| Abstract: |
The global agricultural sector faces the challenge of ensuring food security while minimizing the environmental impact of conventional practices. Waste-derived fertilizers have gained attention for their potential to enhance nutrient circularity, yet regulatory, environmental, and agronomic barriers hinder widespread adoption. To address these challenges, a multidisciplinary international conference was held in Lincoln, NE, in September 2024. The event had a dual purpose: (1) to synthesize current technical knowledge and research priorities on circular fertilizers, and (2) to evaluate whether an innovative conference structure, integrating farmer panels, interactive sessions with digital tools, recorded talks for public access, and field visits, could foster cross-sector learning and long-term knowledge transfer. This structure captured diverse perspectives in real time and facilitated collaborations between groups that rarely interact, leading to the launch of new interdisciplinary projects. A key outcome was bridging the gap between lab-based research and real-world agricultural needs. Research often occurs in controlled settings where limited farmer engagement can obscure practical challenges. By enabling direct dialogue with farmers, the conference aligned scientific priorities with field-level realities. Recorded talks extended educational reach beyond the event, while in-person interactions built strong professional networks. Interactive tools, such as shared Google Sheets, encouraged participants to provide live feedback and identify research priorities collectively. This synthesis, aimed at researchers, policymakers, and educators, summarizes both technical insights (e.g., biosolids, struvite, digestate, biochar, and per- and polyfluoroalkyl substances) and lessons learned from using the conference as an educational platform. Post-conference surveys and expert panels identified key future priorities: establishing fertilizer-grade quality standards, standardizing contaminant risk assessments, expanding long-term field trials, and enhancing outreach frameworks. Overall, the findings underscore that circular fertilizers are scientifically viable but require coordinated regulatory, agronomic, and communication strategies to accelerate adoption. |