From the ground up: Patterns and perceptions of herbaceous diversity in organic coffee agroecosystems

International audience1. Smallholder farms that transition to organic and biodiverse production are increasingly recognized as strongholds of agrobiodiversity, with emerging work identifying important outcomes such as enhancing crop portfolios, mitigating extreme climate events and contributing to farmer well-being. Yet the emergent herbaceous communities in these organic systems remain understudied, with the functional diversity and management of this stratum relatively unknown. 2. This study identifies the taxonomic and functional diversity of the herbaceous community in organic coffee agroforestry systems, and describes the extent of this diversity with farm, and farmer, attributes. We measured leaf-level functional traits (e.g. specific leaf area) of the herbaceous community to derive functional diversity indices and collected localized environmental conditions on 15 organic coffee farms in Central Valley, Costa Rica. We also conducted semi-structured interviews with nine farmers to construct mental models on herbaceous community management using a cognitive mapping approach. 3. In total, 38 species from 20 taxonomic families were present in these organic coffee systems. The herbaceous communities were functionally diverse; however, functional evenness increased with canopy openness, suggesting that farms adopting agroforestry tend to have a more functionally diverse herbaceous stratum. 4. Farmer perception of plant traits in the herbaceous community was differentiated into competitive (weeds) or neutral/positive effects. These perceptions aligned with well-established functional trait trade-offs. The mental models representing farmer decision-making processes were highly variable, with a nearly 30% increase in cognitive map density from the simplest map to the most complex; this complexity in mental models was a key explanatory variable in the level of functional diversity of the herbaceous community. 5. Organic management practices that support agroforestry practices also, in turn, promote a functionally diverse herbaceous stratum. We show that functional trait syndromes in these herbaceous communities in agroforestry systems are linked with farmer perceptions of traits, and that highly interconnected farm decision-making is related to greater functional diversity in the herbaceous community. Understanding pathways of farmer decision-making on managing this herbaceous community can appropriately situate on-farm practice and policy for the transition to organic production, and inform emerging agri-environmental programs

Combining participatory games and backcasting to support collective scenario evaluation: an action research approach for sustainable agroforestry landscape management

International audienceThe combined and interacting effects of land-use change, resource extraction and climate change threaten the sustainability of millions of mainly smallholder farms in tropical agroforested landscapes. In many of these landscapes, coordinated action among stakeholders at landscape level would help to address challenges such as pests and diseases, price crises and climate change. However, methods to facilitate the co-production of sustainable landscape management in such complex multi-stakeholder systems are currently largely lacking. In this paper, we present a novel approach to explore pathways for the sustainability transition of agroforestry systems. By combining participatory forecasting and backcasting approaches, based on serious games and future vision development, we explore relevant agroforestry management strategies for reaching sustainable future coffee-based agroforestry landscapes. We focused our research on the challenges faced in the main coffee-producing area in Nicaragua. Here, we organized five participatory game sessions to explore farmer decision-making processes, farming strategies and to develop new networks and stimulate social learning among farmers. In the associated backcasting workshop, the most influential game session participants joined technicians, researchers and municipality officials to collectively envision sustainable future landscape management. In all game sessions, farmers developed diversified coffee-based agroforested landscapes characterised by increased density and diversity of shade trees, for the purpose of income diversification as well as forest conservation. During the backcasting workshop, the participants identified policy instruments and community-based solutions for the transition to sustainable landscapes. Our participatory approach facilitated discussion on landscape planning among farmers and other stakeholders and allowed the outline of a pathway towards the collective envisioned future landscape. The combination of participatory forecasting and backcasting proved to be a helpful tool to support multi-stakeholder processes towards sustainable landscape management in this and other complex landscapes

Coffee agroforestry systems that reduce crop losses due to pests and diseases, while providing ecosystem services

National audienc

Analysis of interactions amongst shade trees, coffee foliar diseases and coffee yield in multistrata agroforestry systems

