Corn \u3cem\u3e(Zea mays)\u3c/em\u3e and Soybean \u3cem\u3e(Glycine max)\u3c/em\u3e Tolerance to Broadcast Flaming

Propane flaming can be used as one of the alternatives to chemical weed control. A field experiment was conducted during summer 2007 at the Haskell Agricultural Laboratory near Concord, NE to determine the responses of corn (Zea mays) and soybean (Glycine max) to broadcast flaming utilizing different rates of propane. The 5-leaf corn (V5, plant height 25 cm) and V3 soybean (plant height 8 cm) were flamed using propane rates of 0, 12, 31, 48, 69 and 87 kg/ha. The responses of the corn and soybean plants were described by logistic models. In general, soybean was more susceptible to propane flaming than corn; 20% injury was achieved with 21 kg/ha in soybean compared with 46 kg/ha in corn. Dose response curves of propane for soybean were similar among evaluation dates. For example, the propane dose (also known as effective dose, ED), which caused injury levels of 5% (ED5), 10% (ED10) and 20% (ED20) at 3 hours after treatment were 11, 13, and 17 kg/ha, respectively, and these rates did not change significantly over time. In contrast, dose response curves were different over time for corn. For example, the ED20 values for 3 hours, 7, and 14 days after treatment were 14, 22, and 46 kg/ha, respectively, suggesting that the corn crop was able to recover after flaming. This is likely because the growing point at time of flaming was below the ground level and thus remained unaffected. Broadcast flaming for weed control has more potential for use in corn than soybean. Further research is needed to determine if these relationships are valid at other growth stages