Document Type : Research Paper
Authors
1 Assistant Professor, Department of Agricultural Machinery Engineering, College of Agriculture, Ferdowsi University of Mashhad, Iran
2 Assistant Professor, Department of Agricultural Machinery Engineering and Mechanization, Shahid Chamran University of Ahvaz, Ahvaz, Iran
Abstract
Replacement of tractors is a very difficult task. Farm managers often need to make such economic decisions about their machines. Repair and maintenance expenditures can have significant impacts on these economic decisions and forecasts. The purpose of this research was to identify a regression model that can determine economic life of two-wheel drive tractors. The study was conducted using empirical data on 60 two-wheel drive tractors from Astan Ghodse Razavi agro-industry during the years 1988 to 2005. A power model was selected as the best model for prediction of repair and maintenance costs. Based on the power model, the cumulative cost model (CCM) was used to predict the tractors economic life. 29025 hours was predicted as the economic life of the tractor by the CCM model, while according to cost minimization model (CMM) this parameter was equal to 27773 hours.
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