90 CORN 



*"Where corn is followed by oats in a two-year rotation, the de- 

 struction of the humus is less rapid and the multiplying of corn insects 

 is discouraged by the change to oats every other year. During the 

 first II years the yield decreased from more than 70 bushels to 62 

 bushels, and during the next 16 years a further reduction of 16 bush- 

 els has occurred." 



It is to be noticed that in computing the average yield for the corn- 

 oats-clover rotation, the yield for the very dry year of 1901 was con- 

 sidered, and yet this method proved the most profitable. 



At this same Station, the sowing of legume catch crops between 

 the rows of corn in the "corn-oats-elover" rotation at the time of the 

 last cultivation, raised the yield from 66 to 69 bushels. This was done 

 in the so-called "Grain Farming" experiment.* 



Considering the last six crops in an experiment which has been 

 conducted in Illinois for twenty-nine years, and comparing three 

 cropping systems, continuous corn ; corn and oats ; and corn, oats and 

 clover, the value of a rotation including a legume is well marked. The 

 total value of six continuous corn crops was $58.08. The total value of 

 the last six crops in the corn and oats rotation (three crops of corn 

 and three crops of oats) was $79.01, and the total value of the last six 

 crops of the corn, oats, clover rotation (two crops corn, two crops 

 oats, two crops clover) was $92.09. 



Rotation compared wdth continuous corn shows a difference in 

 favor of the rotation of approximately $34.00 per acre for the last six 

 crops. 



The average value of each of the six corn crops under continuous 

 cropping with corn was $9.68 as compared with an average value of 

 $27.16 for the two corn crops included in the last six years of the crop 

 rotation plots, or an average value of $15.35 for all crops from the 

 rotation plots. 



Corn alone is not a balanced ration. With an abundance of carbo- 

 hydrates and fat-producing compounds additional protein is needed' 

 in feeding for the most economic gains. This can be produced on the 

 farm in the form of leguminous crops, more cheaply than it can be 

 purchased in the commercial concentrates, hence, crop rotation. 



MANURES. In the maintenance of the fertility of corn belt land, 

 farm manures form a very important supplement to crop rotation. 

 Manures serve the following purposes in the soil : 



(1) Increase plant food content of soil. 



(2) Aid in making plant food already in soil more readily 

 available. 



(3) Improve physical condition of soil. 



♦Illinois Bulletin No. 125 



