THE PRINCIPLES OF TILLAGE 



SOIL FIRMERS. 



117 



Among the implements that firm the soil and thus 

 crush lumps or lessen the air spaces, or pack the soil 

 about the seed, are the home-made planker or scrubber 

 and the press attachment for drills. All of these are 

 soil firmers or clod crushers of different degrees of ef- 

 ficiency and of vastly different cost. One may fit certain 

 specific soil conditions better than another. Each has a 

 place in the economy of some particular farm and most 



Fig. 42. Types of Soil Firmers. 



(a) Surface packer or pulverizer; (b) Subsurface packer; (c) Culti- 

 packer; (d) Smooth roller; (e) Float and planker. 



of them when used intelligently will prove a profitable 

 investment. Yet no one is absolutely essential on any 

 farm. The work of firming the soil can be accomplished 



