Ammonia emissions during the initial phase of microbial degradation of solid and liquid cattle manure

The maximum speci®c ammonia emissions from liquid manure (LM) and solid manure containing 2.5 kg straw/livestock unit (LU)/day (SM 2.5) or 15 kg straw/LU/day (SM 15) increased in the sequence LM < SM 2.5 < SM 15 (662.6 < 3163.7 < 6299.8 lg NH3±N/h/kg). These emission levels were attained soon after the maximum temperatures (22.9°C < 34.3°C < 69.5°C) induced by microbial self-heating had been reached. After that, NH‡ 4 was microbially re-bound in amounts that increased with a higher C content and a widening C:N ratio, i.e. also in the sequence LM < SM 2.5 < SM 15. Over a period of 15 to 16 days, 6.0% (LM), 10.8% (SM 2.5) and 5.9% (SM 15) of the Ntotal was emitted. When the accumulated ammonia emissions were extrapolated beyond this period of investigation, it was concluded that, over longer storage periods, solid manure o€ers better biological conditions for low ammonia emissions than liquid manure