Carving paths of sustainable intensification for smallholder farming in sub-Saharan Africa

Push-pull technology (PPT) is a strategy for controlling agricultural pests, improving soil fertility, diversifying farm output, and reducing gender and age disparities. The benefits of PPT have been demonstrated in East Africa, but efforts to upscale its adoption can face many challenges. Agroecosystems comprise social-ecological networks, with interactions that transcend spatial and temporal scales. These interactions form feedback loops that drive system dynamics, often towards counter-intuitive responses to policy or environmental change. Predicting and managing the behavior of such complex systems typically requires advanced mathematical formulations and precise knowledge, which are often not available for smallholder farming in sub-Saharan Africa. Imprecise indigenous information is in many cases ignored, and predictive social-ecological modelling is limited. We suggest the combined use of causal loop diagrams (CLDs) and qualitative mathematical models (QMMs) for analyzing social-ecological networks involved in upscaling PPT adoption in East Africa. Use of these intuitive tools as boundary objects in participatory model development facilitates exploitation of imprecise knowledge, and increases stakeholder engagement in policy formulation. The distinct characteristics of CLDs and QMMs allow independent representation of the dynamics of PPT adoption by households, landscape-scale control of crop pests and regional economics, as well as cross-scale interactions among these sub-systems. Analysis of system-wide feedback loops can identify leverage points and reduce policy resistance for sustainable intensification pathways, based on upscaling PPT adoption in East Africa.