While weeds in sugar beet farming reduce crop yield and quality, they also lead to higher labor and material losses. In recent years, in order to eliminate or reduce the damage caused by weeds in sugar beet farming, weed control has gained importance. To this end, various studies have been conducted on robotic weed control by detecting weeds using image processing algorithms and hoeing or spraying the weeds. In this study, weeds in sugar beet fields were detected by the image processing algorithm and were sprayed with a liquid. When height of spraying nozzle above the ground was 30 cm and 50 cm, measurements of spraying robot were carried out for 8 different speeds. The weed surface covering area of spraying liquid was evaluated by two different methods. A decrease of 40% in nozzle height of smart spraying robot caused a decrease of about 12.18% at 4 different weeds surface covering area (cm(2)) of spraying liquid and a decrease of 16.70% at weed surface covering area (pixels) of spraying liquid.