Worked on enhancing the robustness of the FAN (Fast Agro-ecosystem Nitrogen) model within the E3SM-Project/E3SM repository, focusing on dynamic crop conditions and transient land use. Addressed numerical stability by implementing skip-logic for cells with very small weights, ensuring calculations only proceed where meaningful. Improved model consistency by allocating and initializing FAN-related variables regardless of the use_fan flag, supporting reliable behavior across different configurations. The work leveraged Fortran programming and numerical simulation techniques, applying biogeochemistry and climate modeling expertise to deliver a targeted feature that strengthens the model’s ability to handle complex, evolving agricultural scenarios without introducing instability.