Agronomy Library > Annual Weeds

Problem Weeds & Promising Herbicides - Direct Seeding Advantage 2006
Author: Ken Sapsford, University of Saskatchewan
Date Created: November 22, 2006
Last Reviewed: March 01, 2007
It was thought that once we adopted a reduced tillage then a direct seeding system that we would have a large shift in our weed population. To date we have not seen the large shift. Weed surveys over the past 35 years have shown the top 4 weeds have remained the same, green foxtail, wild oat, wild buckwheat and Canada thistle. Six species that have declined in the surveys are cow cockle, corn spurry, bluebur, night-flowering catchfly, flixweed and wild mustard. Five species that have appeared in the top 20 since 1990’s survey are cleavers, wheat, kochia, barnyard grass and dandelion. (J.Y.Leeson 2005). In general the relative abundance of annual grasses and perennials have increased while the annual broad-leaved species and winter annuals have decreased.  At the University of Saskatchewan over the past number of years we have been conducting research a number of weed species including three problem weeds: Dandelion, Foxtail barley and Kochia. Open the PDF for the complete paper