FARM ORGANIZATION IN SOUTHERN ARIZONA. 
27 
Success in dairy farming is greatly influenced by the productivity 
of the farms and by the quality of the live stock carried. The 
productivity may be measured in terms of productive animal units * 
carried per 100 acres of land, making due allowance for the amount 
of feed purchased . 
The following tabulation of dairy farms will show the steads 
increase in receipts, farm income, and labor income, with the increas- 
ing number of productive-animal units carried per 100 acres of land: 
Table XI. — Effect of increased productivity of land on success in dairy farming in the 
irrigated valleys of southern Arizona, measured in terms of productive-animal units car- 
ried per 100 acres of land. 
Productive-animal 
units per 100 acres. 
Average 
number 
produc- 
tive 
animal 
units 
per 100 
acres. 
Number 
of farms. 
Average 
area. 
Number 
failing to 
make 8 
per cent. 
Value of 
feed pur- 
chased. 
Average 
Total 
receipts. 
Average 
farm 
income. 
Average 
laoor 
income. 
30 and under 
26.1 
48.0 
72.4 
128.7 
11 
67 
72 
39 
Acres. 
108 
87 
79 
57 
5 
17 
5 
3 
$61 
62 
101 
188 
U, 004 
3,409 
3,900 
4,057 
$2, 629 
2,277 
2,678 
2,578 
S795 
30.1 to 60. 
773 
60.1 to 90 
1,201 
1,180 
Over 90 
The average contribution of animals to the receipts on all of these 
farms was 86.3 per cent of the total, while crops contributed an aver- 
age of only 12.1 per cent. It may fairly be assumed, then, that the 
increased income was due to larger numbers of animals. While more 
feed is purchased on the farms carrying the largest number of animal 
units per 100 acres, the amount purchased is not large on any of the 
farms; and it may safely be assumed that the increased number of 
animal units is due to increased productivity of the alf alf a fields ; also, 
that this increased productivity has resulted in greater total receipts 
as well as a larger farm income and labor income. The average num- 
ber of dairy animal units per 100 acres carried on these four classes 
of farms was 19, 35, 53, and 91, respectively. 
Dairy cows are fed practically the entire year on green forage 
consisting chiefly of alfalfa pasture (see fig. 7) . Increasing produc- 
tivity resolves itself, therefore, into the problem of increasing the car- 
rying capacity of the alfalfa fields. It has been found that steady 
pasturing of a single field throughout the year greatly reduces its 
carrying capacity. The plants are eaten so close to the ground that 
they fail to produce the shade necessary to prevent the rapid growth 
of water grasses, bermuda grass, and noxious weeds that soon crowd 
1 An animal unit is the equivalent of a full-grown horse, steer, or cow. Equivalents in other animals 
are determined by food requirements, and in this bulletin 2 calves, heifers, or colts, 7 sheep, 5 hogs, 10 pigs, 
100 chickens, or 50 turkeys are, respectively, regarded as representing food requirements equivalent to those 
ota full-grown horse, steer, or cow, and are therefore counted as one animal unit. Productive animals are 
those that contribute directly to the farm receipts. Work horses are not considered among productive 
animals, because they do not contribute directly to farm receipts. All other animals are considered 
productive. 
