20 
BULLETIN 1 26, U. S. DEPARTMENT OF AGRICULTURE. 
operator of a farm plans to increase the depth of his plowing, it is 
usually necessary to make provision for more horsepower. With 
the four- and five-horse crews it is altogether probable that the 
plowing was done somewhat deeper than on the group of farms 
using three horses per crew. An average day's work plowing varied 
from 1.7 acres to 2 acres for the different crews. 
DISKING. 
Occasionally some disking is done preparatory to plowing. Again, 
it is sometimes necessary to do the plowing when the soil is very dry. 
Consequently the surface may be left in a lumpy condition. The disk 
harrow can be run to advantage over such fields. This plan not only 
reduces the rough surface, but it also has a tendency to bring the 
Fig. 6. — Disking land after plowing. 
soil back to the proper tilth. The disk stands second to the plow in 
effectiveness. 
The field records show that much more disking was done in the 
Rocky Ford district than in either of the other sections under study. 
This may have been due to a heavier soil and climatic differences. 
(This feature will be discussed more fully under irrigation practice.) 
Disking was done at the same time as plowing, or later. The average 
width of disk used varied from 6.5 to 8.6 feet (fig. 6) . 
The prevailing crew for disking consisted of one man and four 
horses. Forty-three growers in Rocky Ford, 15 at Fort Morgan, and 
15 at Greeley did the disking with a 1-4 crew. There were 15 farms 
at Rocky Ford that utilized a crew of one man and three horses. It 
cost 54 cents more per acre to do the disking at Rocky Ford than at 
