118 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



whose habits are the same as those of the crop ; the weeds require 

 fertility and therefore take nourishment which belongs to the 

 plant, thus decreasing the yield of grain or whatever the crop 

 may be. The single crop system tends towards breeding of in- 

 sects which are enemies of the crop. 



T can well remember in Southern Minnesota, 25 to 30 years 

 ago, where the single crop system practiced with wheat gave 

 the cinch bugs an opportunity to develop. In order to get rid of 

 the cinch bugs, farmers quit growing 'wheat and went into live- 

 stock raising. Since this system of farming has been taken up 

 I have heard little or nothing concerning the cinch bug. Fungus 

 diseases develop when a single crop is grown year after year 

 on the same soil. We have the flax sickness and clover sickness ; 

 smut destroys large quantities of the grain crop; the cow pea 

 wilt, bean sick soil, etc., follow the single crop system. Plants 

 also secrete from their roots substances which have a toxic effect 

 upon the plants and for this reason it is necessary to change 

 the crop. 



Dairying offers an opportunity for the rotation of crops and 

 raising of those crops that are of different benefit to the soil. 

 For instance, what would clover and alfalfa hay be worth if it 

 were not for the animals of the farm? It is necessary to grow 

 these crops, for the bacteria which live upon their roots gather 

 nitrogen from the air and deposit it in the soil. The roots 

 themselves supply a large amount of organic matter which is 

 necessary, for in the decomposition of organic matter acids are 

 secreted which liberate the plant food in the soil. 



I might go on and mention other advantages of crop rota- 

 tion, but these which I have given are sufficient to indicate its 

 value to the soil and how dairying encourages and gives oppor- 

 tunity for the rotation of crops. It is plain that the dairy cow 

 plays an important part in our agricultural operations and 

 makes it possible to handle the soil in the best possible way.. 

 She not only returns a large percentage of fertility which the 

 plants have removed from the land, but makes it possible to 

 grow crops which are advantageous to soil improvement. She 



