CROPPING SYSTEMS WASHINGTON, OREGON, IDAHO. 3 
which had an average of 46.5 per cent of their rotation area in 
summer fallow lacked $200 per farm of making 8 per cent on invest- 
ment. Those farms with only 6.4 per cent of the rotation area in 
summer fallow made an average of 8.3 per cent interest on capital 
invested as compared with 5.9 per cent on farms having 46.5 per cent 
of the rotation area in summer fallow. It is evident from the crop 
yields of the different farm groups (see "Crop index," Table I) that the 
variation in profits in this case is not due to crop yield. The same 
246 farms are grouped, however, on a basis of crop yields in Table II 
and the influence of this factor on farm profits brought out. 
Table I. — Percentage of rotation area in summer fallow in relation to profits on 246 
farms in eastern Washington, eastern Oregon, and northern Idaho. 
Percentage of rotation area in summer fallow. 
Average 
percentage 
rotation 
area in 
fallow. 
Number 
of farms. 
Labor 
income. « 
Interest 
on invest- 
ment. 
65 
S490 
8.3 
62 
302 
7.5 
70 
- 20 
6.3 
49 
-200 
5.9 
Crop 
index.6 
Under 20 per cent . 
20 to 30 per cent . . 
30 to 40 per cent . . 
Over 40 per cent , . 
6.4 
25.6 
34.8 
46.5 
Per cent. 
98.2 
101.0 
102.4 
96.8 
a Labor income.— What the farmer has left after all expenses have been charged, including interest on 
the money he has tied up in his farm business. 
b Crop index. — Crop yields as compared with the average of all farms, which is taken as 100 per cent. 
Table II. — Crop yields in relation to profits on 246 farms in eastern Washington, eastern 
Oregon, and northern Idaho. 
Farm group. 
Numbec 
of farms. 
Average 
crop 
index. 
Labor 
income. 
Percentage 
made on 
investment. 
Percentage 
rotation 
area in 
summer 
fallow. 
CROP INDEX. 
Under 90 
65 
62 
54 
65 
94 
104 
122 
-$220 
105 
297 
480 
5.5 
6.6 
7.5 
8.2 
28.7 
90 to 99 
29.6 
100 to 110 
32 1 
Over 110 
30.6 
It will be observed from Table II that the farns with an average 
crop yield of but 79 per cent of the average of all farms lacked $220 
of returning an interest of 8 per cent on tne investment (minus $220 
in " Labor income" column). As the per-acre yield of crops increases 
in the succeeding farm groups, the profits also increase until those 
farms having an average crop index of 122 made a labor income of 
$480 after deducting 8 per cent interest on capital invested, Tne 
interest made on capital for the farm group having the smallest crop 
index was 5.5 per cent compared with 8.2 per cent for the farm 
group having the highest yields per acre. The farms with an average 
crop index of 122 made a 27 per cent larger return on capital invested 
than did the farms with an average crop index of only 79. The table 
