AN APPRAISAL OF POWER USED ON FARMS 7 
gines were employed for operating threshing machines and other 
heavy belt work soon after the Civil War; and the gas engine came 
into successful use about the beginning of the twentieth century. 
From that time there has been a continuous and rapid development 
in the use of mechanical power in agriculture. Tractors were first 
used for draft work when a demand developed for large power units 
for grain farming in the West. Steam tractors were first used for 
this purpose but soon were displaced by the more practical gas 
tractors. 
The small gas tractor, the truck, the automobile,^ and the use of 
electric power have been of more recent development and have only 
become important factors in agriculture during the last 10 or 12 
years. Figure 5 shows the approximate amount of each kind of 
power available on farms from 1850 to 1924. 
ANNUAL USE AND COST OF POWER ON FARMS IN THE UNITED 
STATES 
The tables on page 8 summarize the power available on farms in 
the United States, and give an estimate of the amount and cost of 
the power developed annually, together with the principal opera- 
tions through which it was utilized under 1924 conditions. 
Approximately 16,000,000,000 horsepower-hours are utilized an- 
nually at the present time. Of tliis amount animal power furnishes 
about 61 per cent, tractors 16 per cent, motor trucks slightly less 
than 4 per cent, stationary engines 12 J^ per cent, windmills slightly 
over 1 per cent, and electric power 53^ per cent. 
Of the power developed, about 48 per cent is utilized for field 
work, 15 per cent for road hauling, 7 per cent for hauling about the 
farm,^ 17 per cent for heavy stationary work, and 13 per cent for 
light stationary work. (Heavy stationary work is considered as all 
operations requiring more than 5 horsepower.) 
Plowing and listing, grouped together, rank highest of all farm 
operations in the amount of power utilized, with a total of approxi- 
mately 22 per cent of the draft work or almost 16 per cent of the 
total power used; road hauling ranks only slightly lower; threshing 
stands highest in the stationary operations, requiring over 25 per 
cent of aU the stationary power utilized; and pumping for irriga- 
tion and drainage rank next, using over 20 per cent of this type of 
power. 
* The automobile as a source of power on farms has not been considered in this bulletin, as only a small 
part of the power developed by this means is used to do actual farm work. Surveys that have been made 
would, indicate that at least 80 per cent of the use the farmer makes of the automobile is in the care and 
supervision of his business. 
6 See Tables XXII and XXIII for tonnage of farm and road hauling and the average length of haul. 
