Potential of biochar with crop residues in maize systems of Kenya: Ex-ante assessment for strategic guidance of research, investment and policy

Decisions on investment and policy require answers to key questions about the scalability, economic viability, and long-term effects of biochar use under realistic scenarios. Information on market size is key to drive advancements in delivery models, product formulation, regulatory frameworks, and fiscal incentives for effective and sustainable integration into the agri-food value chains. This ex-ante upscaled assessment aims to provide clarity on the potential scale and impact of biochar use in maize systems of Kenya by leveraging official data on land use, crop yields and fertilizer statistics, findings from research and case studies, all while accounting for varied need of residues, uncertainties and safety margins. A modelling procedure (Figure 1) with sequential operations starting from grain production data over standard conversion to residue quantities, deductions of competing pulls for livestock, resource recovery from pyrolytic processes, and dose-response yield gain was implemented that provides a comprehensive approach to evaluating agricultural efficiency and sustainability. As the benefit of soil health interventions is manifested over multiple years, these steps were looped, and legacy effects carried forth. Input data and conversion factors were furnished or reviewed by selected informants that are experts or practitioners in the field, ensuring robust and representative outcome. This framework and methods can be replicated across other geographic scales and regions. Besides the biophysical potential, the financial viability of biochar use was evaluated against prices of production, grain and fertilizer. The main factors used for conversion and response calculation are summarized in Annex #1. Results presented in this brief can help stakeholders anticipate the likely-hood outcomes and make informed decisions about the adoption and implementation.