Assessing the impact of long-term soil phosphorus on N-transformation pathways using 15N tracing

A laboratory incubation study was conducted on a temperate grassland soil to quantify the main mineral nitrogen (N) transformation rates and pathways via a15N tracing approach. Soil samples were taken from long-term phosphorus (P) trial investigate effects gross N-transformations under high low amendment. The soils incubated over 2-week period treated with ammonium-nitrate (NH4NO3) which applied both without glucose amendment labelled 15N either ammonium (NH4+) or nitrate (NO3?) moiety at 50% atom enrichment. results showed immobilisation greatly outweigh mineralisation that NO3? predominantly produced heterotrophic nitrification. Individual for production quantified including oxidation of NH4+, recalcitrant labile organic N. Oxidation N NO3?, newly considered pathway, accounted between 63 83% total across various treatments P levels. This process significantly higher in low-P rather than high-P (p < 0.05), highlighting effect microbial community.