178 SOILS 



PLANKING 



Closely allied to the roller in its effect upon the 

 soil is the tool variously known as a planker, clod- 

 crusher, smoother and sometimes as a drag;, boat 



O 



float or plank harrow. The terms "drag," * float," 

 and "boat," however, are more properly applied 

 to the tool known as a "stone boat" in the East, 

 which is about 2x5 feet, smooth on the bottom, not 

 corrugated, and which is used, not for mellowing 

 the soil but for hauling stones from the field, plows 

 and harrows to the field and similar work. The 

 planker is usually home-made and therefore is not 

 uniform in construction. A few cultivators have 

 planker or clod-crushing attachments. 



Nearly all home-made plankers are made of two 

 hardwood planks about 2x8 inches and 6 to 8 feet 

 long. Notches about two inches deep and eight 

 inches apart are made in each of these bed pieces 

 and into these are nailed or bolted 2-inch planks 

 about six feet long, each plank overlapping the 

 one next to it, like clapboards. Or several planks 

 may be merely overlapped and bolted together. 

 Some prefer to have a space of several inches be- 

 tween the planks. This is pulled broadside and 

 exerts a powerful pulverising and smoothing in- 

 fluence on the surface, especially if weighted with 

 a driver or stone ballast. 



The planker has very little compacting effect, as 

 compared with the roller, because its much lighter 

 weignt is distributed over many square feet of sur- 

 face; while all the weight of the roller rests upon 

 the narrow line where its curved surface touches 

 the soil. The planker is distinctly a clod-crushing 

 and levelling implement. In this respect it resem- 

 bles the harrows and is very properly called a 



