a determining of optimum size of potato farms in hamedan province (a case study, bahar city area)

potato is one of the most essential nutritious food products for many people in the world. it is very important in the food basket of the iranian families as well. ardabil, isfahan and hamedan are the main potato growing provinces in iran. hamedan province ranks first with respect to yield. regarding the existing high potential in this province, an economic evaluation of this product would be indispensable. the aim of this study is to investigate the economic of scale in bahar (hamedan) area. the farmers are thus devided into three groups as according to usage of machinery during different farming stages. for each group, the cost fnuction was estimated and while using the function coefficients, the economic of scale was applied. the cross sectional data for the present study were collected through a two stage cluster sampling method. the sample included 155 potato farmers. the results indicate that the optimum size for a profitable potato farm, is more than the size presently cultivated by farmers in all the three groups. accordingly, an increase in the area under cultivation by farmers is recommended to achieve an effective measure in improving the total factor productivity as well as cost minimization.