Design of weed management systems with a reduced reliance on herbicides poses new challenges and prerequisites for modeling crop-weed interactions

Ecophysiological models for interplant competition were first developed in the early 1980s to obtain a better understanding of the harmful effect of weeds on crop productivity. The models were developed from simulation models of monoculture crops; each competing species was represented by its own growth model, which were then linked by additional routines to account for the distribution of resources over competing species. Initially the models were used for the construction of more robust damage relationships to support rational decision making on the use of herbicides. At present, apart from a need to reduce the use of herbicides, the design of weed management systems with a reduced reliance on herbicides is advocated. As a result, the weed problem should be envisaged in a different perspective. Rather than focusing only on detrimental effects in current crops, main emphasis should shift towards the management of weed populations and weed management itself should become an integrated component of crop management. For the development of these alternative management systems, specific improvements with respect to prevention, alternative control technology and decision making seem promising. The new challenges for modeling crop-weed interactions and prerequisites for crop-weed competition models that follow from these developments are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.