TILLAGE 327 



IMPLEMENTS OF TILLAGE 



Tillage implements are divided into five classes plows, har- 

 rows, compacters, seeders, and cultivators. 



1. Plows. The. mold-hoard plow is one of the most common 

 as well as one of the hest implements for loosening the soil and 



A B c 



FlO. 137. Diagram showing the theoretical action of the plow. The sliding or shearing it; 

 accompanied by more or less of a rolling action, all of which pulverizes the soil. (King.) 



turning under vegetable material.. It brings about almost a com- 

 plete inversion of the furrow-slice, and in doing this pulverizes the 

 soil. The mold-board is of such a curvature that when the soil 

 passes over it, it produces a shearing force in the soil as if made up 

 of different layers somewhat similar to the effect of bending several 

 leaves of a book and brings about pulverization (Fig. 137) if the 



A n c 



Fio. 138. Showing the three types of mold-hoards. A-Sod. B-General purpose. 



C-Stubblc. 



soil is in good condition for plowing. If too dry so that the soil 

 is cloddy little pulverization is accomplished. If the soil is too wet 

 for plowing this shearing breaks down the granules, producing par- 

 tial puddling, very injurious to the soil. The plow should be set 

 so that the furrow-slice will be cut free from the soil beneath and 

 practically all inverted. Mold-board plows are divided into stubble, 

 general purpose, and sod plows. 



