Document Type : Original Article


1 MA, Department of Agriculture, Islamic Azad University, Shooshtar Branch, Shooshtar, Iran

2 Associate Professor, Department of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

3 Department of Agriculture, Islamic Azad University, Shooshtar Branch, Shooshtar, Iran


Predicting the maintenance and management costs and replacement age of tractors in agricultural mechanized units, is important from several points. So, doing a timely agricultural operations, more accurate measure of the amount of income  including the cost of these items , determining the useful life of old tractors , replacement age, cost of the process changes and the possibility of examining the undesirable causes of increase in costs are considered. The main data collected for this study include: the amount of the annual maintenance costs which are obtained of three major maintenance costs (spare parts, maintenance fee, and lubricants). The amount of annual work of tractors is obtained, too. Separating the cost items shows that the cost of spare parts is highest among the total maintenance costs.  The final model obtained in this study compared with some other sources indicates that the cumulative amount of these expenses as a percentage of the original price of the model resource estimate is lower than other models. The main reason which has been reported is the difference of maintenance costs (especially in the early years of the operation of tractors) with an initial price of tractors in comparison with other sources.  Finally, the economic life of the machines (the optimal replacement age) was estimated for each model of tractor. Results indicate that among the three models, estimated useful life of the John Deere 3140 Tractor and TM155-Newhland has been minimum and maximum, respectively.


Bowers W & Hunt D,1970.Application of mathematical formulsas to repair cost data. Transactions of ASAE 13(6):806-809.
Dalsted N & Gutierrrez p,)1996(.The cost of owning and operating farm machinery .Agricultual and business management notes.
Derakhshan, M. (1386). Econometrics. SAMT Publication, 1st Volume. 3rd Edition. Tehran
Gleim JA ,Persinger KM,Carpenter TG,Holmes RG and Ozkan HE,)1989(.A Comparison of ASAE estimated tractor and combin repair and maintenance cocts of selected farmers.ASAE Paper No.89-102.
Morris J,)1988(.Estimation of tractor repair and maintenance cost.J Agric Engng Res 41:191-200.
Ward,S.M.,Mcnulty,P.B.,Cunney,M.B.(1985).Repair Costs of 2 and 4 WD Tractors,Transaction of ASAE,28,4,1074-1076.
Zaidi,M.A.,Zafar,A.W.,Sabir,M.S.(1992).A Mathematical model for repair and maintenance cost of agricultural machinery,AMA,23,3,70-72.