414 IOWA DEPARTMENT OF AGRICULTURE 



It has been held by many that since dairying offers an opportunity for 

 the rotation of crops, very little attention, if any, need be given the soil to 

 keep up its fertility. No one questions that the rotation of crops is not 

 beneficial to the soil; that it is one of the necessary things in a successful 

 system of agriculture, but to state that rotation tends to increase the 

 fertility is misleading in the extreme, for the increased crop yields that 

 come by rotation should indicate that more fertility is being removed. 

 We cannot make something from nothing. The rotation of crops puts the 

 soil in better physical condition, it gives opportunity to grow crops which 

 tend to liberate the fertility of the soil. The single crop system encour- 

 ages the growth of weeds 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 the breeding of insects 

 which are enemies of the crop. 



I can well remember in southern Minnesota 25 to 30 years ago where 

 the single crop system practiced with wheat gave the cinch bugs an op- 

 portunity 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 si'ckness and clover sick- 

 ness; smut destroys large quantities of the grain crop; the cowpea 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 

 those crops that are of direct 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 se- 

 creted which liberate the plant food in the soil. 



I might go on and mention other advantages of crop rotation, but these 

 whi'ch I have given are sufficient to indicate its value to the soil and how 

 dairying encourages and gives opportunity 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 also gives a market for a 

 large amount of roughage which would be of little value without her. 



It is a noticeable fact that Iowa permits thousands of acres of corn 

 stalks to go to waste, which would furnish thousands of tons of good 

 silage for the dairy cow and for the steer also. 



I wish to say in conclusion that I am pleased to be here. I trust that 

 this magnificent show of dairy cattle is only the beginning of something 



