HEAT-APPLICATOR MACHINE FOR WEED CONTROL

ABSTRACT Pesticide environmental risks and increased weed resistance have encouraged studies for alternatives to herbicides. Among these are weed thermal control methods by controlled heat application machines. Thus, this study aimed to test a prototype of heat-applicator machine as a function of changes in gas pressure, travel speed, and tire traffic effect on plants. Then, three experimental factors were tested: gas pressure (98, 196, and 245 kPa), travel speed (0.56, 0.78, and 1.17 m s−1), and tire traffic effect on plants (with and without traffic). The results showed that tire traffic effect on plants and subsequent heat application had no effect on control rate. Weed control rates reached levels considered satisfactory using a heat application speed of 0.56 m s−1 associated with gas pressures of 245 or 196 kPa, as well as a heat application speed of 0.78 m s−1 associated with a gas pressure of 245 kPa. A total between 60.9 and 84.9 kg ha−1 liquefied petroleum gas was required for weed control of around 80%.