126 THE BOOK OF CORN 



corn plants for moisture, light and plant food. Owing 

 to the struggle for existence constantly going- on 

 among the members of the weed families, they are usu- 

 ally particularly fitted to secure their food and to drive 

 out other plants. So that when the weeds grow among 

 the com plants they usually have the advantage in the 

 ability to live. 



In order to get rid of these noxious weeds a large 

 number of kinds of cultivators have been put on the 

 market. In the past the large shovel cultivator, calcu- 

 lated to stir the soil deeply and get rid of all weeds, 

 was the universal cultivator. To-day these implements 

 are not in general use, because it was found they 

 did infinite damage to the corn crop through root injury. 

 In their place has come the small shovel cultivator. 

 Instead of two large shovels there are three or four 

 small shovels attached to each beam. These stir the 

 soil and cut out the weeds, yet do not go deep enough 

 to injure the roots. Along with this kind of machine 

 have come many other types adapted to different 

 conditions of soil and climate. 



Culture Implements — These are divided in general 

 into three classes: i, the harrow; 2, the disk; 3, the 

 knife cultivator. An example of the harrow type is 

 the common weeder. The principle involved here is 

 teeth which scratch out the small weeds, but do not go 

 deep enough to injure the corn roots. In loose, sandy 

 soils this implement is very successful. Large areas can 

 be covered in a short time so that the field can be fre- 

 quently cultivated. However, it will not remove large 

 weeds or stir the heaviest clay soils. 



The second type, or disk, cuts the weeds out with 

 a sharp rolling disk, but does not go deep enough to 

 injure the corn roots. Again, this implement is most 

 successful on the sandy, looser soils, where it can 

 easily move the surface layer of the soil. The first disk 



