Computerised decision support systems: Aids to rational and sustainable weed management

Computerised decision support systems offer an ideal means of achieving economical, environmentally safe, and sustainable weed management. Systems based on weed economic threshold concepts have been developed in the United States and Europe. In several of these, weed density is the sole variable used for estimating crop yield losses due to weeds. In Canada, there have been few attempts to develop computerised decision support systems to facilitate rational weed management. A notable exception is a microcomputer program developed by the Manitoba Department of Agriculture for assessing the economics of wild oat (Avena fatua L.) control in cereal and oilseed crops. A relative time of emergence variable is a crucial component of the program. There is a need to develop a more comprehensive system for managing multiple weed species in a range of crops grown in Canada. For reliable recommendations to be made, input requirements for the system should include information on the relative time of emergence of the crop and weed, crop density, environmental factors and method of fertilizer application, as well as weed density. In terms of output, the system should indicate realistic weed monitoring procedures, and the long-term bioeconomic implications of seed production by uncontrolled weeds.