TRACTORS AND HORSES IN THE WINTER WHEAT BELT. 35 
The amount of fuel and oil used per acre for the different operations 
by machines of different sizes is shown in Table 40. Although the 
larger machines required greater amounts of fuel and oil per hour, 
there should be no great difference in the amounts required per 
acre for the different sizes if implements which provide full loads are 
used. The table shows that there was little difference in the average 
number of gallons of fuel and oil used per acre for plowing with the 
different sizes. On nearly all of the other operations, however, the 
small machines used the least fuel and oil per acre. In alarge measure 
this was due to the fact that the implements used with the larger 
tractors did not always provide full loads for them. 
TaBLE 40.—Fuel and oil requirements per acre for different operations. 
aT 
} 
| 2-plow. | 3-plow. 4-plow. plow | All. 
Operation. (eee cane 2 ek eee! 
| Fuel.| Oil. | Fuel. Oil. | Fuel.| Oil. | Fuel.| Oil. | Fuel.| Oil. 
Gals.| Gals.| Gals. Gals.| Gals.| Gals.| Gals. | Gals. | Gals.) Gals. 
SCRE ee 2.15 | 0.21 | 2.10 0.15 | 2.20} 0.20] () Cariezos 0.18 
oo Sins oe ee eee 2. 28 ZA he Os ee te FZ. OF -15 | 2.03:| 0. 16.| 2.16 .16 
Se eee Ona a 00 de 32 208 1. C) (2.8) lel Ise fete 1. 24 . 08 
2 PTR me St ee eee f fl Be SW a es . O8 (*) CE eee = 1.18 0g 
Disking plowed ground. ............---- . 96 06/| .99} .06/] @) () (@) (@) 98 06 
Disking unplowed ground............-.- . 80 09; 1.04! .07| .97 () @) | 1.01 08 
JA inic. oe ae 46 04; .49; .03] @) Ca ee eee) ae oe .4 03 
ie 2. Se ee ee ee Ey il 06 7 .05 77 04 . 69 05 ahh 05 
“OL fiird 2 ee . 80 . 06 .81 . 06 ate L06;t @)-f:@) 81 06 
CVn ir. 2 ee eee @) | (@) -89} .06) (Q) (1) (4) ) . 89 06 
Sie ere ee eee gE A at BS 2:3 -09; (@) Cie eee 1.25 09 
1 Less than 10 tractors. 
COST PER YEAR AND PER HOUR OF USING TRACTORS FOR DRAWBAR WORE. 
Table 41 shows the average cost per year and per hour of using 
tractors of different sizes for drawbar work on the home farm in 
each area. For the entire 354 machines the average cost per year 
was $484, or $1.60 per hour. The average cost per year varied in 
the different areas in accordance with the amount of work done per 
year, and since in general the cost per hour was least for the machines 
which did the most work (Table 42) the average cost per hour was 
greatest in the northern area. 
The costs per hour on different farms using tractors of the same 
size showed wide variations because of differences in annual deprecia- 
tion and repair charges, amount of work done during the year, and 
the amounts of fuel and oil used. 
EFFECT OF HOURS OF USE PER YEAR ON COST OF USING TRACTORS. 
Table 42 shows the cost per hour of using two-plow, three-piow, and 
four-plow tractors, that were used for different amounts of work per 
year. The annual depreciation, repair, and interest charges did not 
increase in proportion to the amount of work done with the tractors, 
and consequently the cost per hour was least for the machines which 
did the greatest amount of work. 
These differences are reflected directly in the cost per acre or per 
bushel of producing crops and show how the man whose farm is so 
organized and managed that he obtains large use from his equipment 
