54 
BULLETIN 654 ; U. S. DEPARTMENT OF AGRICULTURE. 
Table XXV. — Relative efficiency in the use of land, worhstock, capital, and labor, on 
irrigated farms of different sizes in southern Arizona. 
A verage 
area. 
Work- 
stock 
per farm. 
Value of 
work 
stock 
per head. 
Man 
units in 
labor in- 
cluding 
operator. 
Value of 
man 
labor per 
acre. 
Hired 
and 
family 
labor per 
acre. 
Area 
farmed 
per man. 
Area 
farmed 
per 
horse. 
Capital 
managed 
per man 
unit in 
labor. 
Produc- 
tive 
animal 
units per 
man. 
Acres-. 
Head. 
Acres. 
Acres. 
11 
1.8 
$86 
1.2 
$58.2 
$11.00 
9.2 
6.2 
$4, 514 
7.1 
20 
2.8 
100 
1.1 
33.7 
7.05 
18.2 
7.1 
6, 550 
10.1 
30 
3.4 
110 
1.2 
26.3 
6.23 
25.0 
8.8 
9, 038 
12.2 
40 
3.8 
117 
1.4 
20.4 
6.45 
28.6 
10.5 
7,942 
13.2 
62 
4.9 
121 
1.7 
20.2 
9.06 
36.5 
12.7 
9,060 
13.1 
80 
5.0 
117 
1.8 
15.3 
. 7.19 
4-1.4 
16.0 
. 9, 213 
16.3 
101 
.5.3 
115 
2.1 
14.7 
8.28 
48.1 
19.1 
9,966 
14.0 
137 
7.8 
132 
2.7 
15.5 
9.01 
50.7 
17.6 
10,019 
20.6 
160 
7.7 
121 
2.9 
14.1 
8.88 
55.2 
20.8 
11,089 
23.3 
244 
10.7 
127 
3.9 
12.3 
7.96 
62.6 
• 22.8 
12, 042 
26.2 
530 
16.3 
127 
6.5 
9,3 
6.99 
81.5 
32.5 
13, 765 
36.4 
The number of acres farmed per man and per horse increases 
steadily as the size of the farm becomes larger. A man unit in labor 
manages nine times as many acres in the largest-farm group as in 
the smallest-farm group, three times as much capital, and five times 
as many productive animal units. One horse works five times as 
many acres in the largest-farm group as in the smallest-farm group. 
The work stock is considerably more valuable on the large farms. 
The number of man units in labor increases with the size of the 
farm, but the total value of hired and family labor per acre, except 
in the two extreme groups, remains nearly constant, indicating that 
the increasing efficiency of man labor with increasing size of farm is 
due chiefly to increased efficiency of the operator himself and his 
equipment. This is also indicated by the steady decrease in the total 
value of man labor per acre as the size of the farm increases. 
The rate of interest earned on capital rises with the size of the farm 
up to 80 acres and then slowly falls, with the exception of the group 
ranging from 81 to 119 acres, where there is a sharp decline followed 
by a rise in the group of next larger farms. In calculating this 
interest rate the contribution of the farm to the family living was 
added to the farm income, and from the sum the value of the oper- 
ator's labor 1 was subtracted; the difference was taken as interest 
earned by capital. Table XXVI shows the relation of size of farm to 
interest earned on capital invested. While farms of 20 and 30 acres 
pay a slightly higher interest rate on investment than farms larger than 
159 acres, they pay but little more than half as much for the farmer's 
labor and managerial ability; and if this item were taken at a uni- 
form figure of $600 for all f arms the farms larger than 40 acres would 
pay a higher interest rate than the small farms up to and including 
40 acres, with the exception of the group averaging 101 acres and the 
1 The value <'i the operator's time was obtained by asking him the question: "How much would it cost 
you to hire a mm tp do the work that you do and manage the farm as well as you manage it." 
