air seeders as reported in Table 3 suggest that the relative cost difference between conventional
and no-till equipment depends upon machine size. A 10-foot no-till drill costs almost three times
as much as a 10-foot conventional drill. And, a 20-foot no-till drill costs more than twice as
much as a 20-foot conventional drill. However, a 36-foot no-till air seeder costs only 30% more
than a 36-foot conventional air seeder.
MACHSEL is a machinery complement selection software program developed by Kletke
and Sestak. It enables a user to assemble a set of tractors and machines that can perform the
budgeted field operations in the expected time available. For this study, fieldwork day
probability distributions based upon historical weather of central Oklahoma and clay loam soils
were used (Kletke and Sestak). The 85% probability level was used meaning that machines were
sized to accomplish the work in the appropriate time period in 17 of 20 years. Candidate
machines were selected based on farm size, estimated fieldwork days, machines available, and
required field operations.
The machinery complements do not include combines and trucks. It was assumed that all
wheat produced would be custom harvested and hauled, typical for the area. Custom application
of herbicide, fertilizer, and insecticide was budgeted for the 320 and 640-acre farms at prices
reported in Table 2. Custom application of these inputs was not assumed for the two large farms.
The machinery complements for the 1,280 and 2,560-acre farms include fertilizer applicators and
sprayers.
Table 4 includes a list of the selected machines for each farm size for both production
systems. Parameters, including field efficiency, draft, speed, repair factors, and depreciation
costs, were based upon Agricultural Machinery Management Data Standards estimates as
published by the American Society of Agricultural Engineers (ASAE). Diesel fuel price was