Intensification of US livestock production, generating an estimated 1.27 billion metric tons of manure per year from nearly 10 billion animals, presents both a nutrient resource and an environmental challenge. This technical review synthesizes current knowledge on manure's agronomic and soil health benefits versus its environmental risks. The study compares different management approaches, land application, stockpiling, lagoons, and critically assesses advanced treatment and valorization technologies, including anaerobic digestion, solid-liquid separation, nutrient recovery (struvite precipitation, ammonia stripping), biochar co-composting, and precision application tools (injection, variable-rate spreading, and real-time nutrient sensors). Adoption drivers such as regulatory frameworks (Clean Water Act, concentrated animal feeding operation permits, and California SB 1383), economic incentives (Environmental Quality Incentives Program [EQIP] cost-share and carbon and nutrient credit markets), and digital innovations are also evaluated alongside persistent barriers of high capital costs, logistical constraints in nutrient transport, knowledge gaps in emission quantification (CH4, N2O, and NH3), pathogen fate, and site-specific trade-offs among air, water, and soil quality. The review also outlines potential future scenarios, from incremental technology mainstreaming to integrated circular biorefineries, and highlights research priorities to optimize manure as a circular resource while safeguarding ecosystem and human health. By contextualizing manure management within a climate-resilient, circular agricultural economy, this review identifies the research gaps and informs researchers, extension agents, and policymakers on strategies to advance sustainable livestock systems in the United States and beyond.
US livestock and poultry produce ∼1.27–1.45 billion metric tons of manure each year. When managed well, manure adds organic carbon and nutrients, building soil organic matter, aggregation, and water‐holding capacity, and reducing synthetic fertilizer needs (shown in long‐term trials). When mismanaged, it drives water pollution because manure N:P ratios often overapply phosphorus, creating “legacy P” that fuels eutrophication for decades. Manure can also carry pathogens, antibiotic resistance genes, heavy metals, per‐ and polyfluoroalkyl substances, and microplastics, and it emits NH3, CH4, and N2O, sometimes causing “pollution swapping” between air, water, and climate. The review evaluates solutions (digesters, covers, separation, composting, nutrient recovery, precision sensing) and concludes that scaling requires better data/measurement, reporting, and verification (MRV), incentives, and coordinated policy.
© 2026 The Author(s). Journal of Environmental Quality © 2026 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.