Local MAPs activities highlighted that the socio-economic context is a major driver for the type of species mixture grown, in contrast to the information generally found in scientific literature that rather focuses on the mechanistic understanding of interspecific interactions.
The ‘four C’ approach (Competition, Complementarity, Cooperation and Compensation) was used to analyse the final outcome of plant-plant and plant-environment underlying ecological interaction mechanisms. The differences in plant traits and partial separation of the time period during which two or more species are cultivated together are the main drivers for the niche differentiation and/or facilitation that contribute to yield gains or increased resource use efficiency in intercrops.
There is still a lack of information on mechanisms at work in species mixtures to reduce weeds, animal pests and diseases, and hence contribute to the reduction of pesticide needs. Indeed contrasted results were obtained in field experiments about effects of intra- and interspecific mixtures on biotic interactions due to pests and beneficial organisms.
New ideas on breeding for intercropping were developed: the theory of hybrid breeding in maize based on the "general mixing ability" (GMA) and the "evolutionary plant breeding" (EPB) methods. Key-traits and defined ideotypes were identified for good performance in species mixtures, developed assessment tools for species mixture performances, screened existing varieties to estimate their mixing ability, and estimated and compared the genetic gains of new breeding schemes that will include key-traits, GMA and EPB approaches.
Modeling was used as the key tool for representing the functioning of species mixtures. Different types of models were developped: (1) functional-structural plant models, (2) process-based classical crop models (STICS, Florys) adapted for intercropping, (3) empirical models directly using data from experiments, and (4) expert-based qualitative models. Simulations illustrated the potential of species mixtures to be better adapted to variable water availability than sole crops, and the role of plant trait combinations conferring high yields, high resource use efficiency, good levels of pest control, and high productivity and resilience under higher weather variability caused by climate change.
Practical information was also produced on intercropping by assembling information from across ReMIX results and many other past and present EU and national projects into a tool box available to all (www.agrodiversity.eu). Specific guidance on settings for combined harvesters for intercropping have been provided, thus solving an important technical problem. Prototypes of decision support tools and teaching material, such as Interplay serious Game and Ecosystemix for ecosystems services assessment, were designed and validated with farmers and advisors.
Activities of dissemination were achieved to reach a wide range of publics: i) farmers, advisors, stakeholders and end-users through the organization of project events such as workshops and trainings in MAPs and 29 practices abstracts, ii) scientists and policy-makers with the organization of two final conferences in collaboration with the Diversify twin project, iii) students with a one-week virtual training school on intercropping, iv) general public and citizens with the use of social media (Twitter, Facebook groups), website, and newsletters, and a “YouTube channel” to broadcast project videos.
