4 BULLETIN 1000, U. S. DEPARTMENT OE AGEICULTrEE, 
used in this discussion, includes all items of expense except the charge 
for the use of land: namely, the cost of man and horse labor, the 
cost of materials (such as seed, manure, fertilizer, containers, and 
chemicals used in the treatment of seed or for controlling insect 
pests), machinery and equipment costs, taxes, insurance, thrashing 
charges, and overhead. Total cost takes into account the items 
which have been enumerated and includes, in addition, interest, 
or rent charge for the use of land. 
As an aid to estimating total expense of production, it is important 
to know what part the cost of labor and materials is of the total 
operating expense. In each of the following tables this percentage 
has been indicated. In a few cases it was not possible to determine 
the percentage for each district, but in these instances the relation- 
ship for the region has been worked out and these percentages can 
be applied in estimating the total operating expense. For several 
crops the labor and material requirements constitute rather uni- 
formly from 65 to So per cent of the total operating expense. 
In studying the various tables which follow it may be desirable 
to know how each item of cost compares with other items of cost, 
with the total operating expense, or with the total cost. A table 
therefore has been prepared for each crop, showing the percentage 
distribution of 'the total operating expense, and also of the total cost, 
among the various items of cost. In the production of a crop like 
wheat or barley the percentage distribution of the total operating 
expense may not vary greatly in two distinct regions, one of which 
has high land values, the other low land values. TThen total cost 
is considered, however, there will be a wide variation, because in 
the district having high priced land the interest charge will consti- 
tute a comparatively large part of the total cost. 
In connection with each table certain significant differences in the 
quantity requirements shown for the respective districts are pointed 
out. If field practice influences requirements appreciably, especially 
if such practice happens to be somewhat unusual, the practice in 
question is discussed briefly, so that the reader may be able to inter- 
pret results accurately. It is not possible, however, to discuss in 
a bulletin of this character all the methods involved in the production 
of each individual crop. 1 
METHOD OF PRESENTATION. 
The acre requirements for different crops are given in tabular 
form. The distribution of labor for each enterprise is also shown 
graphically in figures 1 to II. The purpose of these graphs is to 
i Several bulletins relating to the cost of producing special crops have been issued by the Office of I arm 
Management and Farm Economics. These publications describe the more important methods of produc* 
tion in some detail. (See reference lists which accompany tables.) 
