Weed Competition

Weeds compete with crop plants in several different ways. First there can be interference competition where there is physical exclusion from some aspect of the shared habitat. Second there is exploitation competition, which is indirect, and takes the form of competition for a wide variety of resources such as light, water and nutrients. There may also be allelopathic competition where the weed produces phytotoxins that reduce or inhibit the growth of the crop. Two types of models are used to measure crop loss caused by weeds, density based models and mechanistic models. The former are descriptive whereas the latter requires a quantitative insight into the dynamics and mechanisms of competition.