SOIL MOISTURE 



337 



Undisked stubble plowed. Ob- 

 serve that the ground is 

 turned up in lumps; that 

 there are open spaces at the 

 bottom of the furrow which 

 prevent the close compact- 

 ness of 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 

 furrow, thereby forming a 

 close connection with the sub- 

 surface. 



This illustration represents the 

 field above treated with a 

 pegtooth harrow after plow- 

 ing. The surface is in com- 

 paratively good condition, but 

 the bottom is not compact. 



This illustration represents the 

 field above harrowed with a 

 pegtooth harrow. The air 

 spaces are still at the bottom 

 of the furrow. 



