Agriculture remains the backbone of most African economies, yet land degradation severely hampers agricultural productivity. Over the last decades, scientists and development practitioners have advocated integrated soil fertility management practices to improve soil fertility. However, their adoption rates are low, partly because many farmers in sub-Saharan Africa are not fully aware of the principles of this system innovation. This has been attributed to a wide communication gap between farmers and other agricultural actors in agricultural knowledge and innovation systems. We add (...) to the literature by applying innovation system approaches to ISFM awareness processes. This study aims to assess if AKIS are effectively disseminating ISFM knowledge by comparing results from two sites in Kenya and Ghana, which differ in the uptake of ISFM. Social network measures and statistical methods were employed using data from key formal actors and farmers. Our results suggest that the presence of weak knowledge ties is important for the awareness of ISFM at both research sites. However, in Kenya AKIS are more effective as there is a network of knowledge ties crucial for not only dissemination but also learning of complex innovations. This is largely lacking in Ghana where integration of formal and informal agricultural knowledge systems may be enhanced by fostering the function of informal and formal innovation brokers. (shrink)