FIFTY-THIRD ANNUAL CONVENTION 27 



the necessary area of pasturage in half. Where it takes an 

 acre and a half of bluegrass, three quarters of an acre of 

 sweet clover will do a much better job of supplying a cow 

 with all the green feed she wants, and cows never produce 

 better than on good pasture. Where thirty cows are kept 

 twenty-two and a half acres of sweet clover will do the 

 job formerly requiring forty-five acres, and will not require 

 supplementary summer feeding of hay and silage as when 

 bluegrass dries up in July and August. 



Under the system outlined above, a legume will be on 

 the land used to support the dairy two out of three years. 

 Instead of robbing posterity, this rotation stores up fertility 

 for its use, since 75% of the nitrogen may be recovered in 

 the manure and returned to the land while a large amount 

 will be left in the roots and refuse in the field, which also 

 supply humus. 



Rotation a Means of Controlling Plant Disease 



A rotation also helps to control plant diseases and in- 

 sects. Corn root rot is an example of such a disease, while 

 the corn root louse is held in check the same way. But 

 what may prove to be the greatest advantage of a good 

 rotation such as has been cited is that it can be used to 

 control the European corn borer which is so rapidly sweep- 

 ing westward across the continent and is already in Illinois. 

 One of the very best controls so far discovered has been to 

 put all the corn grown in the silo, for the ensiling process 

 kills the borer while the borer does not harm the legumes. 

 The dairyman can continue his business about as before, 

 while it looks as if the cash corn growers would be about 

 ruined for a time. 



Rotation Means Better Labor Distribution and More 

 Diversification 



Labor is utilized to better advantage under a good 

 rotation, for the labor requirements on different crops come 

 at different times, thus keeping labor fully employed and 

 reducing the strain of peak loads which occur where the 



