Is volunteer wheat an economic weed in annual winter wheat production?

Annual winter grasses are competitive weeds in winter wheat (Triticum aestivum L.) due to their similar life cycle, root system, and morphology. Volunteer wheat is clearly a weed when infesting a crop of a different species. However, should substantial expense be invested in reducing volunteer wheat in a subsequent wheat crop? The effects of volunteer wheat in winter wheat were investigated in three fields of the inland Pacific Northwest (PNW) during 2015 and 2016. Volunteer wheat was found evenly distributed in fields harvested with a commercial combine with a chaff spreader. The ratio of volunteer to seeded wheat density was constant even in high productivity areas that had higher wheat densities. Volunteer head densities ranged from 13 to 28% of total heads with a high of 66% found in chaff rows (formed in fields harvested without a residue spreader). Volunteer wheat produced between 8 and 19% of total yield. The productivity per head of seeded wheat was higher than volunteer wheat and volunteer wheat reduced seeded wheat yield in all fields. The estimated total yield loss across fields was 10.8%. Volunteer wheat may cause less yield loss than other winter annual weeds because of its contribution to yield. However, a 10% yield loss is significant and practices to minimize volunteer wheat in wheat fields are recommended.

Automated summary

Research found that volunteer wheat is evenly distributed in winter wheat fields, contributing to 8% to 19% of total yield; the yield loss caused by volunteer wheat significantly impacts the productivity of seeded wheat, with a total yield loss estimated at around 10.8%.