The Structure of Weed Communities in Saskatchewan Fields

Abstract
This paper describes the communities of weeds in cereal and oilseed crops in Saskatchewan, using data collected in a 4-yr survey that sampled more than 400 fields. The survey data for the 40 most common weeds were analyzed in an attempt to distinguish natural groups of weed species and to compare the weed communities associated with the different crops and with different soils. The crops were barley (Hordeum vulgareL.), flax (Linum usitatissimumL.), oats (Avena sativaL.), rape (Brassica campestrisL.,Brassica napusL.), and wheat (Triticum aestivumL.). Phytosociological association and cluster analysis indicated that the associations of the weed species were more or less independent of the crop, although some differences existed and were determined more by soil or the associated climate. The 40 most common species were divided into three groups related to the soil and climatic subregions of the province.