Cross‐system comparisons of soil nitrogen transformations and nitrous oxide flux in tropical forest ecosystems

Abstract

Soil nitrogen transformations and nitrous oxide flux across the soil‐air interface were measured in a range of tropical forest sites in Costa Rica, Brazil, and Hawaii. Nitrogen mineralization and nitrification potentials were high in the relatively fertile Costa Rica sites and the Amazonian oxisol/ultisols (>1.5 μg g−1 d−1 of N mineralized), intermediate in Amazonian white sand soils (0.5‐0.8 μg g−1 d−1) and low in the Hawaiian montane sites (<0.5 μg g−1 d−1). Nitrous oxide fluxes ranged from 0 to 6.2 ng cm−2 h−1 of N; mean flux per site was highly correlated with mean nitrogen mineralization across 26 sites. These correlated patterns of nitrogen cycling and trace gas production could be useful in the development of regional‐ and global‐scale estimates of nitrous oxide fluxes from tropical forests.