Towards low-cost soil fertility sensor systems for smallholder food security in Kenya

Agricultural production is increasingly threatened by environmental changes, including climate variability and soil degradation. These challenges have led to a pressing need for adaptive strategies to maintain soil health and optimize nutrient use. Smallholder farmers in low- and middle-income countries (LMICs) often lack the capacity for continuous soil monitoring due to the high costs associated with conventional soil testing. However, even in developed nations, access to affordable, sustainable soil health assessment tools remains limited. The current available sensor electrodes are traditionally made from non-biodegradable materials, contributing to electronic waste and environmental pollution. This project aims to develop low-cost, biodegradable soil nutrient sensors using easily accessible materials, including waste newspaper, carbon black (or charcoal), graphite, egg yolk, and gum arabic among other additives. The electrodes will be fabricated through block printing techniques, ensuring scalability and adaptability for low-tech, decentralized production. Enzyme modification will be conducted to enable ion selectivity therefore enabling real-time soil analysis through electrochemical detection of key nutrients such as nitrate, phosphate, and potassium. By integrating these eco-friendly materials and techniques, the proposed sensors will offer an affordable, sustainable, and effective solution for real-time soil nutrient monitoring. This will empower farmers with real-time, data-driven insights, supporting sustainable agricultural practices and climate resilience.