Effects of tillage and herbicides on direct-seeded onion (Allium cepa)
Early-season weed control and a companion crop such as barley (Hordeum vulgare) are needed in direct-seeded onion due to slow seedling emergence and the potential stand losses from wind erosion of soil particles. However, if the companion crop is not removed at the appropriate time, it becomes a weed and competes with onion to reduce yield. If compatible with early-season weed control methods, strip tillage may enable the grower to eliminate the companion crop. Field experiments were conducted to evaluate the effects of tillage and herbicides applied prior to onion two-leaf growth stage on broadleaf weed control in onion (Allium cepa L.). Common lambsquarters (Chenopodium album L.) densities were lower in strip tillage compared to conventional tillage up to three weeks after the post-emergence applied herbicides. In general, post-emergence herbicide treatments provided greater early-season broadleaf weed control than pre-emergence herbicide treatments. Onion yield and grade did not differ among herbicide treatments because the mid-season herbicide application provided sufficient control/suppression of the early-season weed escapes that these initial weed escapes did not impact onion yield or bulb diameter. Tillage affected onion yield in 2007; onion in strip tillage treatment were larger in diameter resulting in greater total and marketable yields than conventional tillage. Results indicate that strip tillage use in onion production was beneficial, especially when growing conditions were conducive to higher yields and that the use of strip tillage in onion should provide an alternative to using a companion crop as it did not interfere with either early-season herbicide system.
Gegner-Kazmierczak, S. and Hatterman-Valenti, H.M. 2015. Effects of tillage and herbicides on direct-seeded onion (Allium cepa). Acta Hort. (ISHS) 1105:205-212
common lambsquarters (Chenopodium album), redroot pigweed (Amaranthus retroflexus), hairy nightshade (Solanum physalifolium), herbicide reduced rates, strip tillage