The weed flora of arable fields in Alberta is largely the result of the accidental or intentional introduction of many alien species as documented by weed surveys from the 1900s to the 2000s.  New crops, extended rotations, summer fallow reduction, conservation tillage systems, efficient fertilizer use, and enhanced herbicide options have been introduced during the last few decades.  The adoption of these farming practices would be expected to change the arable weed flora over time.  The weed flora would also be expected to vary among agroecoregions due to climatic differences.  Changes in the regional weed flora may also occur by the range expansion of species already present.  To track these changes, a long-term monitoring program is required.  This paper illustrates the long-term changes in frequency, abundance, and distribution of weed species in Alberta. 

Download the PDF file for the full paper from the Agronomy Update 2008 conference proceedings