This project addresses the challenge of scaling climate smart nutrient management among African smallholder farmers by addressing the institutional factors and conditions relating to CSA knowledge service delivery (the CCAFS overall research question). It aims to understand and improve the ‘scaling readiness’ of climate smart, nutrient management decision support tools (DST) in different institutional environments: Ethiopia and Tanzania. ‘Scaling readiness’ is seen as the product of: (a) the fit between the DSTs (and its constituent climate smart nutrient management advices) and their envisaged users who operate at different scales, and; (b) the necessary (institutional) conditions which enable scaling by these different actors (i.e. extension, NGOs, agro-dealers). By working directly with different users operating at different scales, we examine the user logics that can inform the design of better decision support tools and the enabling (institutional) environments, which together shape the effective scaling of climate smart nutrient management advice.