SPRING TOOTH AND ACME HARROWS 



153 



Commonly, the disk harrow is all that is required to prepare 

 a good seed bed for small grains on potato and corn land. For 

 weeding and summer fallowing^ these machines are indispensable. 



Sometimes it is desirable to use the disk harrow on land before 

 it is plowed; to break up the surface crust or lumps, to cut up 

 and work trash into the seed bed, and to conserve moisture. 

 When disking is done for the first two reasons, the furrow slice 

 comes into more intimate contact with the subsoil. 



When the seed bed has been made sufficiently mellow or loose 

 through disking, the smoothing or drag harrows are used to give 

 the finishing touches. 



FiQ. 93. — Acme harrow. 



Spring-Tooth and Acme Harrows (Figs. 93 and 94). — The 

 spring-tooth harrow is a most efficient tool on rough and stony 

 ground, and on new land in wooded sections. It may also be used 

 instead of the disk harrow, for pulverizing sandy and gravelly soils; 

 and it may be used effectively in alfalfa fields to loosen the soil and 

 eradicate weeds and grass. It is a more effective tool than the spike- 

 tooth harrow. ■ • . • , -' ^^ 



The Acme or blade harrow is used to a considerable extent in 

 some sections for pulverizing, compacting and for killing weeds. 

 This machine gives best results on loamy soils free from stones. 



^ Summer fallowing is the tilling of uncropped land during the summer. 

 This may be done with the plow or harrow. The common objects of summer 

 fallowing are : to kill obnoxious weeds, to store rainfall of one yea,r for the 

 next, and to conserve moisture. 



