Navigating farming-BMP-policy interplay through a dynamical model

Abstract

Growing nutrient fertilization has imperiled freshwater resources throughout the world. There is a conflict of interest between farmers and local environmental organizations who are concerning about nutrient pollution in waterbodies. Adoption of best management practices (BMPs) by agricultural producers, while having potential to improve the situation, is not always easy to achieve. Here we developed a dynamical system model to capture the interaction among farmers responding to BMPs. Specifically, we based our model on replicator dynamics and defined fine and compensation for BMP adoption as functions of the amount of applied nitrogen. The farmers could also adopt two alternative strategies: business as usual and leaving the system. The model allowed us to investigate how incentive and restrictive regulations affect the behavior of farmers and the stability of the coupled system. Importantly, the model resulted in conditions that led to different system-level outcomes (e.g., sustained, collapse, mixed strategy between adopting BMPs and business-as-usual) as clear functions of biophysical, economic, and policy parameters. The results suggested that under certain circumstances, incentive programs can be ineffective or inappropriate, and such policies can lead to out-migration. These results offer guidelines on how to design restrictive and incentive policies or their combinations to achieve certain goals.