The effect of carbon availability on N2O emissions is moderated by soil phosphorus.

This research investigated the effect of long-term phosphorus (P) addition relative to carbon (C) availability on nitrous oxide (N 2 O) emissions from an ungrazed grassland soil via two incubation experiments. No significant effect of soil P on N 2 O was found under C-limited conditions, while under added-C, cumulative N 2 O was significantly higher from low-P (p < 0.05) rather than high-P soils. CO 2 was not significantly different between P-levels. This highlights the influence of soil P on N 2 O emissions under non C-limiting conditions. This is one of the first studies demonstrating available-C moderating the effect of P on N 2 O emissions from temperate grassland soils. • Phosphorus effects on N 2 O emissions from soils are poorly understood. • Carbon limitation masks effects of phosphorus on nitrous oxide emissions. • When soil not C-limited, N 2 O reduced at higher P concentrations. • Manipulation of C:N:P ratio can reduce N 2 O emissions from grassland. [ABSTRACT FROM AUTHOR]