COST AND UTILIZATION OF POWER ON FARMS. 51 
Table 38. — Average cost per day and per acre of using tractors for various operations. 
Operation. 
2-plow tractors. 
Number 
of 
tractors. 
Cost per 
day. 
Cost per 
acre. 
3-plow tractors. 
Number 
of 
tractors. 
Cost per 
day. 
Cost per 
acre. 
Spring plowing 
Fall plowing 
Disking 
Disking in combination 
Harrowing, etc 
Drawing hay loader. . . . 
Drawing grain binder . . 
164 
1211 
95 
L01 
53 
24 
101 
$12. 78 
12.86 
13.35 
12.55 
11.97 
10.02 
11.60 
$2.01 
2.06 
.71 
.70 
.35 
1.14 
.64 
$18. 07 
18.69 
17.13 
16.82 
19.14 
14.18 
16.45 
$2.15 
2.22 
.59 
.76 
.49 
1.05 
.76 
Much of the variation in these average costs, however, is due to the 
fact that the machines were not all used for the same operations. 
For instance, 95 2-plow tractors were used to pull disks alone, and 
the average cost per day for these 95 was $13.35. One hundred and 
one tractors were used for disking in combination with harrows or 
other light implements, and the average cost per day was $12.55. 
This does not mean that for any particular tractor the cost per day 
was less when it was used for pulling both a disk and a harrow than 
when it was used for pulling a disk alone. It simply indicates that 
the daily charges for depreciation, repairs, interest, fuel, and oil for 
the 95 used for pulling disks alone was greater than for the 101 used 
for pulling both disks and harrows. Similarly the high cost of $19.14 
per day shown for harrowing with the 3-plow tractors was due simply 
to the fact that the charges mentioned above were high for the 7 
tractors which were used for this work. When these variations in 
the cost of operating individual tractors are taken into account, there 
is little significance in the differences shown between 2-plow and 
3-plow tractors in the cost of power for the different operations. 
The average cost per day of using the 2-plow tractors for drawbar 
work was $12.67, the 3-plow tractors $17.73, and all tractors $14.51. 
Except for possible differences in the amounts of fuel and oil used, 
the costs per day of using the tractors for belt and custom work 
would be approximately the same as the costs for drawbar work. 
The marked decline in the prices of gasoline, kerosene, and lubri- 
cating oil since the investigation was made has resulted in a con- 
siderable decrease in the cost of operating tractors. At present 
(September, 1921) the average price of gasoline to farmers in the areas 
studied is about 19 cents, kerosene 10 cents, and lubricating oil 40 
cents. The cost of fuel and oil for the tractors as computed on 
these prices is 57 per cent of the cost as based on the 1920 prices. 
Assuming no change in depreciation, interest, and repair costs, the 
present cost per day and per acre of operating the tractors would 
be 82 per cent of the 1920 costs given above. (See Table 42.) 
