Use of thermal images for optimizing burner height, operating pressure, and burner angle of a weed flamer

Abstract

A two-meter wide prototype weed flamer was developed as a tool for thermal weed control. The weed flamer consists of an LPG tank, pressure regulator, back pressure valve, flow valves, and burners. The burner adjustments are flexible with height setting from 0 to 450 mm and flame angle setting from and 0 to 90°.The thermal camera images were studied at different heights (150, 200, 250, and 300 mm), burner angles (30 and 45°), and pressures (0.1, 0.15, 0.2, 0.25 MPa) to determine the best settings under stationary operating conditions. Based on thermal camera image results, it was found that the burner should be set at 200-250 mm with 0.2-0.25 MPa to obtain the highest temperatures and longest flames. The initial tests of the gas burning system were completed as a broadcast flaming machine and gas doses from 15 to 90 kg ha^-1 were applied from 0.25 m above the ground at 30° flaming angle at 0.2 MPa. The doseresponse curves of a weed (Convolvulus arvensis L.) were generated to determine the effectiveness of the weed flamer. C. arvensis could be controlled with gas doses from 40 to 82 kg ha^-1 depending on the growth stage at 14 day after treatment (DAT). The theoretical field capacity of the 2 m wide flamer varies from 0.32 to 1.62 ha h^-1 depending on the gas dose to be applied.