DRAFT OF OTHER IMPLEMENTS 217 



sequently, an eight-foot harrow with disks at right angle to 

 the tongue can be easily pulled over a hard road by one 

 horse, while at the Iowa State College they have a photograph 

 showing eight of their horses eight tons of horseflesh 

 having plenty of exercise in moving two-disk harrows in a 

 mellow cornfield. The condition and texture of the soil play 

 as great a part in the draft as in the case of plows. 



In stiff clay land a two-horse team, weighing 2200 pounds, 

 can be used on a steel spike-tooth lever harrow, cutting fifteen 

 feet. However, the teeth must slant well backward, the 

 driver must walk, and it will take a good many trips over the 

 field to get it into condition. To accomplish much in the way 

 of pulverization the teeth should be set nearly straight and at 

 least one horse provided for each five-foot section. 



Crushers and pulverizers vary considerably in weight per 

 foot of width. One authority says that rollers should not 

 weigh more than 100 Ibs. to the foot and should be at 

 least 24 inches in diameter. Of course the greater the 

 diameter the lighter the draft, unless the weight is increased 

 to correspond, but at the same time the pressure per square 

 inch on the ground is decreased. Ordinarily these implements 

 average about 18 inches in diameter and weigh from 130 to 

 150 Ibs. per foot. An internal-combustion tractor, which 

 had been pulling six 14-inch breaker bottoms in North Dakota, 

 was able to handle three 12-foot disk drills and three 12-foot sod 

 crushers, weighing 1800 Ibs. each. Allowing 60 Ibs. to a foot 

 in width for each, the total draft would be 4320 Ibs. At the 

 Winnipeg motor contest the same year the breaking plows 

 averaged over 700 Ibs. to the plow; hence the draft for six 

 bottoms would check up very well with the amount just as- 

 sumed for the drills and crushers. 



The disk drill, and particularly the single-disk drill, is now 

 practically standard. As a rule the furrow openers are spaced 

 8 inches apart. Three horses will usually handle a 12-foot 

 disk drill, seeding a strip 8 feet wide. Allowing 150-lb. pull 



