Weed communities in organic and "conventional" wheat fields
Weed communities were assessed in organic wheat fields and in nearby fields managed with chemical inputs ("conventional"). The weed species that were most abundant (green foxtail, wild buckwheat, Russian thistle, redroot pigweed, stinkweed) were common to both systems, and to both years of the study. Wild oat and kochia were relatively more abundant in "conventional" fields; lamb's-quarters and wild mustard were relatively more abundant in organic fields. Organic fields had, on average, 1.6 times the number of species and 3 times the number of individual weeds compared to nearby "conventional" fields. Producers that managed fields organically used summerfallow and tillage to the same extent as their "conventional" neighbours. Organic wheat fields were seeded later than "conventional" fields. The crop rotation for organic fields was more likely to include legumes and cereals other than wheat; "conventional" fields were more likely to be monocrop wheat or to include canola or mustard. Producers of organic wheat perceive a greater range of weed control options than their "conventional" neighbours, and a majority do not consider their difficulties with weeds to have increased since they adopted an organic system.
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