Impact of single and repeated flaming on yield components and yield of maize

Weeds are a major yield-limiting factor in both conventional and organic crop production systems. In maize (Zea mays) production, propane flaming could be used as an additional tool for weed control. Thus, maize tolerance to single and repeated flaming was studied with eight treatments, which included the following: nonflamed control and broadcast flaming conducted once at V2 (two-leaf), V4 (four-leaf), and V6 (six-leaf) stage, two times (each at V2 and V4, V2 and V6, and V4 and V6 stages), and three times (at V2, V4, and V6 stages). All the plots including the nonflamed control were maintained weed-free during the entire growing season by hoeing as weeds appeared. A propane dose of 50 kg ha−1 was applied with torches parallel to the crop row and at an operating speed of 4.8 km h−1 for all treatments. The crop responses evaluated were crop injury at 7 and 28 days after treatment and effects on yield components and yield. Maize exhibited excellent tolerance to single and double flaming regardless of the growth stage. However, the triple flaming resulted in more than 30 % injury. Maize flamed once and twice produced between 11.1 and 11.6 t ha−1 yield, which was statistically similar to the yield obtained from the nonflamed control (11.7 t ha−1). Maize flamed three times yielded 9.9 t ha−1, which was 8.5 % lower compared to the nonflamed control yield, and likely would not be acceptable by producers. Results of this study indicate that maize is able to tolerate up to two flaming treatments per season without a loss of yield.