Date of this Version
Agronomy 2020, 10, 391; doi:10.3390/agronomy10030391
The main objective of this study was to identify optimal burner orientation for a newly designed flame cultivator by quantifying the flame temperature distributions of cross, back, and parallel position of burners at diﬀerent heights of the soybean canopy (distance from the soil surface). Flame temperatures were measured within-row for three burner orientations at seven propane doses (20–100 kg/ha) and eight diﬀerent canopy heights (0–18 cm above soil surface). Soybean plants in V3 growth stage were flamed with the same doses and burner orientations, and 28 days after treatment (DAT) crop injury (0%–100%), plant height (cm), dry matter (g) and grain yield (t/ha) were assessed. All three burner orientations had high flame temperatures at lower canopy heights (high) that gradually decreased with increasing canopy height (6–18 cm). Measured temperatures ranged from 33 to 234 °C for cross flaming, 29 to 269 °C for back flaming and 23 to 155 °C for parallel flaming, with high variability in temperature patterns. Back flaming generated flame temperatures above 100°C at a lower propane dose (27 kg/ha) compared to cross and parallel flaming (40 and 50 kg/ha). For all tested parameters, parallel and cross flaming had better impact on soybeans than back flaming, but for weed control in crop rows, cross flaming is recommended.