Missouri Corn Growers' Association. 



341 



beneficial in that it promotes bacterial growth and in this way 

 helps set free plant food. This, together with the beneficial 

 physical effect that organic matter has upon soils in making 

 them work easier and in increasing their water-holding capacity, 

 emphasizes the importance of maintaining a good supply of 

 organic matter if the soils of the corn belt are to remain produc- 

 tive. Since this is best accomplished through rotation of crops, 

 together with the use of manure and green manuring crops, it is 

 evident that a good cropping system is by far the most important 

 single factor influencing the yield of crops. But the cropping 

 system alone will not maintain the yield where the crops are 

 removed. It is necessary that this be supplemented either with 

 manure or fertilizers or both if the yield is to be maintained. 



Champion ten ears white corn, eleventh annual Missouri State Corn Show. Sliown by 



J. G. Douglass, Shelbina, Mo. 



In another series of plots at the Illinois Station a corn-oats- 

 clover rotation was practiced where all was returned to the land 

 except the grain and clover seed harvested. In one case the 

 corn stover, oat straw and the clover straw were turned under, 

 together with legumes as catch crops. This system was desig- 

 nated as "grain farming," and was compared with a second 

 scheme in which all of the crops were removed but equivalent 

 manure returned and which was called "live stock farming." 

 The effects of these two systems upon the fertility of the soil 

 were compared where no further soil treatment was given and 

 where lime and mineral fertilizers were used as supplements. 

 The following table illustrates the influence of the two systems 

 upon the yield of the corn crop: 



