TRACTORS AND HORSES IN THE WINTER WHEAT BELT. aa 
was obtained by multiplying the cost per hour by the number of 
hours required per acre. No charge was made for shelter, taxes, or 
insurance, but these items would amount to only a small percentage 
of the total cost. 
TABLE 36.—Average annual charges for depreciation, interest, repairs, and upkeep of 
tractors of different sizes, 1921. 
Annual charge per tractor for— 
Size of tractor. Number. | 7 | Renal E Farm 
7epre- | Interest. eee xpert labor for | Total. 
| ciation. parts. labor. repairs. | 
LLNS Sa oe 88 $170 $43 $36 $12 36 $267 
27h ee 207 242 68 50 10 8 | 378 
LATIN SS Oe ST re ee eee 40 311 88 87 13 4 508 
Over RDOWae fe ose toe woe 19 371 112 80 Zs 8 | 576 
oi. soe 354 | 239 | 66 | 53 11 ida 376 
First cost—The machines used by 36 of the tractor owners had 
been purchased second hand, and the reports on these machines are 
not included in most of the following tables and discussions con- 
cerning the various items of cost. The average first cost of the two- 
plow tractors which had been purchased new was $948, of the three- 
plow tractors $1,482, of the four-plow tractors $2,023, of the five- 
plow and larger tractors $2,505, and of all tractors $1,473. Most of 
these tractors had been purchased at prices considerably higher than 
now prevail (1924). (See p. 37.) 
Infe-—The average estimated hfe of the 318 machines was 6.8 
years. An owner’s estimate of the life of his machine depended not 
only on its condition at the time and the work which he expected to 
do with it in the future, but also, to a considerable extent, on his 
opinion as to when it would be more profitable to discard it than to 
spend more time and money for repairs. Consequently there were 
wide variations in these estimates. 
Table 37 shows the average estimated life for machines of different 
sizes and ages. Evidently there was no tendency for the men who 
had owned their machines for a short time to overestimate the 
length of time they would last, since for all except the large sizes the 
averages for the machines which had been in use 14 months or less 
were lower than the averages for all machines. 
TaBLE 37.—Estimated life of tractors of different ages. 
| 
2-plow tractors. 3-plow tractors. 4-plow tractors. 5-plow and larger. 
Age of tractors sa | 
(months). Average Average | Average Average 
Number. estimated |Number. jestimated}] Number. estimated) Number. |estimated 
life. | life. | life. life. 
| 
Years. | Years. | Years. 
Years. 
Mean less 5... 5... 33 5.3 76 | 6.6 13 5.6 8 7.5 
LTD Sa eee 26 6.3 63 rosy 1l <0) 2 6.0 
= pte a ee 16 7.9 32 6.7 9 8.0 3 4.7 
ao and OVEr. ==--.-2-- 4 8.0 18 764 3 9.7 1 10.9 
