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In this paper, we use conceptual insights from the actor–network theory (ANT) to explore the role of agroecological innovation systems (AeISs) in the reconfiguration of agricultural practices toward sustainability. AeISs are actor networks involving a diversity of individuals (e.g., farmers, traders, experts) and organizations (e.g., cooperatives, rural development agencies, teaching and research institutions) that mainstream agroecology principles and practices to enhance agroecosystems’ resilience. Their composition and structure affect the way different agents of change interact, as well as how they access, exchange, and use knowledge as they drive the adoption of specific technologies. We document seven AeISs that were active between 2005 and 2020 in the northern uplands of Laos. Within the framework of these initiatives, action research was conducted for understanding the processes underpinning diverse technical, organizational, and institutional innovations to foster an agroecological transition. Building on a comparative analysis of AeIS, we consider how agency was distributed among collectives as they reorganized in time. Our discussion highlights the importance of configuring, enlarging, and nurturing spaces in which actors are empowered to adjust and adapt, as well as to think and act collectively in complexity. Lastly, what counts in the innovation is the underlying networking process itself, i.e., the process through which all actors of the AeIS interact and exchange. Changes in the networking processes come with a changing conception of knowledge. Moving from knowledge to knowing (i.e., knowledge in the making), AeISs no longer only promote products or technologies, but also collective intelligence based on an ethic of care.

Land use and land cover have rapidly changed in Kham basin, northern Laos, with a rapid expansion of maize cultivated area. While maize monoculture has contributed to reduce rural poverty, many farmers are now confronted to declining yields, indebtedness, rising health and environmental concerns. Interventions at two different stages of the maize boom, i.e. expansion-intensification and distress-diversification phases, allowed capturing the main drivers of change in maize production systems, and assessing opportunities and constraints for the adoption of more sustainable maize-legume mixed systems. The successive innovations in maize cropping systems, i.e. introduction of hybrid seeds, motorized tillage, herbicides, service provision, planters, and mineral fertilizers, were mainly driven by productivity and profitability objectives. Farmers’ interest in maize-legume mixed systems was low during maize expansion-intensification phase. The decline in maize profitability and new market outlets for legumes open new opportunity windows for maize-legume mixed systems. Yet, farmers’ adoption of such systems is limited by (i) local perceptions of legumes as cash crops only, and (ii) farmers’ least effort strategies that includes e.g. heavy herbicide use and livestock free roaming after maize harvest. Large-scale adoption of maize-legume mixed systems requires innovative intervention mechanisms to engage local stakeholders into redesigning their landscapes and value-chains.

Rapid changes in agricultural systems call for profound changes in agricultural research and extension practices. The Diagnosis, Design, Assessment, Training and Extension (DATE) approach was developed and applied to co-design Conservation Agriculture-based cropping systems in contrasted situations. DATE is a multi-scale, multi-stakeholder participatory approach that integrates scientific and local knowledge. It emerged in response to questions raised by and issues encountered in the design of innovative systems. A key feature of this approach is the high input of innovative systems which are often although not exclusively based on conservation agricultural practices. Prototyping of innovative cropping systems (ICSs) largely relies on a conceptual model of soil–plant–macrofauna–microorganism system functioning. By comparing the implementation of the DATE approach and conservation agriculture-based cropping systems in Madagascar, Lao PDR, and Cambodia, we show that: (i) the DATE approach is flexible enough to be adapted to local conditions; (ii) market conditions need to be taken into account in designing agricultural development scenarios; and (iii) the learning process during the transition to conservation agriculture requires time. The DATE approach not only enables the co-design of ICSs with farmers, but also incorporates training and extension dimensions. It feeds back practitioners’ questions to researchers, and provides a renewed and extended source of innovation to farmers.

