Survey of yield losses due to weeds in central Alberta

Weedy and weed-free yields were determined in fields of barley, canola, and peas in Lacombe County, Alberta, Canada from 1995 to 1997. Yield losses were most frequent and severe in peas, and least frequent and less severe in barley. Yield losses due to weed competition were not detectable at 33, 60, and 73% of the pea, canola, and barley sites, respectively.