84 SOILS AND FERTILIZERS 



surface packer, which accomplishes all that the roller 

 accomplishes in packing the soil without destroying the 

 crumbly condition of the surface. (See Figure 35.) 



The Harrow. - - The harrow should follow the plow 

 as soon as possible. It is better to harrow land after 

 plowing before the surface has dried. When the soil 



FIG. 27. Acme Harrow. 



is freshly turned over, the harrow can pulverize it 

 more easily and prevent the formation of large clods. 

 Some attach the harrow behind the sulky or driving 

 gang plow and perform both operations at once. The 

 harrow should be used after a heavy packing rain, even 

 though the seed bed may have been thoroughly pre- 

 pared. A rain storm packs and settles the tilled soil, 

 which on drying forms a crust that must be broken up 

 to form a soil mulch and prevent the evaporation of soil 

 moisture. 



The spike-toothed harrow is the most common form 

 of harrow, and some farmers have no other kind. It is 

 used for fining the surface, breaking up clods, and level- 

 ing the surface. 



The spikes may be driven through a wooden frame, 



