The main objective of WP Competition is to assess and describe the efficiency of the competition process to suppress creeping perennial weeds. Focus will be on the performance of cropping systems that enhanced competition by using subsidiary crops, and intercrops. AC/DC-weeds will undertake a global quantitative analysis of all available data on subsidiary crops in cropping systems to assess the overall benefits and limitations of competition effects on perennial weeds. Our analyses will help to understand, whether the competition success is dependent on the species of subsidiary crops or on main crop management, and if there is a generic process of the competitive effect on perennials (whatever the cover crop – cropping practices combination is). It is crucial to understand why cropping practices are successful or unsuccessful to choose an efficient solution to manage perennial weeds.
Firstly we will assess the performance in terms of weed regulation by competition effects: intensity of weed suppression, spread and establishment of the creeping perennials and, if achievable, crop yield reduction by perennials. We will use a meta-analysis on literature and an analysis of published system experiments. We will focus on establishing relationships between competition management and reduction of perennial weeds.
Secondly, we will study the literature and experiments in details to identify and select traits of the candidate subsidiary crop species or species mixtures capable to compete with perennial crops. Trait identification will be conducted by a method developed in France, which links the traits of species to the services they provide.