A 100-ptohp tractor equipped with instrumentation for monitoring vehicle operating parameters and energy inputs to implements powered by the tractor was used to measure the energy requirements of selected implements typically used in cotton production. Tractor engine speed was maintained constant at 2200 rpm, and ground speeds were typical of those used with the particular tractor-implement combination. Parameters monitored included fuel consumption, implement draft, drive axle torque, drive axle angular velocity, ground speed, and engine rpm. Typifying the results, a 9-shank 3-point chisel plow operated in a silt loam soil which had been disked immediately prior to chiseling required a draft force of 5030 pounds and resulted in a drive wheel slip of 12.5 percent. The same implement operated in the same soil type but without prior surface tillage required a draft force of 5870 pounds, but drive wheel slip was reduced to 10.3 percent.