192 THE OLIVER PLOW BOOK 



objection is unfounded where listing has been practiced 

 on the kind of soil for which it is intended. Baking so 

 that the corn cannot break through has not been observed 

 in the light sandy soils. There have been some very sad 

 experiences with listing on heavy packing soil. 



When the field has been listed and properly tended so 

 that the last cultivation levels the ridges it has prac- 

 tically the same kind of surface as checked corn. There- 

 fore the customary rotation of small grain and corn can 

 be practiced to advantage. The prevalent method of 

 putting in the small grain crop is to disk the field which 

 was previously in corn in the early spring. Where the 

 cultivating has been properly done and the ridges 

 entirely leveled no difficulty is encountered in seeding 

 the spring grain in the cornstalk field. 



To be brief, the advantages of listing are as follows: 



1 . The prevention from blowing of light soils due to the 

 ridges of the field. 



2. The saving of moisture and the use of more sub- 

 soil moisture by putting the roots deeper into the ground. 



3. The saving of labor in the early spring. 



4. Permitting a larger acreage than would otherwise 

 be possible since it supplements planting in ridges where 

 moisture conditions are difficult. 



The middle breaker or "lister" is a combination of a 

 right-hand and a left-hand plow bottom without the 

 landside, the object being to throw the dirt to turn a 

 furrow slice in both directions. This construction per- 

 mits one mouldboard to act as a landside to the other, 

 however, in the uses to which the middle breaker is put 

 there is often greater pressure against one of the mould- 

 boards than the other. This would naturally cause the 

 entire bottom to swerve towards the side of least resist- 

 ance until the pressure against each mouldboard would 

 be equalized. To offset this a steel rudder is placed 

 midway between the two bottoms to penetrate into the 

 ground to keep the bottom operating in a true line of 

 draft when these unequal conditions are encountered. 