International audienceIn complex coffee-based agroforestry systems, quantifying the impact of shade trees on coffee disease regulation and coffee yield is crucial for improving these systems and designing more sustainable ones. To this end, we analyzed interactions amongst shade trees, coffee plants (cv. Catimor), the coffee foliar disease complex and soil characteristics. We studied systems characterized by 40 variables measured in 60 plots located on three farms (monitored for 2 years) in Nicaragua. These variables characterized six system components grouped in six statistical blocks: shade trees (shade percentage and species abundancy), soil characteristics (fertility), foliar diseases, coffee plant characteristics (age and size), coffee growth and yield. We used partial least square path modelling (PLS-PM), i.e. a structural equation modelling approach used to understand and quantify interactions between the six blocks. Shade trees (mostly the associated shade percentage) had direct positive effects on foliar disease severity and incidence and soil quality, while having negative effects on coffee growth and yield. Soil characteristics (carbon, nitrogen, litter index, water infiltration potential) were negatively correlated with foliar diseases. An excessive shade percentage then had an indirect negative effect on coffee growth and yield due to the increased prevalence of foliar diseases. Finding the optimal shade cover can help reduce foliar diseases and enhance coffee berry production. The 'dose effect' of shade cover must also be considered because excessive shade, as well as lack of shade, have negative impacts on coffee growth and yield. Overall, effective shade management requires an analysis of trade-offs between soil quality, disease regulation and yield gains. In conclusion, PLS-PM turned out to be a good tool for studying agroecosystem networks and enabled us to put forward some foliar disease management and coffee yield enhancement guidelines

Ecosystem services evaluation as a tool for the design of cropping systems

UMR SYSTEM : équipe CONSYSTOver several decades, agricultural scientists and practitioners have developed frameworks to help farms in the design/management of their cropping systems. Approaches such as regional diagnoses, yield gap analysis, multicriteria assessment of agricultural systems, prototyping, participatory modeling, have been used to this aim, with varied outcomes and successes. Such approaches have included criteria related to the protection of the environment. The Ecosystem Services (ES) framework has emerged as a tool to conciliate the interests of human societies as a whole with the interests of individual or associate entrepreneurs. For this to occur, ES must be explicitly and systematically integrated into decision making by individuals, corporations, and governments (Daily et al., 2009). We are working on including this framework in cropping system design, so that land managers include the provision of diverse ecosystem services in their decision making about agricultural crops and practices. In this presentation, we show on specific case studies in temperate and tropical environments how the structure (strategic decision making) and management (tactical decision making) of complex agricultural systems can change the delivery of ES. We show that some cropping systems are particularly promising in delivering balanced sets of ecosystems services. Nevertheless, the introduction of biological diversity into cropping systems is a knowledge intensive strategy, and its outcomes are tightly linked to the context. Moreover, a particular strategy might be profitable one year, and produce negative outcomes the following year. We present an example of adaptative management of agricultural systems, where decision rules based on the environment or on the crop stand are used to customize practices to the current context, providing ES in a sustained way. We then propose different places in the cropping system design pathway where these ES framework and measurement can be usefully introduced, in order to conciliate the profitability and/or resilience of food production with the delivery of ES from these systems. We conclude on the way ahead to fully integrate the ES framework in cropping system design, so that this framework achieves part of its promises regarding the modification of decision making in agriculture and consequently the development of a greener agriculture

Modeling attainable yield and yield losses due to pests and diseases to compare performances of coffee farming systems

National audienc

Ecosystem services provided by coffee agroecosystems across a range of topo-climatic conditions and management strategies

National audienc

Shade trees have higher impact on soil nutrient availability and food web in organic than conventional coffee agroforestry

International audienceConventional, intensively managed coffee plantations are currently facing environmental challenges. The use of shade trees and the organic management of coffee crops are welcome alternatives, aiming to reduce synthetic inputs and restore soil biological balance. However, little is known about the impacts of the different types of shade tree species on soil functioning and fauna. In this paper, we assess soil nutrient availability and food web structure on a 17-year old experimental coffee plantation in Turrialba in Costa Rica. Three shade types (unshaded coffee, shaded with Terminalia amazonia, and shaded with Erythrina poepiggiana) combined with two management practices (organic and conventional) were evaluated. Total C and N, inorganic N and Olsen P content, soil pH, global soil fertility, and nematode and microarthropod communities were measured in the top 10 cm soil layer, with the objective of determining how shade tree species impact the soil food web and soil C, N and P cycling under different types of management. We noted a decrease in soil inorganic N content and nematode density under conventional management (respectively -47% and -91% compared to organic management), which suggested an important biological imbalance, possibly caused by the lack of organic amendment. Under conventional management, soil nutrient availability and fauna densities were higher under shade, regardless of the shade tree species. Under organic management, only soils under E. poeppigiana, a heavily pruned. N-2 -fixing species, had increased nutrient availability and fauna density, while T amazonia shade had a null or negative impact. The effects of coffee management and shade type on soil nutrient availability were mirrored by changes in soil food web structure. Higher fertility was recorded in soil with balanced food webs. These results emphasize the importance of the choice of shade tree species for soil functions in low input systems, more so than in fertilized system

Ecosystem services functional motif: a new concept to analyse and design agroforestry systems

National audienc