Tillage to Modify Soil Test tire. 



235 



is relatively large. To put a piece of fall plowing in the 

 best shape the harrow should be lapped half and in doing 

 this the furrow between the two sets of discs will be en- 

 tirely filled and the surface left level. 



FIG. 72. Spring-tooth harrow. 



Where small grains are to follow corn or potatoes the use 

 of this tool will often make the plow unnecessary. 



On the upland prairie soils and others naturally mellow, 

 ground for corn may be plowed in the fall and fitted in the 

 spring with the disc harrow with good results. 



288. The Spring Tooth Harrow. On new land in wooded 

 countries and where the fields are rough and stony the har- 



FlG. 73. Spike-tooth or smoothing h;irro\v. 



