18 BULLETIN 757, U. S. DEPARTMENT OF AGRICULTURE. 
size of farms in North Dakota. None but large farms can utilize 
these labor-saving implements efficiently. 
Fic. 8—The gang plow drawn by the five good horses turns from 5 to 6 acres in a day. 
The gang plow (fig. 8) cuts two furrows of 12 to 14 inches each; 
the most common gang is the 28-inch. The majority of farmers use 
five horses on the gang plow, although a large number use only four. 
5 
Fic. 9.—The spike-tooth harrow covers from 40 to 60 acres per day, depenaive apes 
the width of the harrow and size of the team. 
A very few use six horses on this implement. Usually three horses 
are placed abreast and two in the lead, but when four horses are used 
they are generally driven abreast. 
