Integrating crop management and crop rotation effects into models of weed population dynamics: a review

Current weed demography models were reviewed to evaluate how the effects of cultural practices on weed dynamics were integrated into the models and to suggest possible ways to improve the simulation of cropping system effects . Several models were chosen to illustrate the interactions between croppin g systems and weed dynamics. The first one described the structure of the w eed life cycle. The second model integrated the effects of a wide set of cu ltural practices; the comparison of this example with other models suggeste d how the integration of cropping system effects could be improved. The las t two models introduced the interactions of cultural practices with intrapl ot weed variability either spatial variability of weed densities or generic and phenotypic variability within weed populations, This review indicates some ways to make weed population models more comprehensive, robust, and ac curate in order to improve their contribution to the evaluation and managem ent of cropping systems.