486 THE PRINCIPLES OF SOIL MANAGEMENT 



many harvesting implements. The potato-digger, for 

 example, very thoroughly breaks up and cultivates the 



Fig. 145. Corn planter; also compacts the soil over the seed and establishes 

 capillarity with the lower soil, thus bringing more moisture in contact with 

 the seed. 



soil, which process is one important reason for the 

 general high yield of crops following the potato crop. 

 Bean-harvesters and beet-looseners also have a similar 

 action on the soil. 



343. Packers and crushers. These may be divided 

 into two groups: (a) Those implements which aim to 



Fig. 146. Scotch chain harrow. A good pulverizer and very effective on 

 pastures in breaking up and spreading "droppings." 



