Socio-technical fertiliser interventions to enhance on-farm productivity

This thesis explored how smallholder farmers perceive and manage soil fertility, focusing on their use of mulch, manure, and mineral fertilisers, and how these practices are shaped by agronomic, socio-economic, and institutional factors. This thesis shows that farmers have real perceptions of soil fertility decline, especially in intensively cultivated areas with identified causes including continuous cropping without fallow and without the adequate use of mineral and organic fertilisers, bush burning, overgrazing, and soil compaction. The thesis shows that beyond farmers′ coping mechanisms, which is their improvisation and adaptation skills in the face of declining soil fertility, addressing low productivity and declining soil fertility requires context-specific, integrated soil fertility management approaches that align with farmers′ needs and opportunities, and local agroecological conditions. This is particularly important because not all farmers are equally placed to achieve enhanced productivity. Many farmers are lagging economically, not least because they lack resources to purchase mineral fertilisers, but also because they often lack resources even to successfully implement their coping strategies, for example procuring tractor services early enough to enable early planting.