Recycling nutrients from horse manure: effects of bedding type and its compostability

Authors

• Riikka Keskinen Natural Resources Institute Finland (Luke)
• Markku Saastamoinen Natural Resources Institute Finland (Luke)
• Johanna Nikama Natural Resources Institute Finland (Luke)
• Susanna Särkijärvi Natural Resources Institute Finland (Luke)
• Marianna Myllymäki Natural Resources Institute Finland (Luke)
• Tapio Salo Natural Resources Institute Finland (Luke)
• Jaana Uusi-Kämppä Natural Resources Institute Finland (Luke)

DOI: https://doi.org/10.23986/afsci.60443

Keywords:

horse manure, bedding material, nutrient cycling, composting

Abstract

Manure constitutes a nutrient resource that should be efficiently recycled in agriculture. We assessed the nutrient cycling properties of three bedding materials (peat, wood shavings and pelleted straw) in horse manure by comparing their compostability, ability to retain nitrogen (N) and phosphorus (P) under rainfall and capacity to release N when mixed with soil. Manure with pelleted straw bedding had superior composting characteristics as it lost half of its dry mass, reached temperatures >60 °C and ended up having a carbon (C) to N (C:N) ratio of <15. In percolated water, 4–11% of total manure N and 5–23% of total manure P was leached during a 2 h 15 min event of artificial rainfall. Peat manure was most susceptible to P loss. In all fresh manures, C:N ratio exceeded 30, which led to net N immobilization in soil. Composting decreased the C:N leading to a slight positive or an insignificant fertilizer effect.