Nitrogen turnover in alternatives to peat

Abstract

Samples of a sphagnum peat and 14 different alternatives were incubated aerobically at pH 6.0 to 6.5 for 12 weeks at 15 °C to study the transformations of added ammonium ions and losses by volatilisation. Turnover of N was generally greater in coir-based materials and in composted animal and domestic wastes than in most bark and paper products. There was little evidence of significant gaseous losses of NH₃; changes in ammonium concentration resulted largely from nitrification, but simultaneous immobilisation of ammonium and nitrate (and sometimes denitrification) restricted the accumulation of the latter. The decline in ammonium content was generally in direct proportion to the initial amount of ammonium present and was not clearly related to the organic N content or the C:N ratio of the material.