true if the wheat were all of one fairly pure type. How- 

 ever, if the wheat is a mixture of types, then we should expect those 

 types best adapted to produce the heaviest and best grains. If the 

 difference in weight is sufficient, a rough separation can be made 

 with a fanning mill ; but if the difference in weight is not great, we 

 have no machine sufficiently sensitive to make a separation. 



Size of grain where all are well developed is not important, as 

 large and small grains come from the same head and carry similar 

 hereditary characters. 



We may, therefore, conclude that if the seed wheat is sound and 

 of good weight, there is probably no good reason to expect further im- 

 provement by fanning or grading; but if there is a noticeable por- 

 tion of light seed, it would be desirable to grade. Impurities, as 

 noxious weed seeds, should always be removed. 



Changing Seed. It is a more or less common belief that a 

 variety will run out if grown for a long time in one place. Eather 

 extensive trials were made by the North Dakota and Minnesota 

 stations. Seed of the same varieties was exchanged between these 

 States, in all 23 trials, with the result that in no case was the change 

 an advantage and the average showed a decrease of 2.5 bushels per 

 acre, when the seed from the other station was compared with 

 home-grown. 



Home-grown Seed at Ontario. At the Guelph Station, On- 

 tario, Canada, certain varieties of cereals have been continuously 

 grown for many years, and in all cases there has been no apparent 

 decrease in yield, but, on the other hand, all the varieties appear to 

 yield better now than before. 



Cultivation of Wheat. In Europe in certain regions where 

 labor is cheap and farming intensive, small grain is cultivated by 

 hoeing between the drill-rows. In ordinary practice, however, no 

 culture is given after the grain is sown. 



Going over the fields with a peg-tooth harrow or weeder is prac- 

 tised in some parts of the wheat belt, and is considered good practice 

 in dry years. To use the harrow the plants should be drilled, and 



