Demography and population dynamic of the arable weed Phalaris brachystachys L. (short-spiked canary grass) in winter wheat

The demography of the annual grass weed Phalaris brachystachys (short-spiked canarygrass) was studied during three consecutive years in winter wheat in south Spain. The average density was 16.70 seedlings m−2. The rate of seedling recruitment was 0.18. Average seedling survivorship was estimated with a value of 0.3 and was relatively uniform. Plant fecundity was calculated at 1232 seeds plant−1. The annual rate of population growth was estimated based on the above-mentioned parameters. The growth rate obtained was very high (λ=75.96), indicating the high potential of P. brachystachys to increase its populations in the absence of control measures. Sensitivity analysis indicated emergence, survivorship and seed losses were most sensitive to parameter variation. Management practices that reduce these parameters may result in reductions in weed populations.