MACHINERY COST OF FARM OPERATIONS. 7 
the work in days was found by dividing the service in acres by the 
normal acreage or day's work done by the implements of the 
respective average sizes. This normal day's work, or daily duty of 
the respective machines, was also obtained from the same farmers 
in western New York. 
Following each table, the replacement cost and interest charge 
to correspond have been computed, using 6 per cent as the local 
interest rate. The interest charge for any other rate may readily 
be found by applying proportion to the averages here given. 
THE COST OF REPAIRS. 
Where ordinary care is used by the operator, the repair charges for 
most kinds of farm machinery used in growing crops should make 
up but a small proportion of the total cost of production. It is 
often desirable, however, to know what the average repair charge 
for the different machines may be in order to arrive at a fair allow- 
ance for such repairs in planning future farm work or in determining 
the cost of work already done. But little data have ever been made 
available that could be used by the man on the farm, the county 
agent, the agricultural instructor, or the investigator in farm organi- 
zation and management, in determining the repair cost for the 
machinery used on any given farm enterprise. 
In the same inquiry through which the data on the service of the 
farm machinery was obtained for western New York, the repair 
charges against these implements were also accumulated. In all of 
the tables the total amount of repairs during life is given for each 
implement, corresponding to the same annual service for which the 
replacement and interest charges have been computed. The cost 
of repairs per year, per day actually used, and per acre can be 
readily computed. Tables II to XIX afford complete data, therefore, 
for this area, on the machinery cost of farm operations. 
DETAILED STUDY OF IMPLEMENTS. 
WALKING PLOW. 
From Table II, for walking plows, it appears that the average 
plow used in this section is about 12 inches wide; that it averages 
32.9 acres of plowing annually, and lasts on the average 11.7 years. 
During this time it covers an average of 384.9 acres and is used a 
total of 224 days. Of all farm implements, the walking plow gives 
by far the most days of service. The heavier plows do more work 
annually. They also plow more acres and do more days of work 
before they are worn out. Since the walking plow is an implement 
of low cost, the interest charge is relatively low. Its long use reduces 
the replacement charge per acre, but the heavy work required of it 
makes the repair charge per acre equal that of a grain binder and 
exceed that for most of the other implements. 
