Manureshed management to overcome longstanding nutrient imbalances in US agriculture

The uncoupling of animal and crop production has resulted in long-term accumulation of manure nutrients in many areas, contributing to nutrient pollution. Prudent recycling of manure's nutrient resources requires reconnecting operations that produce manure with agricultural lands in need of nutrients. Thus the need to frame manure management via "manuresheds": the land (i.e. cropland, rangeland) surrounding livestock production operations where nutrients can be recycled on agricultural lands while balancing goals for production, envi-ronmental quality, and quality of life. We explore manureshed management as an evolution of national, regional, and local trends in nutrient sources and sinks. Results of our temporal assessments highlight not only system inertia, but the dynamic nature of nutrient flows and the potential for manureshed management to reverse nutrient imbalances at various scales. As a tool for a circular economy, manureshed management requires co-ordination beyond the farmgate, engaging specialists, industries, and other stakeholders.