Undisked stubble plowed. Observe 

 that the ground is turned up in lumps, 

 that there are open spaces at the bottom 

 of the furrow which prevent the close 

 compactness cf the lower portion of 

 the turned furrow with the soil beneath 



Disked stubble plowed. The mulch 

 formed by the disk harrow fills up the 

 open spaces at the bottom of the fur- 

 row, thereby forming a close connec- 

 tion with the sub-surface 



This illustration represents the field 

 above harrowed with a pegtooth harrow. 

 The air spaces are still at the bottom 

 of the furrow 



This illustration represents the field 

 above treated with a pegtooth harrow 

 after plowing. The surface is in com- 

 paratively good condition, and the bottom 

 is compact 



