Business Models for Horse Manure Utilisation in the European Union: Compost-Based Products, Market Pathways, and Carbon Integration

Horse husbandry in Europe has shifted from agricultural production toward leisure, sport, and therapeutic uses in peri-urban areas. Consequently, horse manure has increasingly become a logistical, regulatory, and economic challenge. Controlled composting has long been recognised as a treatment option for horse manure, offering hygienisation, organic matter stabilisation, and improved nutrient predictability. However, despite its technical feasibility, composting remains underutilised in decentralised and small-to-medium horse-keeping systems. This study investigated the potential of compost-based value chains for horse manure within the EU. It combined a comparative literature analysis of horse manure composting with a systematic mapping of compost products, applications, and business models implemented across EU member states. Feedstock-specific properties of horse manure, including bedding-driven carbon-to-nitrogen ratios, emission dynamics, and hygienisation requirements, were linked to market pathways, regulatory frameworks, and organisational archetypes. Results showed that composting transforms horse manure from a disposal burden into a flexible platform for differentiated products, primarily positioned as soil improvers rather than high-effect nitrogen fertilisers. Effective value creation depends on application-driven compost formulation, process control to ensure hygienic and agronomic quality, and organisational models that match spatial context, scale, and regulatory conditions. Centralised, municipal, and decentralised business models each present distinct advantages and constraints, while product differentiation through compost-biochar blends or growing media components offers emerging opportunities. Overall, the study demonstrated that integrating compost science with business model design is essential for unlocking the economic and environmental potential of horse manure in European peri-urban systems. Graphical abstract