Composting caged-layer manure and dairy feedlot manure in passively aerated and turned windrows

摘要

The object of this study was to compare composting of animal manure in passively aerated (PAWs) and turned (TWs) windrows in terms of changes in compost biomass temperature and physical and chemical characteristics. A mixture of poultry (laying hen)manure (PM) and tall fescue grass clippings was composted in 1998. Dairy cattle feedlot manure (DM), with a small amount of wood shavings, was composted in 1999-2000. The PAWs and TWs generally exhibited similar patterns of change with time with a smalldifference in absolute values of temperature, moisture, ammonia-N, pH, electrical conductivity, ash, carbon,, total-N, C/N ratio and S concentration. However, the actual values for these properties were considerably different in the PM and DM compostingsystems. Temperature of 55°C or more was maintained for two weeks or longer in both manure composts. The DM compost had higher moisture, pH, carbon, and C/N ratio, but lower ash, total N and S than the PM compost. Volume reduction was greater in TWs than in the PAWs, and the finished compost had a finer texture in the former than in the latter. The PAWs retained more C than the TWs for both PM and DM but more N was retained only in the PAWs for PM. Results suggest that the less labor and capital-intensive passive aeration windrow system performance was not much different from that of the turned windrow system.