Cover crop-based cropping systems have gained considerable attention in recent years because of the recognized benefits of increasing agroecosystem diversity to enhance ecological functions and agroecosystem services through positive effects between species. While agronomic tools and methods to assess these services in multispecies plant communities barely exist, trait-based approaches, originally developed in the field of comparative functional ecology, provide an appropriate framework to study the effects of plant diversity on agroecosystems. We present our theoretical and applied research conducted over recent years using a trait-based approach to help improve cover crop choice to sustain agroecosystem services in banana agroecosystems of the French West Indies. We first provide a conceptual framework for assessing expected agroecosystem services from cover crops in banana agroecosystems, i.e., weed control, plant-parasitic nematode control, improvement of the nutrient cycling and avoidance of interference for resource acquisition in banana (dis-service), based on plant effect traits. Then, we experimentally characterized a collection of cover crop species to identify their resource acquisition strategies and the potential trade-offs they reveal. More practically, we characterized the cover crop species according to their potential to deliver four agroecosystem services expected from banana/cover crop systems. We constructed functional profiles of the cover crop species, and compared these profiles to cover crop ideotypes to select the best-suited species for each service. Finally, we used "engineering traits" to help design and optimize design and management of cover crop species mixtures. These examples from our research demonstrate that functional, trait-based approaches have strong potential to tackle agronomic issues and to resolve fundamental and applied questions related to the design of multispecies cropping systems that optimize multiple services.

Over the past half-century, major efforts have been made worldwide to develop sustainable alternatives to agricultural tillage. In line with these efforts, two main research development initiatives have supported the experimentation and dissemination of conservation agriculture (CA) in Laos. Here we present the results of a 4-year monitoring and evaluation study conducted in 21 villages targeted for dissemination. In a context of rapid transition to intensive commercial agriculture in Laos, CA has become an important constituent of agricultural landscapes. However, there are significant variations in adoption rates across the study region. Statistical and qualitative evidence suggests that experimentation and adoption are not contingent upon farm-level variables such as capital, labor, age and education. While access to land helps shape local decision-making, the land tenure threshold under which farmers are not willing to experiment with alternative cropping systems is relatively low and highly variable in both space and time. Rather, experience and awareness of land degradation, production costs, social cohesion and leadership appear to be key factors in explaining most variations in local adoption rates. These results indicate that the practice of CA is not necessarily incompatible with smallholder farming. However, while complex crop associations and rotations are necessary for integrated weed control and reduced chemical use, their diffusion would require a broader transformation of the agricultural industry and the current market demand.

Cover plants are one of the means to increase the functional biodiversity of fields and to enhance the ecological functions of the communities. However, the design of cropping systems including cover plants relies largely on expert knowledge. There is a lack of methods to select the best suited cover plants according to their role in the agrosystem. We propose to use functional traits to select cover plants suited to sustain ecological services in the banana agrosystems of the French West Indies. Our objectives were (i) to characterize a collection of cover plants on a trait basis, according to their potential to provide the services expected in a banana agrosystem and (ii) to discuss the potential use of this characterization for the design of innovative multi-species banana cropping systems. In these systems, four main services are targeted, i.e. controlling weeds, controlling plant-parasitic nematodes, improving soil fertility and particularly N availability, and avoiding competition with banana for resource acquisition. Three experiments were conducted, under field and controlled conditions, to evaluate the potential of a collection of 28 tropical cover plants to achieve the functions related to these services. For each cover plant, a functional profile was constructed from a combination of plant traits that are easy to assess experimentally. It described plants’ potential to achieve the functions expected in a banana agrosystem. Functional profiles required for cover plant usages were also identified. The comparison of the plant functional profiles and the functional profiles required for their usages enabled us to select the best suited plants for each usage. However, these functional profiles rarely corresponded, meaning that a cover plant is rarely sufficient to achieve all the functions required for a usage. Functional complementarities obtained by the mixture of different species of cover plants are thus often required. Compared to classical approaches of innovative cropping system design based on the experimental testing of spatial and temporal plant combinations, such a trait-based approach saves time by focusing on a shortlist of cover plants best suited according to their functions in the agrosystem.