Effectiveness of flame weeding and cultivation for weed control in organic maize

Abstract

Weed management is a major constraint in organic crop production. Propane flaming combined with mechanical cultivation in a single operation could be an additional tool for weed control in organic maize. Field studies were conducted on the certified organic field at the Haskell Agricultural Laboratory of the University of Nebraska–Lincoln (UNL), Concord, NE, USA in 2010, 2011 and 2012 to evaluate the effect of flaming and cultivation within two fertility regimes (with and without manure) on the level of weed control and grain yield of organic maize. A total of 12 weed management treatments (WMTs) were applied at the 3-leaf (V3) and/or the 6-leaf (V6) growth stages of maize that included a weed-free control, weedy season-long, and 10 combinations of mechanical cultivation (inter-row), banded flaming (intra-row) and broadcast flaming (intra- and inter-row area). The treatments were applied utilizing flaming equipment developed at the UNL. All evaluated parameters (weed control, weed dry matter, crop injury, yield and yield components) indicated that there was no interaction between manure application and WMT; however, manure application increased maize yield by 1.1 t ha − 1. Overall, maize showed good tolerance to all flaming treatments averaging only 5.1% and 3.6% crop injury at 28 days after treatment in no-manure and manure plots, respectively. The best weed control was achieved with banded flaming followed by aggressive cultivation, providing over 90% weed control and yields of 7.8 t ha − 1, and flame-cultivation conducted twice as a single operation, giving 88% weed control and yields of 7.5 t ha − 1, conducted twice at the V3 and V6 growth stages. Broadcast flaming conducted twice provided 70% weed control and yielded 6.0 t ha − 1. These results suggest that flaming and cultivation applied separately or combined in a single operation, as a single trip across the field, have a potential to be used for weed control in organic maize production systems.