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In this study, the effect of three factors namely motor type, irrigation method, and farm size on irrigation costs, were studied, using factorial analysis
of variances method. The needed data applied in the study were collected using Multi Stage Stratified Sampling of farmers during 1375-76 cropping
season. The study sample included 97 wheat producing farmers, electro-pump and diesel motor-pump users, in Shiraz city of Fars province. Results indicated
significant difference between irrigation costs, using electro Vs. diesel motor-pumps and for different rrigation methods, and farm sizes. Also,it was
found that the benefit-cost ratio of substituting the electro-pumps with diesel
motor-pumps for small, medium and large farm sizes was greater than unity.
Therefore, these transfers will be beneficial. But, if there were large distances between nearest electrical power supply and farm land, substitution will only
be profitable with maximum transfer costs of 607403, 12404260 and 21607800
rials for small, medium and large farm sizes, respectively.