Determining and analyses Economic useful Life for Agricultural tractors in the West Azerbaijan province

Estimating useful life of agricultural machines is the main factor in applications of these devices. Decision making about replacement of used farm equipment is one of the important items in farm machinery management. Repair and maintenance costs are related to tractor age and using hours. The useful life for all agricultural machines set was produced the tables in developed countries. This study was conducted to estimate useful life for agricultural tractors to estimate the repair and maintenance cost and suitable mathematical model in the West Azerbaijan province. The popular model in this area includes three models Massey Ferguson 285, Massey Ferguson 399 and universal U650. Obtained data was including, repair and maintenance costs, annual usage in the hours and initial purchase price. Amount of accumulated depreciation and capital and profits as accumulated capital costs and maintenance tractors calculated for each model and economic life of tractor, respectively.