TILLAGE 337 



The bar roller is another form, made up of a series of bars 

 running lengthwise of the roller. 'Phis implement is better than 

 the ordinary drum roller, but is not as effective as the corrugated 

 roller or culti-packer. 



Flankers made by bolting together two or three two-inch 

 boards so that they lap about half may be used to good advantage 

 for crushing clods and levelling without compacting to any extent. 



The Campbell subsurface packer (Fig. 107, page 247) is 

 used in arid and semi-arid regions. Its special advantage is that 

 it compacts deep, freshly plowed soil, leaving a mulch on the sur- 

 face. It consists of a number of wheels with a wedge-shaped edge. 

 These are about five inches apart and revolve independently of each 

 other. As this wheel presses in, the soil is pushed to both sides. 



Fin. 154. Press drill 



thus closing the air spaces, leaving a loose mulch on the surface. 

 This may be used in sandy soils in humid regions to very good 

 advantage. 



4. Seeders (Figs. 153, 154, 155). The tillage done by seeders 

 is purely incidental, yet in many cases very essential. Drills almost 

 invariably till the soil to a considerable extent in opening a furrow 

 every six to eight inches in which to deposit the seed. Where press 

 drills are used the soil is compacted upon the seed. In the planting 

 of corn with the ordinary planter the tillage is similar to that of the 

 press drill, hut not so extensive. Many broadcast seeders, bow- 

 ever, accomplish no cultivation. 



5. Cultivators. Cultivators are for use in intertilled crops. 

 Some stir the soil to a depth of one inch or less, while others work 



