XXII 

 DRAFT OF OTHER IMPLEMENTS 



MEAGRE as are the comparative draft data on 

 plows, they are ample as compared with those on 

 implements of other kinds. Practically no draft 

 tests have been made of modern tillage imple- 

 ments; hence, the draft can be approximated only by com- 

 paring the number of horses used on implements of different 

 sizes. Outside of the plow the ordinary drag harrow, the 

 disk harrow, and the clod crusher or pulverizer are the 

 principal tillage implements used in the North. The 

 following table gives a sort of comparison of these three on the 

 basis of the horses used to pull them, allowing 150 pounds as 

 the effective pull of each horse: 



DISK HARROW DRAG HARROW CRUSHER 



Width, feet 8 20 10 



Weight, total 580 320 1100 



per foot 70 16 138 



Horses required 444 



Approx. draft 600 600 600 



Draft per foot 75 30 60 



The above comparison cannot be regarded as more than 

 a rough approximation. Four horses are often needed to pull 

 a seven-foot disk harrow with 16-inch disks, while the 

 eight-foot harrow, with 16-inch disks, is also equipped 

 with four-horse hitch. The more mellow the soil the greater 

 the penetration; hence, the greater the amount of dirt moved. 

 Sharpness of the disks is a factor in penetration, and a decrease 

 in angle to the line of draft also increases the work done. Con- 



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