Composting and storage of organic household waste with different litter amendments. II: nitrogen turnover and losses

Composting of N-rich wastes can be associated with substantial gaseous N losses, which mean loss of an essential plant nutrient but may also lead to environmental pollution. We investigated nitrogen dynamics and losses in household waste mixtures with different litter additives during composting, maturation and storage. Standardized, organic household waste was composted mixed with six litter amendments; straw, leaves, hardwood, softwood, paper and sphagnum peat. Samples were analysed for total and inorganic N and pH. Both the addition and the type of litter amendment greatly influenced pH changes and formation of nitrate during composting. Net N losses after 590 days were 43–62% in mixtures with litter additions, being lowest in the peat and the straw mixtures and highest in the paper mixture, and 70% in the control without litter. A conclusion of the study was that there is no obvious way to efficiently decrease N losses during composting through addition of litter materials.