14 
BULLETIN 997, U. S. DEPARTMENT OF AGRICULTURE. 
average the men on the smaller farms did a somewhat greater amount 
of custom work with their tractors during the year of the investigation. 
For the entire 286 farms, 76.3 per cent of the work the tractors 
did, as measured in days, was drawbar work on the home farm, 8.8 
per cent was belt work at home, 6.5 per cent was drawbar custom 
work, and 8.4 per cent was belt custom work. 
Table 10. — Days of tractor work on farms of different sizes. 
Size of farm (crop acres). 
Number 
of farms. 
Days of work on 
home farm. 
Days of custom 
work. 
Total 
Draw- 
bar. 
Belt. 
Draw- 
bar. 
Belt. 
days. 
Lessthan80 
7 
28 
71 
56 
47 
36 
19 
22 
11.1 
17.5 
19.1 
22.1 
26.0 
28.5 
31.7 
32.6 
2.0 
2.3 
3.1 
3.0 
2.1 
2.1 
2.0 
3.9 
4.0 
2.3 
2.6 
2.2 
1.3 
1.9 
1.5 
1.0 
5.9 
3.1 
3.7 
2.4 
1.3 
1.6 
0.4 
4.3 
23.0 
80 to 119 
25.2 
120 to 159 
28.5 
160 to 199 
29.7 
200 to 239 
30.7 
240 to 279 
34.1 
280 to 319 
35.6 
320 and over 
41.8 
All 
286 
23.5 
2.7 
2.0 
2.6 
30.8 
Size of Farm 
(Crop Acres) 
Less than 80. 
80-119..... 
120-159 
1 60 - 1 99 
200 - 239 
240-279 
2 80-319...... 
320 and over 
Drawbar Work, /tome Farm. 
Be/t Work, /tome Farm. 
Drawbar Work, Custom 
Bett Work, Custom 
Fig. 3.— Days of work per year done by tractors on farms of different sizes. 
On the farms with less than 80 crop acres the drawbar work on the 
home farm constituted only about 48 per cent of the total; and on 
those with 80 to 119 crop acres it constituted about 69 per cent of 
the total. On the farms with 280 to 319 crop acres, drawbar work 
at home constituted 89 per cent of the total, and on those with 320 
or more crop acres, it constituted about 78 per cent of the total. 
Figure 3 shows graphically the relative importance of the different 
kinds of work on the farms of different srzes, and illustrates the error 
which would be made in assuming that the entire usefulness of a 
tractor is confined to work where it competes directly with horses. 
The number of days of work done by an individual tractor'depended 
upon the particular field operations for which it was used, the amount 
of belt and custom work done, and to a certain extent upon the 
