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 w eeds on crop productivity. The models were developed from simulation models of monoculture crops; each competing species was represented by its own gr owth model, which were then linked by additional routines to account for th e distribution of resources over competing species. Initially the models we re 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 syste ms with a reduced reliance on herbicides is advocated. As a result, the wee d problem should be envisaged in a different perspective. Rather than focus ing only on detrimental effects in current crops, main emphasis should shif t towards the management of weed populations and weed management itself sho uld 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 pro mising. The new challenges for modeling crop-weed interactions and prerequi sites for crop-weed competition models that follow from these developments are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.