Composting provides many benefits including significant reductions in mass and increased nutrient concentrations.
Caring for a single horse may result in more than 10 tons of waste (manure plus bedding) material annually. Composting of this waste material is a handling technique for small equine operations and it provides many benefits including reduced haulage requirements, significant reductions in mass, and increased nutrient concentrations. The objectives of this study, carried out by Rutgers University in New Jersey, was to compare four of the most common bedding materials used by equine operations on the chemical and physical characteristics of composted equine stall waste.
Groups of three horses were bedded on one of four different bedding types, including wood shavings, pelletized wood materials, long straw, and pelletized straw, for 16 hour per day for 18 days. Stalls were cleaned by trained staff daily and all contents removed was weighed and stored separately by bedding material on a level covered concrete pad for the duration study. Compost piles were constructed using piles of each bedding and each pile was equipped with a temperature sensor and data logger. Water was added and piles were turned weekly throughout the 100 day compost process. Initial and final samples were taken, dried and analyzed for dry matter mass, organic matter, inorganic nitrogen and soluble nutrients.
No significant temperature differences were observed among the bedding materials. The composting process resulted in significant reductions in dry matter mass for each of the four bedding materials. The composting process resulted in significant reductions in organic matter and the carbon to nitrogen ratio for all four bedding materials. The composted long straw material had higher concentrations of nitrogen than the composted wood shavings.
This study demonstrated that incorporating a simple aerobic composting system may greatly reduce the overall volume of manure and yield a material that is beneficial for land application in pasture based systems. The straw based materials may be better suited for composting and subsequent land application; however, factors such as suitability of the bedding material for equine use, material cost, labor, and availability must be considered when selecting a bedding material.
Summarized by: Krishona Martinson, PhD, Univ. of Minn.