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Alfalfa (Medicago sativa) Seed Yield Loss Due to Canada Thistle (Cirsium arvense)

  • James R. Moyer (a1), G. Bruce Schaalje (a1) and Peter Bergen (a2)


Alfalfa seed yield and Canada thistle densities were measured in 10 fields in southern Alberta to assess the effect of thistles on seed yield. Thistle density and seed yield from each field were fitted to the Weibull, hyperbolic, and linear equations and a random coefficient and linear equation were used to obtain an “average yield loss curve”. Estimated average losses in alfalfa seed yield were >34% and >48% at thistle densities of 10 and 20 shoots m–2, respectively.



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Alfalfa (Medicago sativa) Seed Yield Loss Due to Canada Thistle (Cirsium arvense)

  • James R. Moyer (a1), G. Bruce Schaalje (a1) and Peter Bergen (a2)


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