ABSTRACT
The interaction between crops and weeds has received extensive study. The primary purpose of these studies has been to quantify the im pact of weeds on crops so that management of the weeds could be justi fied (Cousens, 1987; Zimdahl, 1980). In this contribution, we examine the ecological theories on interactions that may be important in structur ing plant communities in agricultural systems. Our focus is applied in that we are interested in interactions that have tangible results on our ability to achieve management objectives over short-and long-term time horizons. We argue that while the historic focus on understanding of competitive relationships between weeds and crops has lead to a more accurate understanding of the short-term cost of weeds, the impor tance of competitive interactions in structuring weed communities in agroecosystems remains unclear. We will briefly outline the logic be hind the ecological models of plant interactions and dynamics from the scale of the individual through the community, highlighting areas we consider to be particularly relevant to the design of ecologically sound management practices.
