50 
BULLETIN 1348, U. S. DEPARTMENT OF AGRICULTURE 
adapted to the majority of the operations used on nonrow crops, but 
in the case of row and hay crops, this has proven more difficult and 
special equipment has had to be developed m many cases. This cir- 
cumstance has tended to retard the use of the tractor where these 
types of farming prevail, except on the larger farms where it is 
easier to utilize a combination of both tractor and animal power 
economically. Figures 51 to 54 show the proportion and distribu- 
tion of each of these three types of farming in the United States. 
The cost per unit of power developed probabl}^ is the most vari- 
able of the factors affecting' the choice of power in different parts 
of the United States. This is particuarly true of animal power, 
owing to the use of rather bulky feeds which are expensive to trans- 
port and which, as a result, are relatively cheap in those areas where 
an excess is produced and relatively expensive in the areas where it 
is necessary to ship in a part of the amount required. The result is 
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Fig. 54. — Distribution of hay crop. Each dot represents 10,000 acres. Hay crops include wild ana 
prairie hays, alfalfa, clover, timothy, millet and various small grains, and other legumes cut for 
hay. (Based on 1922 Crop Report of U. S. Department of Agriculture) 
a corresponding variation in the cost of the power produced. Fig- 
ure 55 shows the approximate average cost of animal power in sev- 
eral representative States as affected by these differences in costs 
of feed, and the graph partially explains why animal power has 
proved more popular than tractor power in certain of the Central 
Western States during the present period of deflation in farm prices. 
THE FUTURE USE OF POWER ON FARMS 
This bulletin has so far considered only the amount of power util- 
ized by agriculture under present conditions, and it may be of inter- 
est to discuss briefly some of the factors that may affect the use of 
power in this industry in the future. Some of these factors may be 
itemized as follows: An increase or decrease in the total crop acreage 
or in the quantities of the various commodities produced; changes 
