Denitrification in subsoils and groundwater in Ireland

Abstract

Excessive reactive nitrogen (N) in groundwater is of huge concern to surface water quality and atmospheric nitrous oxide (N2O) emissions via denitrification. Understanding denitrification rates and factors controlling denitrification over space and time is crucial for quantifying the effects of human activity on the N cycle, and for managing and mitigating the severe environmental consequences associated with excessive reactive N. Despite the extensive research in the topsoil, denitrification in subsoils, below the rooting zone, is not well understood. Subsoil (only at Johnstown Castle, JC) and groundwater denitrification rates and ratios of N2O/N2O+N2 were investigated at four agricultural sites; (JC) Johnstown Castle, grassland, (SH) Solohead, grassland, (OP) Oak Park, arable land and (DG) Dairy Gold, grassland.