The aim of this investigation was to find out the optimum tractor power requirement under Libyan agricultural conditions in order to suggest the most suitable tractor power for the majority of Libyan farmers. A comparison was carried out between two tractor power level, 47HP and 75HP, for the sake of locating the optimum power that could provide the farmer' with his basic needs for a progressive mechanized operations under specific condition. The tested parameters were drawbar pull, slip percentage, fuel consumption, and maneuverability. The lowest wheel slip percentage was recorded with tractor 47HP when operating all implements except with the chisel plough 2st pass. Also it was clear that, there was significance different between the mechanical elements with different types of power that the lowest wheel slip percent was obtained by chisel plough first pass and land leveler. It was clear that the tractor 75HP when currying different equipment, that the fuel consumption (measured in l/h) was higher than the tractor 47 HP. The actual field capacity of tractor 75HP was significantly higher than that of tractor 47HP with different implements.Also it was evident that the field efficiency when tractor 47HP is executing the 1st pass with chisel plough was higher than the efficiency with implemented. Also it was evident that the efficiency when tractor 75hp is executing others the chisel plough 2nd pass is higher than the efficiency with other implements. Also it was evident that the efficiency of tractor 47HP is greater than the efficiency of tractor 75HP in deferent operations.
The higher efficiency obtained by 47HP, where the lowest efficiency was recorded with disc plough. The 47HP rating tractor provided the higher value of efficiency in all the tested operations. Consequently it is more suitable for the tested mechanized operations.