Abstract for: Comparative Phosphorus Governance: Modeling Management Practices Across Different Soil Types

The core problem is the global challenge of phosphorus governance. While essential for agriculture, mismanagement leads to severe environmental issues like eutrophication. A key complication is that phosphorus dynamics and (consequently) effective management strategies differ significantly across different soil types, such as Mollisols and Oxisols. Current phosphorus management policies often fail to account for these soil-specific differences. This paper introduces a comparative SD modeling framework to test scenarios. This study employs a comparative system dynamics modeling approach to evaluate phosphorus management across contrasting soil types (Mollisols and Oxisols). We developed causal loop diagrams to conceptualize soil-specific phosphorus dynamics and then built a quantitative simulation model. This model explicitly incorporates key soil characteristics as parameters and allows for scenario-based analysis of various management practices and environmental conditions. Findings: Mollisols show runoff/eutrophication risks and climate sensitivity, while Oxisols face fertility limitations. Early modeling surprisingly suggests more manure can initially lower water phosphorus. Future Work: Plans include enhancing farmer decision-making in the model, refining phosphorus dynamics (fixation, mobility, saturation), incorporating soil organic matter and climate impacts, and extending analysis for long-term sustainability across soil types. This research underscores the necessity of soil-specific phosphorus governance, contrasting with generalized approaches. Practitioners can recognize the distinct management challenges in Mollisols (runoff) versus Oxisols (fertility). Researchers gain a novel comparative system dynamics framework integrating soil science and policy. This methodology can be applied to broader nutrient management and informs tailored strategies for diverse soil contexts globally, advancing sustainable agriculture.