Utilising diagnostic features to define the safe operating space for nutrient management in smallholder farming systems

Smallholder farming systems dominate Ethiopia’s agricultural landscape and play a central role in national food security. However, these systems are commonly characterized by limited access to soil testing services, minimal external inputs, and a reliance on blanket fertiliser recommendations that fail to account for the substantial diversity of soils and agro-ecological conditions. This study explores a practical alternative for guiding nutrient use by utilising diagnostic soil features. These features reflect soil forming processes and indicate how effectively soils can store and supply nutrients. By linking diagnostic soil features to nutrient availability, crop response and fertiliser use efficiency, the study defines a safe operating space for fertiliser management. This safe operating space is conceptualised as the range of nutrient inputs within which crop productivity can be enhanced while minimising the risks of nutrient losses and environmental pollution. Overall, the approach demonstrates the potential of diagnostic soil features as a low-cost, practical framework for nutrient management in smallholder farming systems.