Weed management using crop competition in Australia.

Adoption of conservation agriculture has brought significant changes in crop management in Australia. Increased reliance on herbicidal weed control is one of the most significant changes that have occurred throughout Australian cropping systems. The singular focus on herbicides for weed management has led to the frequent and widespread evolution of herbicide resistance in several weed species. Herbicide resistance means the loss of herbicide resources and as new herbicides modes of action are unlikely then use of alternative non-chemical cultural weed management options is essential. Crop competition is an approach that can be used to manage weeds for improved crop production. Enhanced crop competition can be achieved through the use of competitive crop species and cultivars, increased seed rates, narrow row spacing, and altered row orientation. These options are already routinely used in Australia and are proven in their ability to reduce weed biomass and fecundity. Although these strategies have been successfully used in Australian cropping systems, the research has frequently been focussed locally and not extrapolated more broadly throughout the Australian grain production region. Crop competition can potentially be a sustainable weed management option in reducing the reliance on herbicides and combating herbicide resistance and therefore, needs to be considered in all integrated weed management plans. [ABSTRACT FROM AUTHOR]