Owing to the control of erosion caused by rainwater, the lands have contour curvesthat make difficult the sprayer movement and stability. The sprayer's operator,besides driving, aligning in the paths between the plants rows, also looks forcontrolling the height of the boom sections in order to keep them from touching theground and at an appropriated height above the plants. This procedure causes greaterrors and variability of chemicals application, resulting in improper distribution anddrift. An electronic system to control the boom sections height, by means of multiplesensors, was developed and installed on the Jacto Uniport 2000 self-propelledsprayer. The system and the results of the tests in cotton crops are presented. Thedeviation values between the ideal spraying height and the actual boom height duringthe application, as well as the period and the distances traveled corresponding tothese deviation values are compared for the manual and automatic control operations.Higher travel speeds were tested.