Combined mechanization systems of primary tillage (plows) and planting methods (manual and mechanical) for cotton crop were studied on clayey soil. Strain gage instrumentation, as a measuring technique, was used to measure the pull force and the torque at left and right rear wheels of tractor for cotton seed-bed preparation. Also, the penetration force was measured before and after tillage operations and soil clods were measured after tillage. In addition, the yield was determined at picking times where the picking was manual. Statistical analyses of these data showed that the best combina­tions were "moldboard plow at 5km/h + manual planting "," chisel plow at 5 km/h + manual planting "," chisel plow at 5 km/h + planter "and "chisel plow at 4 km/h + planter respectively. Also, the torque ratio be­tween left and right wheels was unity with chisel plow and eight times with moldboard plow. The power ratio between rear wheels axis and drawbar was equal to two with chisel plow and four with moldboard plow.