12


 Line No. Col. 3 Col. 15 Col. 16
 March Unit Item
 (Power Code)
 (38) Disk 2. 2. 35.
 (39) Plow 1. 2. 31.
 (40) Disk 1. 0. 35.

These entries would indicate that two trips over the field are made in

March with the disk and that one trip is made with a plow with a disk

hooked behind it. No entry is made for the power unit, column 15, for

the disk following the plow since the entry of a power unit for this item

would result in double counting. There is also no reason why several

tractor sizes might not be used, pulling a disk or plow with a large

tractor and a planter with a smaller tractor.

 Similarly, if plowing were done only every other year rather than

annually, the entry from the sample budget would become

 Line No. Col. 3 Col. 15 Col. 16
 March Unit Item
 (Power Code)
 (39) Plow .5 2. 31.

indicating that the plow is used, on average, one-half times per acre

per year, or once per acre in two years.

 Often power units are used without implements. Combines, for example,

seldom pull implements. Their use is specified on a timesover basis,

exactly like the implements, but no power unit is specified. For pick-ups

and trucks, however, an allocation on a times-over basis makes little

sense. Thus, for these machines the allocation is made on an hours per

acre basis. Assuming the truck is used along with the combine at a rate

of one-fourth hours per acre for August harvest, the appropriate entries